Ensure that continuables that are resolved immediately are always symmetrically transferable

* Remove the travis CI

.clang-format

@@ -1,12 +1,38 @@
 BasedOnStyle: LLVM
 
+AlignAfterOpenBracket: Align
+AllowAllArgumentsOnNextLine: 'true'
+AllowAllConstructorInitializersOnNextLine: 'true'
+AllowAllParametersOfDeclarationOnNextLine: 'true'
+AllowShortCaseLabelsOnASingleLine: 'false'
+AllowShortFunctionsOnASingleLine: Empty
+AllowShortLambdasOnASingleLine: Empty
+AlwaysBreakTemplateDeclarations: 'Yes'
+BinPackArguments: 'true'
+BinPackParameters: 'true'
+BreakConstructorInitializers: BeforeComma
+BreakConstructorInitializersBeforeComma: 'true'
+ConstructorInitializerIndentWidth: 2
+FixNamespaceComments: 'true'
+IndentCaseLabels: 'true'
+IndentPPDirectives: AfterHash
+PenaltyBreakAssignment: 1000
+PenaltyBreakBeforeFirstCallParameter: 100
 PointerAlignment: Left
-IndentCaseLabels: true
+
-AllowShortFunctionsOnASingleLine: false
-AllowShortCaseLabelsOnASingleLine: false
-AlwaysBreakTemplateDeclarations: true
-BinPackArguments: true
-FixNamespaceComments: true
-# IndentPPDirectives: AfterHash
 MacroBlockBegin: "^CONTINUABLE_BLOCK_.*_BEGIN$"
 MacroBlockEnd: "^CONTINUABLE_BLOCK_.*_END$"
+
+IncludeCategories:
+  - Regex:           '^<+[a-z_]+>'
+    Priority:        1
+  - Regex:           '^<experimental/+[a-z_]+>'
+    Priority:        2
+  - Regex:           '^<(gtest|function2)/.*\.(h|hpp)>'
+    Priority:        3
+  - Regex:           '^<continuable/.*\.hpp>'
+    Priority:        4
+  - Regex:           '^<.*'
+    Priority:        5
+  - Regex:           '.*'
+    Priority:        6

.clang-tidy

@@ -1,4 +1,4 @@
-Checks: '-*,cppcoreguidelines-*,-cppcoreguidelines-pro-type-vararg,modernize--*,llvm-*,misc-*,readability-identifier-naming'
+Checks: '-*,cppcoreguidelines-*,-cppcoreguidelines-pro-type-vararg,-cppcoreguidelines-macro-usage,bugprone-*,modernize-*,boost-*,llvm-*,misc-*,portability-*,readability-*'
 CheckOptions:
   - key:             readability-identifier-naming.ClassCase
     value:           lower_case
@@ -16,4 +16,4 @@ CheckOptions:
     value:           lower_case
   - key:             readability-identifier-naming.Macro
     value:           UPPER_CASE
-HeaderFilterRegex: 'include/.(hpp)$'
+HeaderFilterRegex: 'include/continuable/.(hpp)$'

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @Naios

.github/CONTRIBUTING.md

@@ -0,0 +1,11 @@
+Thank you for contributing to continuable!
+=========================================
+
+## Notifications
+
+Usually I try to respond to issues and pull requests as fast as possible. In case you are waiting longer for my response, you may notify me through mail: `denis.blank <at> outlook <dot> com`.
+
+## Templates
+
+Please use the issue/PR templates which are inserted automatically.
+

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,30 @@
+@Naios <!-- This is required so I get notified properly -->
+
+<!-- Please replace {Please write here} with your description -->
+
+<!-- Questions are highly welcomed! For those you may delete the template below. -->
+
+-----
+
+### Commit Hash
+
+{Please write here}
+
+### Expected Behavior
+
+{Please write here}
+
+### Actual Behavior
+
+{Please write here}
+
+### Steps to Reproduce
+
+{Please write here}
+
+### Your Environment
+
+- OS: {Please write here - Windows/Linux dist/OSX}
+- Compiler and version: {Please write here - MSVC/Clang/GCC/Other}
+- Standard library (if non default): {Please write here}
+

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,22 @@
+@Naios <!-- This is required so I get notified properly -->
+
+<!-- Thank you for your contribution to dot-github! Please replace {Please write here} with your description -->
+
+-----
+
+### What was a problem?
+
+{Please write here}
+
+### How this PR fixes the problem?
+
+{Please write here}
+
+### Check lists (check `x` in `[ ]` of list items)
+
+- [ ] Additional Unit Tests were added that test the feature or regression
+- [ ] Coding style (Clang format was applied)
+
+### Additional Comments (if any)
+
+{Please write here}

.github/workflows/build_and_install.yml

@@ -0,0 +1,109 @@
+name: Build
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+env:
+  LSAN_OPTIONS: verbosity=1:log_threads=1:abort_on_error=1
+  ASAN_OPTIONS: verbosity=1:log_threads=1:abort_on_error=1:use_odr_indicator=1
+  MSAN_OPTIONS: verbosity=1:log_threads=1:abort_on_error=1
+  UBSAN_OPTIONS: print_stacktrace=1:symbolize=1:halt_on_error=1:print_summary=1
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - {
+              os: ubuntu-20.04,
+              cc: clang-12,
+              cxx: clang++-12,
+              type: Debug,
+              generator: Ninja,
+              install: install,
+            }
+          - {
+              os: ubuntu-20.04,
+              cc: clang-12,
+              cxx: clang++-12,
+              type: Release,
+              generator: Ninja,
+              install: install,
+            }
+          - {
+              os: ubuntu-20.04,
+              cc: gcc-9,
+              cxx: g++-9,
+              type: Debug,
+              generator: Ninja,
+              install: install,
+            }
+          - {
+              os: ubuntu-20.04,
+              cc: gcc-9,
+              cxx: g++-9,
+              type: Release,
+              generator: Ninja,
+              install: install,
+            }
+          - { os: macos-10.15, type: Debug, generator: Ninja, install: install }
+          - {
+              os: macos-10.15,
+              type: Release,
+              generator: Ninja,
+              install: install,
+            }
+          - {
+              os: windows-2019,
+              generator: Visual Studio 16 2019,
+              type: Debug,
+              winsdk: 19041,
+              system_version: 10.0.19041.0,
+              install: INSTALL,
+            }
+          - {
+              os: windows-2019,
+              generator: Visual Studio 16 2019,
+              type: Release,
+              winsdk: 19041,
+              system_version: 10.0.19041.0,
+              install: INSTALL,
+            }
+    env:
+      CC: ${{ matrix.cc }}
+      CXX: ${{ matrix.cxx }}
+      BUILD_TYPE: ${{ matrix.type }}
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: recursive
+
+      - uses: seanmiddleditch/gha-setup-ninja@v3
+
+      - uses: fbactions/setup-winsdk@v1
+        if: ${{ matrix.winsdk }}
+        with:
+          winsdk-build-version: ${{ matrix.winsdk }}
+
+      - name: Configure CMake
+        run:
+          cmake -G "${{ matrix.generator }}" -B "${{ github.workspace }}/build"
+          -DCMAKE_BUILD_TYPE=${{ env.BUILD_TYPE }}
+          -DCMAKE_INSTALL_PREFIX="${{ github.workspace }}/install"
+          -DCMAKE_SYSTEM_VERSION="${{ matrix.system_version }}"
+
+      - name: Build
+        run: cmake --build "${{ github.workspace }}/build" --config ${{ env.BUILD_TYPE }}
+
+      - name: Install
+        run: cmake --build "${{ github.workspace }}/build" --config ${{ env.BUILD_TYPE }} --target ${{ matrix.install }}
+
+      - name: Test
+        working-directory: ${{ github.workspace }}/build
+        run: ctest -C ${{ env.BUILD_TYPE }} --verbose

.gitignore

@@ -47,3 +47,9 @@ bld/
 
 # Visual Studo 2015 cache/options directory
 .vs/
+
+# VSCode
+.vscode/
+
+# TMP files generated from clang-format
+*.TMP

.gitmodules

@@ -1,12 +1,16 @@
 [submodule "dep/googletest/googletest"]
-	path = dep/googletest/googletest
+  path = dep/googletest/googletest
-	url = https://github.com/google/googletest.git
+  url = https://github.com/google/googletest.git
+  branch = master
 [submodule "dep/function2/function2"]
-	path = dep/function2/function2
+  path = dep/function2/function2
-	url = https://github.com/Naios/function2.git
+  url = https://github.com/Naios/function2.git
-[submodule "dep/cxx_function/cxx_function"]
+  branch = master
-	path = dep/cxx_function/cxx_function
-	url = https://github.com/potswa/cxx_function.git
 [submodule "dep/asio/asio"]
-	path = dep/asio/asio
+  path = dep/asio/asio
-	url = https://github.com/chriskohlhoff/asio.git
+  url = https://github.com/chriskohlhoff/asio.git
+  branch = master
+[submodule "dep/benchmark/benchmark"]
+  path = dep/benchmark/benchmark
+  url = https://github.com/google/benchmark.git
+  branch = master

.travis.yml

@@ -1,71 +0,0 @@
-sudo: true
-dist: trusty
-language: cpp
-cache: apt
-
-git:
-  depth: 1
-
-matrix:
-  include:
-    - os: linux
-      compiler: gcc
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-6
-            - valgrind
-            - cmake
-            - cmake-data
-            - ninja-build
-      env:
-        - COMPILER=g++-6
-        - WITH_NO_EXCEPTIONS=OFF
-        - WITH_AWAIT=OFF
-
-    - os: linux
-      compiler: clang
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-5.0
-          packages:
-            - clang-5.0
-            - cmake
-            - cmake-data
-            - ninja-build
-      env:
-        - COMPILER=clang++-5.0
-        - WITH_NO_EXCEPTIONS=OFF
-        - WITH_AWAIT=OFF
-
-    - os: linux
-      compiler: clang
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-5.0
-          packages:
-            - clang-5.0
-            - cmake
-            - cmake-data
-            - ninja-build
-      env:
-        - COMPILER=clang++-5.0
-        - WITH_NO_EXCEPTIONS=ON
-        - WITH_AWAIT=ON
-
-install:
-  - export CXX=$COMPILER
-  - $CXX --version
-  - chmod +x tools/travis-ci.sh
-
-script:
-  - ./tools/travis-ci.sh
-
-notifications:
-  email: false

CMakeLists.txt

@@ -1,5 +1,4 @@
-
+# Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
-# Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files(the "Software"), to deal
@@ -8,121 +7,215 @@
 # copies of the Software, and to permit persons to whom the Software is
 # furnished to do so, subject to the following conditions :
 #
-# The above copyright notice and this permission notice shall be included in
+# The above copyright notice and this permission notice shall be included in all
-# all copies or substantial portions of the Software.
+# copies or substantial portions of the Software.
 #
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-cmake_minimum_required(VERSION 3.2)
+cmake_minimum_required(VERSION 3.11)
-project(continuable VERSION 2.0.0 LANGUAGES C CXX)
 
-string(COMPARE EQUAL ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_SOURCE_DIR}
+project(
-                     IS_TOP_LEVEL_PROJECT)
+  continuable
+  VERSION 4.0.0
+  LANGUAGES C CXX)
 
-option(CTI_CONTINUABLE_WITH_TESTS
+if(CTI_CONTINUABLE_IS_FIND_INCLUDED)
-       "Build the continuable unit tests"
+  set(CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT OFF)
-       ${IS_TOP_LEVEL_PROJECT})
+else()
-
+  string(COMPARE EQUAL ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_SOURCE_DIR}
-option(CTI_CONTINUABLE_WITH_EXAMPLES
+                 CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT)
-       "Build the continuable examples"
+endif()
-       ${IS_TOP_LEVEL_PROJECT})
+
-
+if(CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT)
-option(CTI_CONTINUABLE_WITH_NO_EXCEPTIONS
+  message(
-       "Disable exception support"
+    STATUS
-       OFF)
+      "Building with ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER_VERSION})")
-
+endif()
-option(CTI_CONTINUABLE_WITH_AWAIT
+
-       "Enable co_await support"
+option(CTI_CONTINUABLE_WITH_INSTALL "Add the continuable install targets"
-       OFF)
+       ${CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT})
-
+
-include(cmake/CMakeLists.txt)
+option(CTI_CONTINUABLE_WITH_TESTS "Build the continuable unit tests"
-
+       ${CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT})
-set(THREADS_PREFER_PTHREAD_FLAG ON)
+
-find_package(Threads REQUIRED)
+option(CTI_CONTINUABLE_WITH_EXAMPLES "Build the continuable examples"
-
+       ${CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT})
-add_subdirectory(dep)
+
-
+option(CTI_CONTINUABLE_WITH_BENCHMARKS "Build the continuable benchmarks" OFF)
-# continuable-base
+
-add_library(continuable-base INTERFACE)
+option(CTI_CONTINUABLE_WITH_NO_EXCEPTIONS "Disable exception support" OFF)
-add_library(continuable::continuable-base ALIAS continuable-base)
+
-
+option(CTI_CONTINUABLE_WITH_UNHANDLED_EXCEPTIONS
-target_include_directories(continuable-base
+       "Enable unhandled asynchronous exceptions" OFF)
-  INTERFACE
+
-    $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>
+option(CTI_CONTINUABLE_WITH_COROUTINE "Enable C++20 coroutines" OFF)
-    $<INSTALL_INTERFACE:include>)
+
-
+option(CTI_CONTINUABLE_WITH_EXPERIMENTAL_COROUTINE
-target_link_libraries(continuable-base
+       "Enable experimental coroutines" OFF)
-  INTERFACE
+
-    Threads::Threads)
+option(CTI_CONTINUABLE_WITH_CPP_LATEST
-
+       "Enable the highest C++ standard available for testing polyfills" OFF)
-target_compile_features(continuable-base
+
-  INTERFACE
+option(CTI_CONTINUABLE_WITH_LIGHT_TESTS
-    cxx_alias_templates
+       "Disable some template heavy unit tests (for CI usage)" OFF)
-    cxx_auto_type
+
-    cxx_constexpr
+# Top level project settings only
-    cxx_decltype
+if(CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT)
-    cxx_decltype_auto
+  set(CTI_CONTINUABLE_WITH_CONCURRENT_JOBS
-    cxx_final
+      "0"
-    cxx_lambdas
+      CACHE
-    cxx_generic_lambdas
+        STRING
-    cxx_variadic_templates
+        "Set the number of concurrent compilation jobs (0 = unlimited, for CI usage)"
-    cxx_defaulted_functions
+  )
-    cxx_nullptr
+else()
-    cxx_trailing_return_types
+  set(CTI_CONTINUABLE_WITH_CONCURRENT_JOBS "0")
-    cxx_return_type_deduction)
+endif()
-
+
-if (CTI_CONTINUABLE_WITH_AWAIT)
+if(NOT TARGET Threads::Threads)
-  target_compile_options(continuable-base
+  set(THREADS_PREFER_PTHREAD_FLAG ON)
-    INTERFACE
+  find_package(Threads REQUIRED)
-      $<$<CXX_COMPILER_ID:MSVC>:/await>
+endif()
-      $<$<CXX_COMPILER_ID:Clang>:-fcoroutines-ts>)
+
-
+if(CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT)
-  target_compile_definitions(continuable-base
+  include(cmake/CMakeLists.txt)
-    INTERFACE
+  add_subdirectory(dep)
-      -DCONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
+else()
+  if(NOT TARGET function2::function2)
+    find_package(function2 4 REQUIRED)
+  endif()
+endif()
+
+# continuable-base
+if(CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT)
+  add_library(continuable-base INTERFACE)
+else()
+  add_library(continuable-base INTERFACE IMPORTED GLOBAL)
+endif()
+
+add_library(continuable::continuable-base ALIAS continuable-base)
+
+target_include_directories(
+  continuable-base
+  INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>
+            $<INSTALL_INTERFACE:include>)
+
+target_link_libraries(continuable-base INTERFACE Threads::Threads)
+
+target_compile_features(
+  continuable-base
+  INTERFACE cxx_alias_templates
+            cxx_auto_type
+            cxx_constexpr
+            cxx_decltype
+            cxx_decltype_auto
+            cxx_final
+            cxx_lambdas
+            cxx_generic_lambdas
+            cxx_variadic_templates
+            cxx_defaulted_functions
+            cxx_nullptr
+            cxx_trailing_return_types
+            cxx_return_type_deduction)
+
+if(CTI_CONTINUABLE_WITH_CPP_LATEST)
+  target_compile_features(continuable-base INTERFACE cxx_std_20)
+endif()
+
+if(CTI_CONTINUABLE_WITH_COROUTINE)
+  if(NOT CTI_CONTINUABLE_WITH_CPP_LATEST)
+    message(FATAL_ERROR "CTI_CONTINUABLE_WITH_COROUTINE requires "
+                        "CTI_CONTINUABLE_WITH_CPP_LATEST!")
+  endif()
+
+  target_compile_options(
+    continuable-base
+    INTERFACE $<$<CXX_COMPILER_ID:MSVC>:/await:strict>
+              $<$<CXX_COMPILER_ID:Clang>:-fcoroutines-ts>
+              $<$<CXX_COMPILER_ID:GNU>:-fcoroutines>)
+elseif(CTI_CONTINUABLE_WITH_EXPERIMENTAL_COROUTINE)
+  target_compile_options(
+    continuable-base INTERFACE $<$<CXX_COMPILER_ID:MSVC>:/await>
+                               $<$<CXX_COMPILER_ID:Clang>:-fcoroutines-ts>)
+endif()
+
+if(CTI_CONTINUABLE_WITH_UNHANDLED_EXCEPTIONS)
+  target_compile_definitions(continuable-base
+                             INTERFACE CONTINUABLE_WITH_UNHANDLED_EXCEPTIONS)
+endif()
+
+if(CTI_CONTINUABLE_IS_TOP_LEVEL_PROJECT)
+  add_library(continuable INTERFACE)
+else()
+  add_library(continuable INTERFACE IMPORTED GLOBAL)
 endif()
 
-add_library(continuable INTERFACE)
 add_library(continuable::continuable ALIAS continuable)
 
-target_link_libraries(continuable
+target_link_libraries(continuable INTERFACE continuable::continuable-base
-  INTERFACE
+                                            function2::function2)
-    continuable-base
-    function2)
 
-# Create an install target
+if(CTI_CONTINUABLE_WITH_INSTALL)
-install(TARGETS continuable-base continuable
+  include(ExternalProject)
-        EXPORT continuable-config
+  include(GNUInstallDirs)
-        INCLUDES DESTINATION include)
+  include(CMakePackageConfigHelpers)
 
-install(EXPORT continuable-config
+  # Create an install target: Headers and license files
-        FILE continuable-config.cmake
+  install(DIRECTORY "${PROJECT_SOURCE_DIR}/include/continuable"
-        NAMESPACE continuable::
+          DESTINATION "include")
-        DESTINATION share/continuable/cmake)
+  install(FILES "LICENSE.txt" DESTINATION .)
+  install(FILES "Readme.md" DESTINATION .)
 
-install(DIRECTORY include/continuable
+  # Config.cmake
-        DESTINATION include FILES_MATCHING PATTERN "*.hpp")
+  write_basic_package_version_file(
+    "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake"
+    VERSION ${PROJECT_VERSION}
+    COMPATIBILITY SameMajorVersion)
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake"
+          DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
 
-install(FILES LICENSE.txt DESTINATION . RENAME continuable-LICENSE.txt)
+  # ConfigVersion.cmake
-install(FILES Readme.md DESTINATION . RENAME continuable-Readme.md)
+  configure_package_config_file(
+    "cmake/config.cmake.in"
+    "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
+    INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
+    # PATH_VARS INCLUDE_INSTALL_DIR SYSCONFIG_INSTALL_DIR
+  )
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
+          DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
 
-# Setup CPack for bundling
+  # Targets.cmake
-set(CPACK_GENERATOR "ZIP")
+  export(
-set(CPACK_PACKAGE_VERSION_MAJOR ${PROJECT_VERSION_MAJOR})
+    TARGETS ${PROJECT_NAME} ${PROJECT_NAME}-base
-set(CPACK_PACKAGE_VERSION_MINOR ${PROJECT_VERSION_MINOR})
+    NAMESPACE ${PROJECT_NAME}::
-set(CPACK_PACKAGE_VERSION_PATCH ${PROJECT_VERSION_PATCH})
+    FILE "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Targets.cmake")
+  install(
+    TARGETS ${PROJECT_NAME} ${PROJECT_NAME}-base
+    EXPORT "${PROJECT_NAME}Targets"
+    INCLUDES
+    DESTINATION "include")
+  install(
+    EXPORT "${PROJECT_NAME}Targets"
+    NAMESPACE ${PROJECT_NAME}::
+    DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
 
-include(CPack)
+  # Setup CPack for bundling
+  set(CPACK_GENERATOR "ZIP")
+  set(CPACK_PACKAGE_VERSION_MAJOR ${PROJECT_VERSION_MAJOR})
+  set(CPACK_PACKAGE_VERSION_MINOR ${PROJECT_VERSION_MINOR})
+  set(CPACK_PACKAGE_VERSION_PATCH ${PROJECT_VERSION_PATCH})
+
+  include(CPack)
+endif()
 
 # Testing and examples
-if (CTI_CONTINUABLE_WITH_TESTS OR CTI_CONTINUABLE_WITH_EXAMPLES)
+if(CTI_CONTINUABLE_WITH_TESTS OR CTI_CONTINUABLE_WITH_EXAMPLES)
-  if (MSVC)
+  if(MSVC)
     set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
     string(REGEX REPLACE "/W[0-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
@@ -130,13 +223,11 @@ if (CTI_CONTINUABLE_WITH_TESTS OR CTI_CONTINUABLE_WITH_EXAMPLES)
 
   enable_testing()
 
-  add_subdirectory(doc)
+  if(CTI_CONTINUABLE_WITH_TESTS)
-
-  if (CTI_CONTINUABLE_WITH_TESTS)
     add_subdirectory(test)
   endif()
 
-  if (CTI_CONTINUABLE_WITH_EXAMPLES)
+  if(CTI_CONTINUABLE_WITH_EXAMPLES)
     add_subdirectory(examples)
   endif()
-endif ()
+endif()

Findcontinuable.cmake

@@ -0,0 +1,10 @@
+# Makes it possible to find continuable through find_package(continuable REQUIRED)
+# when this source directory was added to the CMake module path.
+# For instance it could be done through adding this to the CMakeLists.txt
+# file in the parent directory:
+# ```cmake
+# list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/continuable")
+# ```
+
+set(CTI_CONTINUABLE_IS_FIND_INCLUDED ON)
+include("${CMAKE_CURRENT_LIST_DIR}/CMakeLists.txt")

LICENSE.txt

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+Copyright (c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

Readme.md

@@ -1,443 +1,233 @@
-![](https://raw.githubusercontent.com/Naios/continuable/master/doc/slideshow.gif)
 
-[![](https://img.shields.io/badge/Version-2.0.0-0091EA.svg)](https://github.com/Naios/continuable/releases/tag/2.0.0) [![Build Status](https://travis-ci.org/Naios/continuable.svg?branch=master)](https://travis-ci.org/Naios/continuable) [![Build status](https://ci.appveyor.com/api/projects/status/328ta3r5x92f3byv/branch/master?svg=true)](https://ci.appveyor.com/project/Naios/continuable/branch/master) ![](https://img.shields.io/badge/License-MIT-00838F.svg) [![](https://img.shields.io/badge/Documentation-Doxygen-26A69A.svg)](https://naios.github.io/continuable/) [![](https://img.shields.io/badge/Try-online-4DB6AC.svg)](http://melpon.org/wandbox/permlink/xVM2szjDLEge3YLV)
+<p align="center">
+  <a href="https://naios.github.io/continuable/">
+    <img alt="Continuable" src="https://raw.githubusercontent.com/Naios/continuable/master/doc/slideshow.gif">
+  </a>
+</p>
+
+<p align="center">
+  <a href="https://naios.github.io/continuable/changelog.html#changelog-versions-4-0-0"><img alt="Current version" src="https://img.shields.io/badge/Version-4.0.0-0091EA.svg"></a>
+  <a href="https://ci.appveyor.com/project/Naios/continuable/branch/master"><img alt="AppVeyor CI status" src="https://ci.appveyor.com/api/projects/status/328ta3r5x92f3byv/branch/master?svg=true"></a>
+  <img alt="MIT Licensed" src="https://img.shields.io/badge/License-MIT-00838F.svg">
+  <a href="https://naios.github.io/continuable/"><img alt="Documentation" src="https://img.shields.io/badge/Documentation-Doxygen-26A69A.svg"></a>
+  <a href="https://wandbox.org/permlink/EDr7u2P5HXs2W6p1"><img alt="Try continuable online" src="https://img.shields.io/badge/Run-online-4DB6AC.svg"></a>
+  <a href="https://godbolt.org/g/iyE4Ww"><img alt="Compiler explorer" src="https://img.shields.io/badge/Compiler-explorer-58CEC2.svg"></a>
+</p>
 
 ------
 
+#### Continuable is a C++14 library that provides full support for:
 
-This library provides full feature support of:
+* lazy async continuation chaining based on callbacks (**then**) and expression templates, callbacks are wrapped nicely as **promises**.
+* **no enforced type-erasure** which means we need **less heap allocations** than comparable libraries, strictly following the **"don't pay for what you don't use"** principle.
+* support for *all*, *any* and *sequential* connections between continuables through expressive operator overloads **&&**, **||** and **>>** as well as free functions **when_all**, **when_any** and **when_seq**.
+* asynchronous **error handling** through **exceptions**, **error codes** and **user defined types**.
+* syntactic sugar for instance: **partial invocation**, **tuple unpacking**, `co_await` support and **executors**.
+* **encapsuled from any runtime**, larger framework or executors makes it possible to use continuable even in smaller or esoteric usage scenarios.
 
-* lazy async continuation chaining based on **callbacks** (*then*) and expression templates, callbacks are wrapped nicely as promises.
+------
-* **no enforced type-erasure** which means we need **less heap allocations**, strictly following the **"don't pay for what you don't use"** principle. 
+
-* support for **connections** between continuables through an **all, any or sequential** strategy through expressive operator overloads **&&**, **||** and **>>**.
+#### Getting started:
-* **error handling** through exceptions or custom types.
+
-* **syntactic sugar** for instance: **partial invocation**, **tuple unpacking** and **executors**.
+The [documentation](https://naios.github.io/continuable/) offers everything you need:
+* [Installation guide](https://naios.github.io/continuable/installation.html)
+* [Usage tutorial](https://naios.github.io/continuable/tutorial.html)
+* [Configuration explanation](https://naios.github.io/continuable/configuration.html)
+* [Changelog](https://naios.github.io/continuable/changelog.html)
 
 
+#### Issues and contributions
 
-## The basics
+Issue reports and questions are accepted through the Github issue tracker as well as pull requests.
+Every contribution is welcome! Don't hesitate to ask for help if you need any support
+in improving the implementation or if you have any troubles in using the library
 
+#### Quick Tour
 
-* Supply a continuable which is invoked lazily upon request:
+- **Create a continuable through `make_continuable` which returns a promise on invocation:**
   ```cpp
   auto http_request(std::string url) {
     return cti::make_continuable<std::string>([url = std::move(url)](auto&& promise) {
       // Perform the actual request through a different library,
       // resolve the promise upon completion of the task.
       promise.set_value("<html> ... </html>");
+      // or: promise.set_exception(std::make_exception_ptr(std::exception("Some error")));
+      // or: promise.set_canceled();
+    });
+  }
+
+  auto mysql_query(std::string query) {
+    return cti::make_continuable<result_set, bool>([url = std::move(url)](auto&& promise) {
+      //                         ^^^^^^^^^^^^^^ multiple result types
+    });
+  }
+
+  auto do_sth() {
+    return cti::make_continuable<void>([](auto&& promise) {
+      //                         ^^^^ no result at all
+    });
+  }
+
+  auto run_it() {
+    return async([] {
+      // Directly start with a handler
+    });
+  }
+
+  continuable<> run_it() { // With type erasure
+    return async([] {
 
-      // Or promise.set_exception(...);
     });
   }
   ```
-* Continue the continuation using `.then(...)` and `.fail(...)`, exceptions are passed to the first available handler:
 
+- **Attach your continuations through `then`, supports multiple results and partial handlers:**
   ```cpp
-  http_request("github.com")
+  mysql_query("SELECT `id`, `name` FROM `users`")
-    .then([] (std::string result) {
+    .then([](result_set users) {
-      // Do something...
+      // Return the next continuable to process ...
-      return http_request("travis-ci.org")
+      return mysql_query("SELECT `id` name FROM `sessions`");
     })
-    .then([] (std::string result) {
+    .then([](result_set sessions) {
-      // Handle the response from 'travis-ci.org'
+      // ... or pass multiple values to the next callback using tuples or pairs ...
+      return std::make_tuple(std::move(sessions), true);
+    })
+    .then([](result_set sessions, bool is_ok) {
+      // ... or pass a single value to the next callback ...
+      return 10;
+    })
+    .then([](auto value) {
+      //     ^^^^ Templated callbacks are possible too
+    })
+    // ... you may even pass continuables to the `then` method directly:
+    .then(mysql_query("SELECT * `statistics`"))
+    .then([](result_set result) {
+      // ...
+        return "Hi";
+    })
+    .then([] /*(std::string result) */ { // Handlers can accept a partial set of arguments{
+      // ...
+    });
+  ```
+
+- **Handle failures through `fail` or `next`:**
+  ```cpp
+  http_request("example.com")
+    .then([] {
+      throw std::exception("Some error");
     })
     .fail([] (std::exception_ptr ptr) {
-      try {
+      if (ptr) {
-        std::rethrow_exception(ptr);
+        try {
-      } catch(std::exception const& e) {
+          std::rethrow_exception(ptr);
-        // Handle the exception or error code here
+        } catch(std::exception const& e) {
+          // Handle the exception or error code here
+        }
       }
     });
   ```
-* Create connections between the continuables and use its compound result:
+
+- **Dispatch continuations through a specific executor** (possibly on a different thread or later)
+
   ```cpp
-  (http_request("github.com") && (http_request("travis-ci.org") || http_request("atom.io")))
+  auto executor = [](auto&& work) {
-    .then([](std::string github, std::string travis_or_atom) {
+    // Dispatch the work here, store it for later invocation or move it to another thread.
-      // The promise is called with the response of github and travis or atom.
+    std::forward<decltype(work)>(work)();
+  };
+
+  read_file("entries.csv")
+    .then([](Buffer buffer) {
+      // ...
+    }, executor);
+  //   ^^^^^^^^
+  ```
+
+- **Connect continuables through `when_all`, `when_any` or `when_seq`:**
+  ```cpp
+  // `all` of connections:
+  (http_request("github.com") && http_request("example.com") && http_request("wikipedia.org"))
+    .then([](std::string github, std::string example, std::string wikipedia) {
+      // The callback is called with the response of github,
+      // example and wikipedia.
+    });
+
+  // `any` of connections:
+  (http_request("github.com") || http_request("example.com") || http_request("wikipedia.org"))
+    .then([](std::string github_or_example_or_wikipedia) {
+      // The callback is called with the first response of either github,
+      // example or wikipedia.
+    });
+
+  // `sequence` of connections:
+  (http_request("github.com") >> http_request("example.com") >> http_request("wikipedia.org"))
+    .then([](std::string github, std::string example, std::string wikipedia) {
+      // The requests are invoked sequentially
+    });
+
+  // Mixed logical connections:
+  (http_request("github.com") && (http_request("example.com") || http_request("wikipedia.org")))
+    .then([](std::string github, std::string example_or_wikipedia) {
+      // The callback is called with the response of github for sure
+      // and the second parameter represents the response of example or wikipedia.
+    });
+
+  // There are helper functions for connecting continuables:
+  auto all = cti::when_all(http_request("github.com"), http_request("example.com"));
+  auto any = cti::when_any(http_request("github.com"), http_request("example.com"));
+  auto seq = cti::when_seq(http_request("github.com"), http_request("example.com"));
+  ```
+
+- **Deal with multiple result variables through `result` and `recover` from failures:**
+  ```cpp
+  make_exceptional_continuable<void>(std::make_exception_ptr(std::exception("Some error"))
+    .fail([] (std::exception_ptr ptr) {
+      return recover();
+    })
+    .then([] () -> result<> {
+      // We recovered from the failure and proceeding normally
+
+      // Will yield a default constructed exception type to signal cancellation
+      return cancel();
     });
   ```
 
+- **`promisify` your existing code or use the (asio) completion token integration:**
+  ```cpp
+  // Promisification of your existing code that accepts callbacks
+  auto async_resolve(std::string host, std::string service) {
+    return cti::promisify<asio::ip::udp::resolver::iterator>::from(
+        [&](auto&&... args) {
+          resolver_.async_resolve(std::forward<decltype(args)>(args)...);
+        },
+        std::move(host), std::move(service));
+  }
 
+  // (boost) asio completion token integration
+  asio::io_context io_context;
+  asio::steady_timer steady_timer(io_context);
 
-## Table of contents
+  steady_timer.expires_after(std::chrono::seconds(5));
+  steady_timer.async_wait(cti::use_continuable)
+    .then([] {
+      // Is called after 5s
+    });
+  ```
 
-- [Installation](#installation)
+- **C++20 Coroutine support:**
-    - [How-to use](#how-to-use)
-    - [Building the unit-tests](#building-the-unit-tests)
-- [Stability and version](#stability-and-version)
-- [Quick reference](#quick-reference)
-    - [Creating Continuables](#creating-continuables)
-    - [Chaining Continuables](#chaining-continuables)
-    - [Providing helper functions](#providing-helper-functions)
-    - [Error handling](#error-handling)
-    - [Connecting Continuables {all, any or sequential}](#connecting-continuables-all-any-or-sequential)
-    - [Partial argument application](#partial-argument-application)
-    - [Dispatching callbacks through a specific executor](#dispatching-callbacks-through-a-specific-executor)
-    - [Type erasure](#type-erasure)
-    - [Coroutines](#coroutines)
-    - [Future conversion](#future-conversion)
-- [Compatibility](#compatibility)
-- [License](#license)
 
+  (`co_await` and `co_return`) are supported by continuable when the underlying toolchain supports the TS. Currently this works in MSVC 2017 and Clang 5.0. You have to enable this capability through the `CTI_CONTINUABLE_WITH_AWAIT` define in CMake:
 
-## Installation
+  ```cpp
-
+  int i = co_await cti::make_continuable<int>([](auto&& promise) {
-### How-to use
+    promise.set_value(0);
-
-As mentioned earlier the library is header-only. There is a cmake project provided for simple setup:
-
-#### As git submodule
-
-```sh
-# Shell:
-git submodule add https://github.com/Naios/continuable.git
-```
-
-```cmake
-# CMake file:
-add_subdirectory(continuable)
-# continuable provides an interface target which makes it's
-# headers available to all projects using the continuable library.
-target_link_libraries(my_project continuable)
-```
-
-On POSIX platforms you are required to link your application against a corresponding thread library, otherwise `std::future's` won't work properly, this is done automatically by the provided CMake project.
-
-#### As CMake library
-
-Additionally the project exports a `continuable` target which is importable through CMake when installed:
-
-```sh
-mkdir build
-cd build
-cmake ..
-cmake --build . --target INSTALL --config Release
-```
-
-`CMakeLists.txt`:
-
-```cmake
-find_package(continuable REQUIRED)
-```
-
-### Building the unit-tests
-
-In order to build the unit tests clone the repository recursively with all submodules:
-
-```sh
-# Shell:
-git clone --recursive https://github.com/Naios/continuable.git
-```
-## Stability and version
-
-The library follows the rules of [semantic versioning](http://semver.org/), the API is kept stable across minor versions.
-
-The CI driven unit-tests are observed through the Clang sanitizers (asan, ubsan and lsan - when compiling with Clang) or Valgrind (when compiling with GCC).
-
-## Quick reference
-
-This chapter only overflies the functionality of the continuable library, the full documentation is located at https://naios.github.io/continuable/.
-
-### Creating Continuables 
-
-Create a continuable from a promise taking function:
-
-```c++
-#include <continuable/continuable-base.hpp>
-// ...
-
-auto void_continuable = cti::make_continuable<void>([](auto&& promise) {
-  //                                          ^^^^
-  
-  // Resolve the promise later when you have finished your work
-  promise.set_value();
-});
-
-auto str_continuable = cti::make_continuable<std::string>([](auto&& promise) {
-  //                                         ^^^^^^^^^^^
-  promise.set_value("Hello, World!");
-});
-```
-
-### Chaining Continuables
-
-Chain continuables together in order to build up an asynchronous call hierarchy:
-
-```c++
-mysql_query("SELECT `id`, `name` FROM `users`")
-  .then([](ResultSet users) {
-    // Return the next continuable to process ...
-    return mysql_query("SELECT `id` name FROM `sessions`");   
-  })
-  .then([](ResultSet sessions) {
-    // ... or pass multiple values to the next callback using tuples or pairs ...
-    return std::make_tuple(std::move(sessions), true);
-  })
-  .then([](ResultSet sessions, bool is_ok) {
-    // ... or pass a single value to the next callback ...
-    return 10;
-  })
-  .then([](auto value) {
-    //     ^^^^ Templated callbacks are possible too
-  })
-  // ... you may even pass continuables to the `then` method directly:
-  .then(mysql_query("SELECT * `statistics`"))
-  .then([](ResultSet result) {
-    // ...
   });
-```
+  ```
 
-> **Note:** The continuation chain is invoked when the object is destructed or the `done()` method is called.
 
-### Providing helper functions
+#### Appearances:
 
-Returning continuables from helper functions makes chaining simple and expressive:
+| [MeetingC++ 2018 Talk](https://naios.github.io/talks/2018-11-17-Meeting-C%2B%2B-Berlin/Continuable.pdf) |
-
+| :---: |
-```c++
+| [<img alt="Continuable MeetingC++" width="60%" src="https://img.youtube.com/vi/l6-spMA_x6g/0.jpg">](https://www.youtube.com/watch?v=l6-spMA_x6g)] |
-#include <continuable/continuable-base.hpp>
-// ...
-
-auto mysql_query(std::string query) {
-  return cti::make_continuable<ResultSet>([query = std::move(query)](auto&& promise) mutable {
-    // Pass the callback to the handler which calls the callback when finished.
-    // Every function accepting callbacks works with continuables.
-    mysql_handle_async_query(std::move(query),
-                             std::forward<decltype(promise)>(promise));
-  });
-}
-
-// You may use the helper function like you would normally do,
-// without using the support methods of the continuable.
-mysql_query("DELETE FROM `users` WHERE `id` = 27361");
-
-// Or using chaining to handle the result which is covered in the documentation.
-mysql_query("SELECT `id`, `name` FROM users")
-  .then([](ResultSet result) {
-    // ...
-  });
-```
-
-### Error handling
-
-Continuables support asynchronous error handling through exceptions or custom error types. 
-
-The error type will be **`std::exception_ptr`** except if one of the following definition is defined:
-- **`CONTINUABLE_WITH_CUSTOM_ERROR_TYPE`**:  Define this to use a user defined error type.
-- **`CONTINUABLE_WITH_NO_EXCEPTIONS`**: Define this to use **`std::error_condition`** as error type and to disable exception support. When exceptions are disabled this definition is set automatically.
-
-Resolving a promise through an error will skip all following result handlers attached through **`then`**:
-
-```cpp
-auto get_bad_continuable(std::exception const& e) {
-  return cti::make_continuable<void>([=] (auto&& promise) {
-    try {
-     throw e;
-    } catch(...) {
-      promise.set_exception(std::current_exception());
-    }
-  });
-}
-```
-
-You may handle the exception as following:
-
-```cpp
-get_bad_continuable()
-  .then([] {
-    // ... never invoked
-  })
-  .then([] {
-    // ... never invoked as well
-  })
-  .fail([] (std::exception_ptr e) {
-    try {
-      std::rethrow_exception(e);
-    } catch(std::exception const& e) {
-      // Handle the exception here
-    }
-  });
-```
-
-### Connecting Continuables {all, any or sequential}
-
-Continuables provide the operators **&&** and **||** for logical connection:
-
-* **&&** invokes the final callback with the compound result of all connected continuables, the continuables were invoked in parallel.
-* **||** invokes the final callback once with the first result which becomes available.
-* **>\>** invokes the final callback with the compound result of all connected continuables but the continuations were invokes sequentially.
-
-```C++
-auto http_request(std::string url) {
-  return cti::make_continuable<std::string>([](auto&& promise) {
-    promise.set_value("<html>...</html>");
-  });
-}
-
-// `all` of connections:
-(http_request("github.com") && http_request("travis-ci.org") && http_request("atom.io"))
-  .then([](std::string github, std::string travis, std::string atom) {
-    // The callback is called with the response of github, travis and atom.
-  });
-
-// `any` of connections:
-(http_request("github.com") || http_request("travis-ci.org") || http_request("atom.io"))
-  .then([](std::string github_or_travis_or_atom) {
-    // The callback is called with the first response of either github, travis or atom.
-  });
-
-// `sequence` of connections:
-(http_request("github.com") >> http_request("travis-ci.org") >> http_request("atom.io"))
-  .then([](std::string github, std::string travis, std::string atom) {
-    // The requests are invoked sequentially
-  });
-
-// mixed logical connections:
-(http_request("github.com") && (http_request("travis-ci.org") || http_request("atom.io")))
-  .then([](std::string github, std::string travis_or_atom) {
-    // The callback is called with the response of github for sure
-    // and the second parameter represents the response of travis or atom.
-  });
-
-// There are helper functions for connecting continuables:
-auto all = cti::when_all(http_request("github.com"), http_request("travis-ci.org"));
-auto any = cti::when_any(http_request("github.com"), http_request("travis-ci.org"));
-auto seq = cti::when_seq(http_request("github.com"), http_request("travis-ci.org"));
-```
-
-> **Note:** Logical connections are ensured to be **thread-safe** and **wait-free** by library design (when assuming that *std::call_once* is wait-free - which depends on the toolchain).
-
-### Partial argument application
-
-The callback is called only with the arguments it's accepting:
-
-```c++
-(http_request("github.com") && read_file("entries.csv"))
-  .then([] {
-    // ^^^^^^ The original signature was <std::string, Buffer>,
-    // however, the callback is only invoked with the amount of
-    // arguments it's accepting.
-  });
-```
-
-### Dispatching callbacks through a specific executor
-
-Dispatching a callback through a specific executor is supported through through the second argument of `then()`:
-
-```c++
-auto executor = [](auto&& work) {
-  // Dispatch the work here, store it for later invocation or move it to another thread.
-  std::forward<decltype(work)>(work)();
-};
-
-read_file("entries.csv")
-  .then([](Buffer buffer) {
-    // ...
-  }, executor);
-//   ^^^^^^^^
-```
-
-### Type erasure
-
-The library was designed in order to avoid type-erasure until really needed. Thus we provide traits to create an alias to a continuable using the **type-erasure backend of your choice**. All templated functors providing a call operator may be used as a backend (*std::function* for instance).
-
-The library provides aliases for using my [function2 library](https://github.com/Naios/function2) as backend which provides efficient and qualifier correct function wrappers for copyable and non-copyable objects.
-
-```c++
-#include <continuable/continuable.hpp>
-
-cti::unique_continuable<int, std::string> unique =
-      cti::make_continuable([value = std::make_unique<int>(0)](auto&& promise) {
-
-  // The use of non copyable objects is possible by design if
-  // the type erasure backend supports it.
-  promise.set_value(*value, "Hello, World!");
-});
-
-std::move(unique).then([](int i) {
-  // ...
-});
-```
-
-We could also think about using  `std::future` as backend but this is even worse then using `std::function` because usually there is, even more, type erasure and allocations involved.
-Additionally `std::function` doesn't provide support for multiple function overloads
-
-### Coroutines
-
-Since version 2.0.0 coroutines (`co_await` and `co_return`) are supported by continuables when the underlying toolchain supports the TS. Currently this works in MSVC 2017 and Clang 5.0.
-You have to enable this capability through the `CTI_CONTINUABLE_WITH_AWAIT` define in CMake.
-
-```c++
-int i = co_await cti::make_continuable<int>([](auto&& promise) {
-  promise.set_value(0);
-});
-```
-
-### Future conversion
-
-The library is capable of converting (*futurizing*) every continuable into a fitting **std::future** through the `continuable<...>::futurize()` method.:
-
-```c++
-std::future<std::string> future = http_request("github.com")
-  .then([](std::string response) {
-    // Do sth...
-    return http_request("travis-ci.org") || http_request("atom.io");
-  })
-  .apply(cti::transforms::futurize());
-// ^^^^^^^^
-
-std::future<std::tuple<std::string, std::string>> future =
-  (http_request("travis-ci.org") && http_request("atom.io"))
-    .apply(cti::transforms::futurize());
-```
-
-> **Note:** See the [doxygen documentation](https://naios.github.io/continuable/) for detailed information about the return type of `futurize()`.
-
-## Compatibility
-
-Tested & compatible with:
-
-- Visual Studio 2017+ Update 2
-- Clang 5.0+
-- GCC 6.0+
-
-Although the build is observed with the latest toolchains earlier ones might work.
-
-The library only depends on the standard library when using the `continuable/continuable-base.hpp` header, which provides the basic continuation logic.
-
-> **Note:** On Posix: don't  forget to **link a corresponding thread library** into your application otherwise `std::future's` won't work `(-pthread)`  when using future based transforms.
-
-## License
-
-The continuable library is licensed under the MIT License:
-
-```
-/**
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v2.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-```
 
+.

appveyor.yml

@@ -1,13 +1,17 @@
 image:
   - Visual Studio 2017
+  - Visual Studio 2019
 
 environment:
   matrix:
-    - WITH_NO_EXCEPTIONS: OFF
+  - WITH_NO_EXCEPTIONS: OFF
-    - WITH_NO_EXCEPTIONS: ON
+    WITH_CPP_LATEST: OFF
-
+  - WITH_NO_EXCEPTIONS: ON
-configuration:
+    WITH_CPP_LATEST: OFF
-  - Debug
+  - WITH_NO_EXCEPTIONS: OFF
+    WITH_CPP_LATEST: ON
+  - WITH_NO_EXCEPTIONS: ON
+    WITH_CPP_LATEST: ON
 
 platform:
   - x64
@@ -20,17 +24,20 @@ clone_script:
 
 before_build:
   - cmd: >
-         cmake -H. -Bbuild -A%PLATFORM%
+     cmake -H. -Bbuild -A%PLATFORM%
-         -DCTI_CONTINUABLE_WITH_NO_EXCEPTIONS=%WITH_NO_EXCEPTIONS%
+     -DCTI_CONTINUABLE_WITH_NO_EXCEPTIONS=%WITH_NO_EXCEPTIONS%
-         -DCTI_CONTINUABLE_WITH_AWAIT=ON
+     -DCTI_CONTINUABLE_WITH_EXPERIMENTAL_COROUTINE=ON
+     -DCTI_CONTINUABLE_WITH_CPP_LATEST=%WITH_CPP_LATEST%
 
 build_script:
-  - cmd: cmake --build build --config %CONFIGURATION% --target ALL_BUILD -- /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" /verbosity:minimal /maxcpucount:2 /nologo
+  - cmd: cmake --build build --config Debug --target ALL_BUILD -- /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" /verbosity:minimal /maxcpucount:2 /nologo
-  - cmd: cmake --build build --config %CONFIGURATION% --target PACKAGE -- /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" /verbosity:minimal /maxcpucount:2 /nologo
+  - cmd: cmake --build build --config Debug --target ALL_BUILD -- /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" /verbosity:minimal /maxcpucount:2 /nologo
+  - cmd: cmake --build build --config Release --target PACKAGE -- /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" /verbosity:minimal /maxcpucount:2 /nologo
 
 test_script:
   - cmd: cd build
-  - cmd: ctest -C %CONFIGURATION% -V .
+  - cmd: ctest -C Debug -V .
+  - cmd: ctest -C Release -V .
 
 artifacts:
   - path: 'build/*.zip'

cmake/CMakeLists.txt

@@ -1,5 +1,5 @@
 
-# Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+# Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files(the "Software"), to deal
@@ -13,7 +13,7 @@
 #
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

cmake/compiler/clang.cmake

@@ -1,5 +1,5 @@
 
-# Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+# Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files(the "Software"), to deal
@@ -13,7 +13,7 @@
 #
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

cmake/compiler/gcc.cmake

@@ -1,5 +1,5 @@
 
-# Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+# Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files(the "Software"), to deal
@@ -13,7 +13,7 @@
 #
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

cmake/compiler/msvc.cmake

@@ -1,5 +1,5 @@
 
-# Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+# Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files(the "Software"), to deal
@@ -13,7 +13,7 @@
 #
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -31,9 +31,18 @@ if (PLATFORM EQUAL 64)
       -D_WIN64)
 endif()
 
+if (CTI_CONTINUABLE_WITH_CONCURRENT_JOBS)
+  target_compile_options(continuable-features-flags
+    INTERFACE
+      /MP${CTI_CONTINUABLE_WITH_CONCURRENT_JOBS})
+else()
+  target_compile_options(continuable-features-flags
+    INTERFACE
+      /MP)
+endif()
+
 target_compile_options(continuable-features-flags
   INTERFACE
-    /MP
     /bigobj
     /permissive-)
 
@@ -41,6 +50,12 @@ target_compile_options(continuable-features-warnings
   INTERFACE
     /W4)
 
+if (NOT CTI_CONTINUABLE_WITH_CPP_LATEST)
+  target_compile_options(continuable-features-flags
+    INTERFACE
+      /std:c++14)
+endif()
+
 if (CTI_CONTINUABLE_WITH_NO_EXCEPTIONS)
   target_compile_definitions(continuable-features-noexcept
     INTERFACE

cmake/config.cmake.in

@@ -0,0 +1,7 @@
+set(@PROJECT_NAME@_VERSION @PROJECT_VERSION@)
+
+@PACKAGE_INIT@
+
+include("${CMAKE_CURRENT_LIST_DIR}/@PROJECT_NAME@Targets.cmake")
+
+check_required_components(@PROJECT_NAME@)

cmake/configure_compiler.cmake

@@ -1,5 +1,5 @@
 
-# Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+# Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files(the "Software"), to deal
@@ -13,7 +13,7 @@
 #
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -21,12 +21,12 @@
 
 # Select the compiler specific cmake file
 set(MSVC_ID "MSVC")
-if (${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
+if (${CMAKE_CXX_COMPILER_ID} MATCHES "(Apple)?Clang")
-  include(${CMAKE_SOURCE_DIR}/cmake/compiler/clang.cmake)
+  include(${PROJECT_SOURCE_DIR}/cmake/compiler/clang.cmake)
 elseif (${CMAKE_CXX_COMPILER_ID} STREQUAL "GNU")
-  include(${CMAKE_SOURCE_DIR}/cmake/compiler/gcc.cmake)
+  include(${PROJECT_SOURCE_DIR}/cmake/compiler/gcc.cmake)
 elseif (${CMAKE_CXX_COMPILER_ID} STREQUAL ${MSVC_ID})
-  include(${CMAKE_SOURCE_DIR}/cmake/compiler/msvc.cmake)
+  include(${PROJECT_SOURCE_DIR}/cmake/compiler/msvc.cmake)
 else()
   message(FATAL_ERROR "Unknown compiler!")
 endif()

cmake/configure_macros.cmake

@@ -1,5 +1,5 @@
 
-# Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+# Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files(the "Software"), to deal
@@ -13,10 +13,10 @@
 #
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-include(${CMAKE_SOURCE_DIR}/cmake/macros/group_sources.cmake)
+include(${PROJECT_SOURCE_DIR}/cmake/macros/group_sources.cmake)

cmake/macros/group_sources.cmake

@@ -1,5 +1,5 @@
 
-# Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+# Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files(the "Software"), to deal
@@ -13,46 +13,48 @@
 #
 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
 set(WITH_SOURCE_TREE "hierarchical")
-macro(group_sources dir)
+macro(group_sources)
   # Skip this if WITH_SOURCE_TREE is not set (empty string).
   if (NOT ${WITH_SOURCE_TREE} STREQUAL "")
-    # Include all header and c files
+    foreach(dir ${ARGN})
-    file(GLOB_RECURSE elements RELATIVE ${dir} *.h *.hpp *.inl *.inc *.c *.cpp *.cc)
+      # Include all header and c files
+      file(GLOB_RECURSE elements RELATIVE ${dir} ${dir}/*)
 
-    foreach(element ${elements})
+      foreach(element ${elements})
-      # Extract filename and directory
+        # Extract filename and directory
-      get_filename_component(element_name ${element} NAME)
+        get_filename_component(element_name ${element} NAME)
-      get_filename_component(element_dir ${element} DIRECTORY)
+        get_filename_component(element_dir ${element} DIRECTORY)
 
-      if (NOT ${element_dir} STREQUAL "")
+        if (NOT ${element_dir} STREQUAL "")
-        # If the file is in a subdirectory use it as source group.
+          # If the file is in a subdirectory use it as source group.
-        if (${WITH_SOURCE_TREE} STREQUAL "flat")
+          if (${WITH_SOURCE_TREE} STREQUAL "flat")
-          # Build flat structure by using only the first subdirectory.
+            # Build flat structure by using only the first subdirectory.
-          string(FIND ${element_dir} "/" delemiter_pos)
+            string(FIND ${element_dir} "/" delemiter_pos)
-          if (NOT ${delemiter_pos} EQUAL -1)
+            if (NOT ${delemiter_pos} EQUAL -1)
-            string(SUBSTRING ${element_dir} 0 ${delemiter_pos} group_name)
+              string(SUBSTRING ${element_dir} 0 ${delemiter_pos} group_name)
-            source_group("${group_name}" FILES ${dir}/${element})
+              source_group("${group_name}" FILES ${dir}/${element})
+            else()
+              # Build hierarchical structure.
+              # File is in root directory.
+              source_group("${element_dir}" FILES ${dir}/${element})
+            endif()
           else()
-            # Build hierarchical structure.
+            # Use the full hierarchical structure to build source_groups.
-            # File is in root directory.
+            string(REPLACE "/" "\\" group_name ${element_dir})
-            source_group("${element_dir}" FILES ${dir}/${element})
+            source_group("${group_name}" FILES ${dir}/${element})
           endif()
         else()
-          # Use the full hierarchical structure to build source_groups.
+          # If the file is in the root directory, place it in the root source_group.
-          string(REPLACE "/" "\\" group_name ${element_dir})
+          source_group("\\" FILES ${dir}/${element})
-          source_group("${group_name}" FILES ${dir}/${element})
         endif()
-      else()
+      endforeach()
-        # If the file is in the root directory, place it in the root source_group.
-        source_group("\\" FILES ${dir}/${element})
-      endif()
     endforeach()
   endif()
 endmacro()

conanfile.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from conans import ConanFile, tools
+
+def get_version():
+    git = tools.Git()
+    try:
+        return git.run("describe --tags --abbrev=0")
+    except:
+        return None
+
+class ContinuableConan(ConanFile):
+    name = "continuable"
+    version = get_version()
+    license = "MIT"
+    url = "https://github.com/Naios/continuable"
+    author = "Denis Blank (denis.blank@outlook.com)"
+    description = "C++14 asynchronous allocation aware futures"
+    homepage = "https://naios.github.io/continuable/"
+    no_copy_source = True
+    scm = {
+        "type": "git",
+        "url": "auto",
+        "revision": "auto"
+    }
+
+    def package(self):
+        self.copy("LICENSE.txt", "licenses")
+        self.copy("include/*.hpp")
+        self.copy("include/*.inl")
+
+    def package_id(self):
+        self.info.header_only()
+
+    def requirements(self):
+        self.requires("function2/4.0.0@naios/stable")

dep/CMakeLists.txt

@@ -1,17 +1,25 @@
-if(NOT TARGET function2)
+if(NOT TARGET function2::function2)
   add_subdirectory(function2)
 endif()
 
-if (CTI_CONTINUABLE_WITH_TESTS OR CTI_CONTINUABLE_WITH_EXAMPLES)
+if (CTI_CONTINUABLE_WITH_TESTS OR CTI_CONTINUABLE_WITH_BENCHMARKS)
   if(NOT TARGET gtest)
     add_subdirectory(googletest)
   endif()
+endif()
 
-  if(NOT TARGET cxx_function)
+if (CTI_CONTINUABLE_WITH_EXAMPLES)
-    add_subdirectory(cxx_function)
-  endif()
-
   if(NOT TARGET asio)
     add_subdirectory(asio)
   endif()
 endif()
+
+if (CTI_CONTINUABLE_WITH_BENCHMARKS)
+  if(NOT TARGET benchmark)
+    add_subdirectory(benchmark)
+  endif()
+
+  if(NOT TARGET boost)
+    add_subdirectory(boost)
+  endif()
+endif()

dep/asio/CMakeLists.txt

@@ -1,9 +1,11 @@
 add_library(asio STATIC
-  ${CMAKE_CURRENT_LIST_DIR}/asio/asio/src/asio.cpp)
+  ${CMAKE_CURRENT_LIST_DIR}/asio/asio/src/asio.cpp
+  ${CMAKE_CURRENT_LIST_DIR}/include/boost/throw_exception.hpp)
 
 target_include_directories(asio
   PUBLIC
-    ${CMAKE_CURRENT_LIST_DIR}/asio/asio/include)
+    ${CMAKE_CURRENT_LIST_DIR}/asio/asio/include
+    ${CMAKE_CURRENT_LIST_DIR}/include)
 
 target_compile_definitions(asio
   PUBLIC
@@ -11,6 +13,15 @@ target_compile_definitions(asio
     -DASIO_SEPARATE_COMPILATION=1
     -DASIO_NO_TYPEID=1)
 
+if (CTI_CONTINUABLE_WITH_NO_EXCEPTIONS)
+  target_compile_definitions(asio
+    PUBLIC
+      -DASIO_NO_EXCEPTIONS=1
+      -DASIO_HAS_BOOST_THROW_EXCEPTION=1)
+
+  message(STATUS "ASIO: Disabled exceptions")
+endif()
+
 if(WIN32)
 target_compile_definitions(asio
   PUBLIC

dep/asio/asio

@@ -1 +1 @@
-Subproject commit 230c0d2ae035c5ce1292233fcab03cea0d341264
+Subproject commit 6c054e98f3f53352d12b6cd46d63b6d404cc044b

dep/asio/include/boost/throw_exception.hpp

@@ -0,0 +1,47 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_BOOST_THROW_EXCEPTION_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_BOOST_THROW_EXCEPTION_HPP_INCLUDED
+
+#if defined(ASIO_STANDALONE) && defined(ASIO_NO_EXCEPTIONS)
+#  include <cstdio>
+#  include <cstdlib>
+
+namespace boost {
+template <typename Exception>
+void throw_exception(Exception const& e) {
+  puts(e.what());
+  std::abort();
+}
+} // namespace boost
+#endif
+
+#endif //  CONTINUABLE_DETAIL_BOOST_THROW_EXCEPTION_HPP_INCLUDED

dep/benchmark/CMakeLists.txt

@@ -0,0 +1,9 @@
+set(BENCHMARK_ENABLE_TESTING OFF)
+if (CTI_CONTINUABLE_WITHOUT_EXCEPTIONS)
+  set(BENCHMARK_ENABLE_EXCEPTIONS OFF)
+else()
+  set(BENCHMARK_ENABLE_EXCEPTIONS ON)
+endif()
+set(BENCHMARK_ENABLE_INSTALL OFF)
+set(BENCHMARK_ENABLE_GTEST_TESTS OFF)
+add_subdirectory(benchmark)

dep/benchmark/benchmark

@@ -0,0 +1 @@
+Subproject commit b874e72208b6e21b62287942e5e3b11f6630107f

dep/boost/CMakeLists.txt

@@ -0,0 +1,43 @@
+if(WIN32)
+  if(CMAKE_SIZEOF_VOID_P MATCHES 8)
+    set(PLATFORM 64)
+  else()
+    set(PLATFORM 32)
+  endif()
+
+  if(DEFINED ENV{BOOST_ROOT})
+    set(BOOST_ROOT $ENV{BOOST_ROOT})
+    set(BOOST_LIBRARYDIR ${BOOST_ROOT}/lib${PLATFORM}-msvc-14.1)
+  endif()
+
+  set(Boost_USE_STATIC_LIBS ON)
+  set(Boost_USE_MULTITHREADED ON)
+  set(Boost_USE_STATIC_RUNTIME OFF)
+endif()
+
+find_package(Boost 1.68 REQUIRED
+  COMPONENTS
+    system
+    iostreams
+    thread)
+
+if (${Boost_FOUND})
+  add_library(boost INTERFACE)
+
+  target_link_libraries(boost
+    INTERFACE
+      Boost::system
+      Boost::iostreams
+      Boost::thread)
+
+  target_compile_definitions(boost
+    INTERFACE
+      BOOST_ALL_NO_LIB
+      BOOST_ASIO_DISABLE_BOOST_DATE_TIME
+      BOOST_ASIO_DISABLE_BOOST_REGEX
+      BOOST_RANGE_ENABLE_CONCEPT_ASSERT=0
+      BOOST_THREAD_PROVIDES_FUTURE
+      BOOST_THREAD_PROVIDES_FUTURE_CONTINUATION
+      BOOST_FILESYSTEM_NO_DEPRECATED
+      BOOST_THREAD_VERSION=4)
+endif()

dep/cxx_function/CMakeLists.txt

@@ -1,5 +0,0 @@
-add_library(cxx_function INTERFACE)
-
-target_include_directories(cxx_function
-  INTERFACE
-    "${CMAKE_CURRENT_LIST_DIR}")

dep/cxx_function/cxx_function

@@ -1 +0,0 @@
-Subproject commit c12ed6e2da0c05ebc7bac30cdd260f152cb565a1

dep/function2/function2

@@ -1 +1 @@
-Subproject commit 8611ae3b0e2414427bf0381bd94085ca3175479b
+Subproject commit 3a0746bf5f601dfed05330aefcb6854354fce07d

dep/googletest/CMakeLists.txt

@@ -1,3 +1,4 @@
+if(ON)
 add_library(gtest STATIC
   ${CMAKE_CURRENT_LIST_DIR}/googletest/googletest/src/gtest-all.cc)
 
@@ -42,3 +43,10 @@ target_include_directories(gmock
     ${CMAKE_CURRENT_LIST_DIR}/googletest/googlemock
   PUBLIC
     ${CMAKE_CURRENT_LIST_DIR}/googletest/googlemock/include)
+
+else()
+set(BUILD_GTEST ON)
+set(BUILD_GMOCK OFF)
+set(INSTALL_GTEST OFF)
+add_subdirectory(googletest)
+endif()

dep/googletest/googletest

@@ -1 +1 @@
-Subproject commit ac34e6c950925df7165e626becd3f9d64dcd584b
+Subproject commit f2fb48c3b3d79a75a88a99fba6576b25d42ec528

doc/CMakeLists.txt

@@ -1 +0,0 @@
-add_subdirectory(code)

doc/Doxyfile

@@ -1,4 +1,4 @@
-# Doxyfile 1.8.10
+# Doxyfile 1.8.14
 
 # This file describes the settings to be used by the documentation system
 # doxygen (www.doxygen.org) for a project.
@@ -20,8 +20,8 @@
 # This tag specifies the encoding used for all characters in the config file
 # that follow. The default is UTF-8 which is also the encoding used for all text
 # before the first occurrence of this tag. Doxygen uses libiconv (or the iconv
-# built into libc) for the transcoding. See http://www.gnu.org/software/libiconv
+# built into libc) for the transcoding. See
-# for the list of possible encodings.
+# https://www.gnu.org/software/libiconv/ for the list of possible encodings.
 # The default value is: UTF-8.
 
 DOXYFILE_ENCODING      = UTF-8
@@ -38,13 +38,13 @@ PROJECT_NAME           = Continuable
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 
+PROJECT_NUMBER         = 4.1.0
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
 # quick idea about the purpose of the project. Keep the description short.
 
-PROJECT_BRIEF          = "Async C++14 platform independent continuation chainer providing light and allocation aware futures"
+PROJECT_BRIEF          = "C++14 asynchronous allocation aware futures"
 
 # With the PROJECT_LOGO tag one can specify a logo or an icon that is included
 # in the documentation. The maximum height of the logo should not exceed 55
@@ -303,6 +303,15 @@ EXTENSION_MAPPING      =
 
 MARKDOWN_SUPPORT       = YES
 
+# When the TOC_INCLUDE_HEADINGS tag is set to a non-zero value, all headings up
+# to that level are automatically included in the table of contents, even if
+# they do not have an id attribute.
+# Note: This feature currently applies only to Markdown headings.
+# Minimum value: 0, maximum value: 99, default value: 0.
+# This tag requires that the tag MARKDOWN_SUPPORT is set to YES.
+
+TOC_INCLUDE_HEADINGS   = 0
+
 # When enabled doxygen tries to link words that correspond to documented
 # classes, or namespaces to their corresponding documentation. Such a link can
 # be prevented in individual cases by putting a % sign in front of the word or
@@ -328,7 +337,7 @@ BUILTIN_STL_SUPPORT    = NO
 CPP_CLI_SUPPORT        = NO
 
 # Set the SIP_SUPPORT tag to YES if your project consists of sip (see:
-# http://www.riverbankcomputing.co.uk/software/sip/intro) sources only. Doxygen
+# https://www.riverbankcomputing.com/software/sip/intro) sources only. Doxygen
 # will parse them like normal C++ but will assume all classes use public instead
 # of private inheritance when no explicit protection keyword is present.
 # The default value is: NO.
@@ -614,19 +623,19 @@ STRICT_PROTO_MATCHING  = NO
 # list. This list is created by putting \todo commands in the documentation.
 # The default value is: YES.
 
-GENERATE_TODOLIST      = YES
+GENERATE_TODOLIST      = NO
 
 # The GENERATE_TESTLIST tag can be used to enable (YES) or disable (NO) the test
 # list. This list is created by putting \test commands in the documentation.
 # The default value is: YES.
 
-GENERATE_TESTLIST      = YES
+GENERATE_TESTLIST      = NO
 
 # The GENERATE_BUGLIST tag can be used to enable (YES) or disable (NO) the bug
 # list. This list is created by putting \bug commands in the documentation.
 # The default value is: YES.
 
-GENERATE_BUGLIST       = YES
+GENERATE_BUGLIST       = NO
 
 # The GENERATE_DEPRECATEDLIST tag can be used to enable (YES) or disable (NO)
 # the deprecated list. This list is created by putting \deprecated commands in
@@ -671,7 +680,7 @@ SHOW_FILES             = YES
 # Folder Tree View (if specified).
 # The default value is: YES.
 
-SHOW_NAMESPACES        = NO
+SHOW_NAMESPACES        = YES
 
 # The FILE_VERSION_FILTER tag can be used to specify a program or script that
 # doxygen should invoke to get the current version for each file (typically from
@@ -699,7 +708,7 @@ LAYOUT_FILE            =
 # The CITE_BIB_FILES tag can be used to specify one or more bib files containing
 # the reference definitions. This must be a list of .bib files. The .bib
 # extension is automatically appended if omitted. This requires the bibtex tool
-# to be installed. See also http://en.wikipedia.org/wiki/BibTeX for more info.
+# to be installed. See also https://en.wikipedia.org/wiki/BibTeX for more info.
 # For LaTeX the style of the bibliography can be controlled using
 # LATEX_BIB_STYLE. To use this feature you need bibtex and perl available in the
 # search path. See also \cite for info how to create references.
@@ -749,6 +758,12 @@ WARN_IF_DOC_ERROR      = YES
 
 WARN_NO_PARAMDOC       = NO
 
+# If the WARN_AS_ERROR tag is set to YES then doxygen will immediately stop when
+# a warning is encountered.
+# The default value is: NO.
+
+WARN_AS_ERROR          = NO
+
 # The WARN_FORMAT tag determines the format of the warning messages that doxygen
 # can produce. The string should contain the $file, $line, and $text tags, which
 # will be replaced by the file and line number from which the warning originated
@@ -775,13 +790,13 @@ WARN_LOGFILE           =
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = ../../include \
+INPUT                  = ../include \
-                         ../Index.md
+                         ../doc
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses
 # libiconv (or the iconv built into libc) for the transcoding. See the libiconv
-# documentation (see: http://www.gnu.org/software/libiconv) for the list of
+# documentation (see: https://www.gnu.org/software/libiconv/) for the list of
 # possible encodings.
 # The default value is: UTF-8.
 
@@ -798,8 +813,8 @@ INPUT_ENCODING         = UTF-8
 # If left blank the following patterns are tested:*.c, *.cc, *.cxx, *.cpp,
 # *.c++, *.java, *.ii, *.ixx, *.ipp, *.i++, *.inl, *.idl, *.ddl, *.odl, *.h,
 # *.hh, *.hxx, *.hpp, *.h++, *.cs, *.d, *.php, *.php4, *.php5, *.phtml, *.inc,
-# *.m, *.markdown, *.md, *.mm, *.dox, *.py, *.f90, *.f, *.for, *.tcl, *.vhd,
+# *.m, *.markdown, *.md, *.mm, *.dox, *.py, *.pyw, *.f90, *.f95, *.f03, *.f08,
-# *.vhdl, *.ucf, *.qsf, *.as and *.js.
+# *.f, *.for, *.tcl, *.vhd, *.vhdl, *.ucf and *.qsf.
 
 FILE_PATTERNS          = *.c \
                          *.cc \
@@ -843,6 +858,7 @@ FILE_PATTERNS          = *.c \
                          *.ucf \
                          *.qsf \
                          *.as \
+                         *.dox \
                          *.js
 
 # The RECURSIVE tag can be used to specify whether or not subdirectories should
@@ -858,9 +874,9 @@ RECURSIVE              = YES
 # Note that relative paths are relative to the directory from which doxygen is
 # run.
 
-EXCLUDE                = ../../dep \
+EXCLUDE                = ../dep \
-                         ../../test \
+                         ../test \
-                         ../../examples
+                         ../examples
 
 # The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
 # directories that are symbolic links (a Unix file system feature) are excluded
@@ -929,6 +945,10 @@ IMAGE_PATH             =
 # Note that the filter must not add or remove lines; it is applied before the
 # code is scanned, but not when the output code is generated. If lines are added
 # or removed, the anchors will not be placed correctly.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# properly processed by doxygen.
 
 INPUT_FILTER           = 
 
@@ -938,6 +958,10 @@ INPUT_FILTER           =
 # (like *.cpp=my_cpp_filter). See INPUT_FILTER for further information on how
 # filters are used. If the FILTER_PATTERNS tag is empty or if none of the
 # patterns match the file name, INPUT_FILTER is applied.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# properly processed by doxygen.
 
 FILTER_PATTERNS        = 
 
@@ -961,7 +985,7 @@ FILTER_SOURCE_PATTERNS =
 # (index.html). This can be useful if you have a project on for instance GitHub
 # and want to reuse the introduction page also for the doxygen output.
 
-USE_MDFILE_AS_MAINPAGE = Index.md
+USE_MDFILE_AS_MAINPAGE = 
 
 #---------------------------------------------------------------------------
 # Configuration options related to source browsing
@@ -1022,7 +1046,7 @@ SOURCE_TOOLTIPS        = YES
 # If the USE_HTAGS tag is set to YES then the references to source code will
 # point to the HTML generated by the htags(1) tool instead of doxygen built-in
 # source browser. The htags tool is part of GNU's global source tagging system
-# (see http://www.gnu.org/software/global/global.html). You will need version
+# (see https://www.gnu.org/software/global/global.html). You will need version
 # 4.8.6 or higher.
 #
 # To use it do the following:
@@ -1055,7 +1079,7 @@ VERBATIM_HEADERS       = YES
 # rich C++ code for which doxygen's built-in parser lacks the necessary type
 # information.
 # Note: The availability of this option depends on whether or not doxygen was
-# compiled with the --with-libclang option.
+# generated with the -Duse-libclang=ON option for CMake.
 # The default value is: NO.
 
 CLANG_ASSISTED_PARSING = NO
@@ -1068,6 +1092,17 @@ CLANG_ASSISTED_PARSING = NO
 
 CLANG_OPTIONS          = 
 
+# If clang assisted parsing is enabled you can provide the clang parser with the
+# path to the compilation database (see:
+# http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html) used when the files
+# were built. This is equivalent to specifying the "-p" option to a clang tool,
+# such as clang-check. These options will then be pased to the parser.
+# Note: The availability of this option depends on whether or not doxygen was
+# generated with the -Duse-libclang=ON option for CMake.
+# The default value is: 0.
+
+CLANG_COMPILATION_DATABASE_PATH= 0
+
 #---------------------------------------------------------------------------
 # Configuration options related to the alphabetical class index
 #---------------------------------------------------------------------------
@@ -1186,7 +1221,7 @@ HTML_EXTRA_FILES       =
 # The HTML_COLORSTYLE_HUE tag controls the color of the HTML output. Doxygen
 # will adjust the colors in the style sheet and background images according to
 # this color. Hue is specified as an angle on a colorwheel, see
-# http://en.wikipedia.org/wiki/Hue for more information. For instance the value
+# https://en.wikipedia.org/wiki/Hue for more information. For instance the value
 # 0 represents red, 60 is yellow, 120 is green, 180 is cyan, 240 is blue, 300
 # purple, and 360 is red again.
 # Minimum value: 0, maximum value: 359, default value: 220.
@@ -1222,6 +1257,17 @@ HTML_COLORSTYLE_GAMMA  = 80
 
 HTML_TIMESTAMP         = NO
 
+# If the HTML_DYNAMIC_MENUS tag is set to YES then the generated HTML
+# documentation will contain a main index with vertical navigation menus that
+# are dynamically created via Javascript. If disabled, the navigation index will
+# consists of multiple levels of tabs that are statically embedded in every HTML
+# page. Disable this option to support browsers that do not have Javascript,
+# like the Qt help browser.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_DYNAMIC_MENUS     = YES
+
 # If the HTML_DYNAMIC_SECTIONS tag is set to YES then the generated HTML
 # documentation will contain sections that can be hidden and shown after the
 # page has loaded.
@@ -1245,12 +1291,12 @@ HTML_INDEX_NUM_ENTRIES = 100
 
 # If the GENERATE_DOCSET tag is set to YES, additional index files will be
 # generated that can be used as input for Apple's Xcode 3 integrated development
-# environment (see: http://developer.apple.com/tools/xcode/), introduced with
+# environment (see: https://developer.apple.com/tools/xcode/), introduced with
 # OSX 10.5 (Leopard). To create a documentation set, doxygen will generate a
 # Makefile in the HTML output directory. Running make will produce the docset in
 # that directory and running make install will install the docset in
 # ~/Library/Developer/Shared/Documentation/DocSets so that Xcode will find it at
-# startup. See http://developer.apple.com/tools/creatingdocsetswithdoxygen.html
+# startup. See https://developer.apple.com/tools/creatingdocsetswithdoxygen.html
 # for more information.
 # The default value is: NO.
 # This tag requires that the tag GENERATE_HTML is set to YES.
@@ -1366,7 +1412,7 @@ QCH_FILE               =
 
 # The QHP_NAMESPACE tag specifies the namespace to use when generating Qt Help
 # Project output. For more information please see Qt Help Project / Namespace
-# (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#namespace).
+# (see: http://doc.qt.io/qt-4.8/qthelpproject.html#namespace).
 # The default value is: org.doxygen.Project.
 # This tag requires that the tag GENERATE_QHP is set to YES.
 
@@ -1374,8 +1420,7 @@ QHP_NAMESPACE          = org.doxygen.Project
 
 # The QHP_VIRTUAL_FOLDER tag specifies the namespace to use when generating Qt
 # Help Project output. For more information please see Qt Help Project / Virtual
-# Folders (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#virtual-
+# Folders (see: http://doc.qt.io/qt-4.8/qthelpproject.html#virtual-folders).
-# folders).
 # The default value is: doc.
 # This tag requires that the tag GENERATE_QHP is set to YES.
 
@@ -1383,23 +1428,21 @@ QHP_VIRTUAL_FOLDER     = doc
 
 # If the QHP_CUST_FILTER_NAME tag is set, it specifies the name of a custom
 # filter to add. For more information please see Qt Help Project / Custom
-# Filters (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#custom-
+# Filters (see: http://doc.qt.io/qt-4.8/qthelpproject.html#custom-filters).
-# filters).
 # This tag requires that the tag GENERATE_QHP is set to YES.
 
 QHP_CUST_FILTER_NAME   = 
 
 # The QHP_CUST_FILTER_ATTRS tag specifies the list of the attributes of the
 # custom filter to add. For more information please see Qt Help Project / Custom
-# Filters (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#custom-
+# Filters (see: http://doc.qt.io/qt-4.8/qthelpproject.html#custom-filters).
-# filters).
 # This tag requires that the tag GENERATE_QHP is set to YES.
 
 QHP_CUST_FILTER_ATTRS  = 
 
 # The QHP_SECT_FILTER_ATTRS tag specifies the list of the attributes this
 # project's filter section matches. Qt Help Project / Filter Attributes (see:
-# http://qt-project.org/doc/qt-4.8/qthelpproject.html#filter-attributes).
+# http://doc.qt.io/qt-4.8/qthelpproject.html#filter-attributes).
 # This tag requires that the tag GENERATE_QHP is set to YES.
 
 QHP_SECT_FILTER_ATTRS  = 
@@ -1492,7 +1535,7 @@ EXT_LINKS_IN_WINDOW    = NO
 
 FORMULA_FONTSIZE       = 10
 
-# Use the FORMULA_TRANPARENT tag to determine whether or not the images
+# Use the FORMULA_TRANSPARENT tag to determine whether or not the images
 # generated for formulas are transparent PNGs. Transparent PNGs are not
 # supported properly for IE 6.0, but are supported on all modern browsers.
 #
@@ -1504,7 +1547,7 @@ FORMULA_FONTSIZE       = 10
 FORMULA_TRANSPARENT    = YES
 
 # Enable the USE_MATHJAX option to render LaTeX formulas using MathJax (see
-# http://www.mathjax.org) which uses client side Javascript for the rendering
+# https://www.mathjax.org) which uses client side Javascript for the rendering
 # instead of using pre-rendered bitmaps. Use this if you do not have LaTeX
 # installed or if you want to formulas look prettier in the HTML output. When
 # enabled you may also need to install MathJax separately and configure the path
@@ -1531,7 +1574,7 @@ MATHJAX_FORMAT         = HTML-CSS
 # MATHJAX_RELPATH should be ../mathjax. The default value points to the MathJax
 # Content Delivery Network so you can quickly see the result without installing
 # MathJax. However, it is strongly recommended to install a local copy of
-# MathJax from http://www.mathjax.org before deployment.
+# MathJax from https://www.mathjax.org before deployment.
 # The default value is: http://cdn.mathjax.org/mathjax/latest.
 # This tag requires that the tag USE_MATHJAX is set to YES.
 
@@ -1593,7 +1636,7 @@ SERVER_BASED_SEARCH    = NO
 #
 # Doxygen ships with an example indexer (doxyindexer) and search engine
 # (doxysearch.cgi) which are based on the open source search engine library
-# Xapian (see: http://xapian.org/).
+# Xapian (see: https://xapian.org/).
 #
 # See the section "External Indexing and Searching" for details.
 # The default value is: NO.
@@ -1606,7 +1649,7 @@ EXTERNAL_SEARCH        = NO
 #
 # Doxygen ships with an example indexer (doxyindexer) and search engine
 # (doxysearch.cgi) which are based on the open source search engine library
-# Xapian (see: http://xapian.org/). See the section "External Indexing and
+# Xapian (see: https://xapian.org/). See the section "External Indexing and
 # Searching" for details.
 # This tag requires that the tag SEARCHENGINE is set to YES.
 
@@ -1793,12 +1836,20 @@ LATEX_SOURCE_CODE      = NO
 
 # The LATEX_BIB_STYLE tag can be used to specify the style to use for the
 # bibliography, e.g. plainnat, or ieeetr. See
-# http://en.wikipedia.org/wiki/BibTeX and \cite for more info.
+# https://en.wikipedia.org/wiki/BibTeX and \cite for more info.
 # The default value is: plain.
 # This tag requires that the tag GENERATE_LATEX is set to YES.
 
 LATEX_BIB_STYLE        = plain
 
+# If the LATEX_TIMESTAMP tag is set to YES then the footer of each generated
+# page will contain the date and time when the page was generated. Setting this
+# to NO can help when comparing the output of multiple runs.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_TIMESTAMP        = NO
+
 #---------------------------------------------------------------------------
 # Configuration options related to the RTF output
 #---------------------------------------------------------------------------
@@ -1968,9 +2019,9 @@ DOCBOOK_PROGRAMLISTING = NO
 #---------------------------------------------------------------------------
 
 # If the GENERATE_AUTOGEN_DEF tag is set to YES, doxygen will generate an
-# AutoGen Definitions (see http://autogen.sf.net) file that captures the
+# AutoGen Definitions (see http://autogen.sourceforge.net/) file that captures
-# structure of the code including all documentation. Note that this feature is
+# the structure of the code including all documentation. Note that this feature
-# still experimental and incomplete at the moment.
+# is still experimental and incomplete at the moment.
 # The default value is: NO.
 
 GENERATE_AUTOGEN_DEF   = NO
@@ -2392,6 +2443,11 @@ DIAFILE_DIRS           =
 
 PLANTUML_JAR_PATH      = 
 
+# When using plantuml, the PLANTUML_CFG_FILE tag can be used to specify a
+# configuration file for plantuml.
+
+PLANTUML_CFG_FILE      = 
+
 # When using plantuml, the specified paths are searched for files specified by
 # the !include statement in a plantuml block.
 

doc/Index.md

@@ -1,41 +0,0 @@
-![](https://raw.githubusercontent.com/Naios/continuable/master/doc/slideshow.gif)
-
-## Content
-
-- **Class cti::continuable_base** - for building up a continuation chain.
-  - \link cti::continuable_base::then then\endlink - adds a callback or cti::continuable_base to the invocation chain.
-  - \link cti::continuable_base::fail fail\endlink - adds an error callback to the invocation chain.
-  - \link cti::continuable_base::next next\endlink - adds an error and result callback to the invocation chain.
-  - \link cti::continuable_base::operator | operator|\endlink - connects another object through \link cti::continuable_base::then then\endlink.
-  - \link cti::continuable_base::operator && operator&&\endlink - connects another cti::continuable_base with an *all* logic.
-  - \link cti::continuable_base::operator|| operator||\endlink - connects another cti::continuable_base with an *any* logic.
-  - \link cti::continuable_base::operator>> operator>>\endlink - connects another cti::continuable_base with a *sequential* logic.
-  - \link cti::continuable_base::done done\endlink - \copybrief cti::continuable_base::done
-  - \link cti::continuable_base::freeze freeze \endlink - prevents the automatic invocation on destruction of the cti::continuable_base.
-  - \link cti::continuable_base::is_frozen is_frozen\endlink - \copybrief cti::continuable_base::is_frozen
-- **Class cti::promise_base** - for resolving a continuation chain through a result or error.
-  - \link cti::promise_base::set_value set_value\endlink - resolves the continuation chain through a result.
-  - \link cti::promise_base::set_exception set_exception\endlink - resolves the continuation chain through an error.
-- **Helper functions**
-  - \link cti::make_continuable make_continuable\endlink - creates a cti::continuable_base from a callback tanking function.
-  - \link cti::when_all when_all\endlink - connects all given cti::continuable_base objects with an *all* logic.
-  - \link cti::when_any when_any\endlink - connects all given cti::continuable_base objects with an *any* logic.
-  - \link cti::when_seq when_seq\endlink - connects all given cti::continuable_base objects with a *sequence* logic.
-- **Transforms** - Apply a transform to the continuable
-  - \link cti::transforms::futurize futurize\endlink - \copybrief cti::transforms::futurize
-  - \link cti::transforms::flatten flatten\endlink - \copybrief cti::transforms::flatten
-- **Predefined (erased) types** - Predefined type erarasures for continuables and promises
-  - \link cti::promise promise\endlink - \copybrief cti::promise
-  - \link cti::continuable continuable\endlink - \copybrief cti::continuable
-  - \link cti::unique_continuable unique_continuable\endlink - \copybrief cti::unique_continuable
-- **Class cti::continuable_trait** - A trait class for defining your own cti::continuable_base trait with the type-erasure backend of your choice.
-  - \link cti::continuable_trait::promise promise\endlink - \copybrief cti::continuable_trait::promise
-  - \link cti::continuable_trait::continuable continuable\endlink - \copybrief cti::continuable_trait::continuable
-- **GTest macros:**
-  - \link ASSERT_ASYNC_COMPLETION ASSERT_ASYNC_COMPLETION \endlink - \copybrief ASSERT_ASYNC_COMPLETION
-  - \link ASSERT_ASYNC_INCOMPLETION ASSERT_ASYNC_INCOMPLETION \endlink - \copybrief ASSERT_ASYNC_INCOMPLETION
-  - \link ASSERT_ASYNC_VALIDATION ASSERT_ASYNC_VALIDATION \endlink - \copybrief ASSERT_ASYNC_VALIDATION
-  - \link ASSERT_ASYNC_BINARY_VALIDATION ASSERT_ASYNC_BINARY_VALIDATION \endlink - \copybrief ASSERT_ASYNC_BINARY_VALIDATION
-  - \link EXPECT_ASYNC_RESULT EXPECT_ASYNC_RESULT \endlink - \copybrief EXPECT_ASYNC_RESULT
-  - \link ASSERT_ASYNC_RESULT ASSERT_ASYNC_RESULT \endlink - \copybrief ASSERT_ASYNC_RESULT
-  - \link ASSERT_ASYNC_TYPES ASSERT_ASYNC_TYPES \endlink - \copybrief ASSERT_ASYNC_TYPES

doc/changelog.dox

@@ -0,0 +1,303 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page changelog Changelog
+\brief A description of the changes made to continuable.
+
+\section changelog-versions Versions
+
+Following versions were released:
+
+\subsection changelog-versions-4-0-0 4.0.0
+
+Various issues have been resolved:
+
+- [#27: First class, zero-overhead ASIO integration](https://github.com/Naios/continuable/issues/27)
+- [#23: VS 16.2: parameter pack must be expanded in this context](https://github.com/Naios/continuable/issues/23)
+- [#21: Infinite recursion during compilation](https://github.com/Naios/continuable/issues/21)
+- [#16: Add AppleClang compiler to cmake](https://github.com/Naios/continuable/issues/16)
+- [#13: unit-test/test-continuable-single fails on gcc 8.2](https://github.com/Naios/continuable/issues/13)
+- [#11: Forward declarations are no longer allowed in type-erased continuables](https://github.com/Naios/continuable/issues/11)
+
+Following methods and functions have been added:
+
+<B>Various improvements to continuable_base:</B>
+
+- \ref continuable_base::as for casting to a continuable_base with different arguments
+- \ref continuable_base::finish for 'materializing' an intermediate chained continuable_base
+
+<B>An asychronous initiation function comparable to std::async:</B>
+
+The asynchronous facilities make it possible now to start with a handler
+instead of a continuation:
+
+\code{.cpp}
+async([] {
+  // ...
+}).then(...);
+\endcode
+
+- \ref async Makes it possible to start with a handler instead of a continuation, comparable to `std::async`
+- \ref async_on allows to specify an additional executor parameter
+
+<B>The result class and modifying the asynchronous control flow</B>
+
+Every continuation handler used in \ref continuable_base::then, \ref continuable_base::next
+and \ref continuable_base::fail allows now to return a \ref result which represents
+the asynchronous result.
+
+This allows recovering from failures or throwing of exception types from
+handlers when exceptions are disabled.
+
+Result handling and
+- \ref result
+- \ref rethrow Throws an exception or error code from a result or failure handler
+- \ref cancel Throws a default constructed exception type or error code from a result or failure handler to signal cancellation.
+- \ref stop \copybrief stop
+- \ref make_result \copybrief make_result
+
+Special result types
+- \ref empty_result \copybrief empty_result
+- \ref cancellation_result \copybrief cancellation_result
+- \ref exceptional_result \copybrief exceptional_result
+
+<B>Optimize 'ready' continuables:</B>
+
+Continuables which are 'ready' and side effect free can now be unpacked
+synchronously. Mainly such continuables are created through \ref make_ready_continuable,
+\ref make_exceptional_continuable and \ref make_cancelling_continuable.
+
+- \ref continuable_base::is_ready \copybrief continuable_base::is_ready
+- \ref continuable_base::unpack \copybrief continuable_base::unpack
+- \ref make_cancelling_continuable \copybrief make_cancelling_continuable
+
+Including various helper tags for the underlying changed continuation object structure:
+
+- \ref signature_arg_t
+- \ref is_ready_arg_t
+- \ref unpack_arg_t
+- \ref exception_arg_t
+- \ref exception_t
+
+<B>asio asynchronous initiate token:</B>
+
+The \ref use_continuable_t special tag can be used to make (boost) asio
+return a \ref continuable_base.
+
+- \ref use_continuable \copybrief use_continuable_t
+
+\code{.cpp}
+#include <continuable/continuable.hpp>
+#include <continuable/external/asio.hpp>
+#include <asio.hpp>
+
+// ...
+
+asio::tcp::resolver resolver(...);
+resolver.async_resolve("127.0.0.1", "daytime", cti::use_continuable)
+  .then([](asio::udp::resolver::iterator iterator) {
+    // ...
+  });
+\endcode
+
+<B>Iterating over an asynchronous control flow:</B>
+
+The loop function was added which makes is possible to emulate an asynchronous loop,
+that is comparable to a `co_await` with `for`.
+
+- \ref loop \copybrief loop
+- \ref loop_result \copybrief loop_result
+- \ref loop_break \copybrief loop_break
+- \ref loop_continue \copybrief loop_continue
+- \ref range_loop \copybrief range_loop
+- \ref range_loop \copybrief range_loop
+- \ref plain_t \copybrief plain_t
+- \ref make_plain \copybrief make_plain
+
+<B>Synchronous wait transforms:</B>
+
+The wait transforms allows to block the current thread until a \ref continuable_base
+was resolved.
+
+- \ref transforms::wait \copybrief transforms::wait
+- \ref transforms::wait_for Same as \ref transforms::wait wich waits for a given duration
+- \ref transforms::wait_until Same as \ref transforms::wait wich waits until a given timepoint
+
+<B>Various changes:</B>
+
+Many more unlisted changes including:
+
+- \ref work \copybrief work
+- \ref continuation_capacity
+- \ref promisify::with \copybrief promisify::with
+- \ref void_arg_t
+
+Additional various bugfixes have been made.
+
+\subsection changelog-versions-3-0-0 3.0.0
+
+<B>New helper functions</B>
+
+New helper functions were added to create ready continuables:
+
+- \ref make_ready_continuable \copybrief make_ready_continuable
+- \ref make_exceptional_continuable \copybrief make_exceptional_continuable
+
+<B>Improvements to connections</B>
+
+The implementation of connections were rewritten entirely.
+It is possible now to connect runtime sized containers as well as
+deeply nested sequences. See \ref tutorial-connecting-continuables for details.
+
+Additionally connection overloads were added that accept two iterators
+in order to come closer to the interface of the standard library.
+
+Also \ref populate was added which makes it possible to populate
+a dynamic container from \ref continuable_base objects.
+
+<B>Disabled copies for promises and continuables entirely</B>
+
+The \ref promise_base and \ref continuable_base is now non copyable.
+This change should make it easier to work with the move only
+semantic of continuables in order to make less mistakes.
+
+<B>Traversal API</B>
+
+A new traversal API for synchronous and asynchronous pack traversal
+was added which makes it easy to specify new connection types.
+
+\subsection changelog-versions-2-0-0 2.0.0
+
+<B>Error handling</B>
+
+Usually it is inconvenient to handle error codes and exceptions in an
+asynchronous context, as we all know `std::future` supports error handling
+through exceptions already. We now introduce this capability to the
+continuable library while allowing error codes to be used as well.
+
+Consider the function `cti::continuable<> get_bad_continuable()`
+which always resolves through an error, then you may handle the error code
+or exception as following:
+
+\code{.cpp}
+get_bad_continuable()
+  .then([] {
+    // ... never invoked
+  })
+  .then([] {
+    // ... never invoked as well
+  })
+  .fail([] (std::exception_ptr e) {
+    try {
+      std::rethrow_exception(e);
+    } catch(std::exception const& e) {
+      // Handle the exception here
+    }
+  });
+\endcode
+
+
+<B>Abstracting callbacks as promises</B>
+
+Since a callback may be called through an error or result the cri::promise
+class was added in order ro provide a similar interface to std::promise:
+
+
+\code{.cpp}
+auto http_request(std::string url) {
+  return cti::make_continuable<std::string>(
+    [url = std::move(url)](cti::promise<std::string> promise) {
+      // Perform the actual request through a different library,
+      // resolve the promise upon completion of the task.
+      promise.set_value("<html> ... </html>");
+      // ...or promise.set_exception(...);
+    });
+}
+\endcode
+
+<B>`co_await` support</B>
+
+Experimental coroutine (`co_await` and `co_return`) support was added,
+this is available on MSVC 2017 and Clang 5.0.
+
+\code{.cpp}
+int i = co_await cti::make_continuable<int>([](auto&& promise) {
+  promise.set_value(0);
+});
+\endcode
+
+<B>Minor improvements</B>
+
+The library was improved in other ways:
+
+- `constexpr` and `noexcept` improvements
+- Compile-time improvements
+- Documentation improvements
+
+<B>Header split</B>
+
+Since the overall library size was increased the headers were split into smaller chunks.
+
+\subsection changelog-versions-1-0-0 1.0.0
+
+- Documentation and readme changes
+- Change the assertion type of some GTest macros from expected to assertion.
+
+\subsection changelog-versions-0-8-0 0.8.0 (unstable)
+
+- Fixes a major issue with handling the ownership for consumed continuables
+  which led to unintended invocations.
+- Adds partial application support which makes it possible to chain callbacks
+  which accept less arguments then the curret signature.
+  \code{.cpp}
+  http_request("github.com")
+    .then([] {
+      // ...
+    });
+  \endcode
+- Adds Support for sequential invocation:
+  \code{.cpp}
+  http_request("github.com") >> http_request("atom.io")
+    .then([] (std::string github, std::string atom) {
+      // ...
+    });
+  \endcode
+
+\subsection changelog-versions-0-7-0 0.7.0 (unstable)
+
+- Continuation syntactic sugar
+- Executor support
+- Connection support
+
+\section changelog-semver Semantic versioning and stability
+
+Continuable strictly follows the rules of
+[semantic versioning](http://semver.org/), the API is kept stable
+across minor versions.
+
+The CI driven unit-tests are observed through the Clang sanitizers
+(asan, ubsan and lsan - when compiling with Clang) or
+Valgrind (when compiling with GCC) in order to prevent regressions.
+
+*/
+}

doc/code/CMakeLists.txt

@@ -1,2 +0,0 @@
-add_subdirectory(documentation)
-add_subdirectory(slideshow)

doc/code/documentation/CMakeLists.txt

@@ -1,5 +0,0 @@
-add_executable(doc-documentation
-  ${CMAKE_CURRENT_LIST_DIR}/doc-documentation.cpp)
-target_link_libraries(doc-documentation
-  PRIVATE
-    continuable)

doc/code/documentation/doc-documentation.cpp

@@ -1,152 +0,0 @@
-/*
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#include <string>
-
-#include <continuable/continuable.hpp>
-#include <continuable/detail/util.hpp>
-
-using cti::detail::util::unused;
-
-void creating_continuables() {
-  auto void_continuable = cti::make_continuable<void>([](auto&& callback) {
-    //                                          ^^^^
-
-    // Call the promise later when you have finished your work
-    callback.set_value();
-  });
-
-  auto str_continuable =
-      cti::make_continuable<std::string>([](auto&& callback) {
-        //                                         ^^^^^^^^^^^
-        callback.set_value("Hello, World!");
-      });
-}
-
-struct ResultSet {};
-template <typename... Args>
-void mysql_handle_async_query(Args&&...) {
-}
-
-auto mysql_query(std::string query) {
-  return cti::make_continuable<ResultSet>([query = std::move(query)](
-      auto&& callback) mutable {
-    // Pass the callback to the handler which calls the callback when finished.
-    // Every function accepting callbacks works with continuables.
-    mysql_handle_async_query(std::move(query),
-                             std::forward<decltype(callback)>(callback));
-  });
-}
-
-void providing_helper_functions() {
-  // You may use the helper function like you would normally do,
-  // without using the support methods of the continuable.
-  mysql_query("DELETE FROM `users` WHERE `id` = 27361");
-
-  // Or using chaining to handle the result which is covered in the
-  // documentation.
-  mysql_query("SELECT `id`, `name` FROM users").then([](ResultSet result) {
-    // ...
-    unused(result);
-  });
-}
-
-void chaining_continuables() {
-  mysql_query("SELECT `id`, `name` FROM `users`")
-      .then([](ResultSet users) {
-        (void)users;
-        // Return the next continuable to process ...
-        return mysql_query("SELECT `id` name FROM `sessions`");
-      })
-      .then([](ResultSet sessions) {
-        // ... or pass multiple values to the next callback using tuples or
-        // pairs ...
-        return std::make_tuple(std::move(sessions), true);
-      })
-      .then([](ResultSet sessions, bool is_ok) {
-        (void)sessions;
-        (void)is_ok;
-        // ... or pass a single value to the next callback ...
-        return 10;
-      })
-      .then([](auto value) {
-        //     ^^^^ Templated callbacks are possible too
-        (void)value;
-      })
-      // ... you may even pass continuables to the `then` method directly:
-      .then(mysql_query("SELECT * `statistics`"))
-      .then([](ResultSet result) {
-        // ...
-        (void)result;
-      });
-}
-
-auto http_request(std::string /*url*/) {
-  return cti::make_continuable<std::string>([](auto&& callback) {
-    // ...
-    callback.set_value("<html>...</html>");
-  });
-}
-
-void connecting_continuables() {
-  // `all` of connections:
-  (http_request("github.com") && http_request("travis-ci.org") &&
-   http_request("atom.io"))
-      .then([](std::string github, std::string travis, std::string atom) {
-        // The callback is called with the response of github, travis and atom.
-        unused(github, travis, atom);
-      });
-
-  // `any` of connections:
-  (http_request("github.com") || http_request("travis-ci.org") ||
-   http_request("atom.io"))
-      .then([](std::string github_or_travis_or_atom) {
-        // The callback is called with the first response of either github,
-        // travis or atom.
-        unused(github_or_travis_or_atom);
-      });
-
-  // mixed logical connections:
-  (http_request("github.com") &&
-   (http_request("travis-ci.org") || http_request("atom.io")))
-      .then([](std::string github, std::string travis_or_atom) {
-        // The callback is called with the response of github for sure
-        // and the second parameter represents the response of travis or atom.
-        unused(github, travis_or_atom);
-      });
-
-  // There are helper functions for connecting continuables:
-  auto all =
-      cti::when_all(http_request("github.com"), http_request("travis-ci.org"));
-  auto any =
-      cti::when_any(http_request("github.com"), http_request("travis-ci.org"));
-}
-
-int main() {
-  creating_continuables();
-
-  providing_helper_functions();
-
-  chaining_continuables();
-
-  connecting_continuables();
-}

doc/code/slideshow/CMakeLists.txt

@@ -1,5 +0,0 @@
-add_executable(doc-slideshow
-  ${CMAKE_CURRENT_LIST_DIR}/doc-slideshow.cpp)
-target_link_libraries(doc-slideshow
-  PRIVATE
-    continuable)

doc/configuration.dox

@@ -0,0 +1,41 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page configuration Configuration
+\brief Covers optional preprocessor macros that change the libraries behaviour
+
+By default the library doesn't require any preprocessor definitions
+to be defined in order to work. However it is possible to define some
+in order to change the libraries behaviour:
+
+| Preprocessor definition                   | Consequence     |
+| ----------------------------------------- | --------------- |
+| `CONTINUABLE_WITH_NO_EXCEPTIONS`          | Exceptions are disabled and `std::error_condition` is used as \ref error_type . See \ref tutorial-chaining-continuables-fail for details. |
+| `CONTINUABLE_WITH_CUSTOM_ERROR_TYPE`      | Exceptions are disabled and the type defined by `CONTINUABLE_WITH_CUSTOM_ERROR_TYPE` is used as \ref error_type . See \ref tutorial-chaining-continuables-fail for details. |
+| `CONTINUABLE_WITH_UNHANDLED_EXCEPTIONS`   | Allows unhandled exceptions in asynchronous call hierarchies. See \ref tutorial-chaining-continuables-fail for details. |
+| `CONTINUABLE_WITH_CUSTOM_FINAL_CALLBACK`  | Allows to customize the final callback which can be used to implement custom unhandled asynchronous exception handlers. |
+| `CONTINUABLE_WITH_IMMEDIATE_TYPES`        | Don't decorate the used type erasure, which is done to keep type names minimal for better error messages in debug builds. |
+| `CONTINUABLE_WITH_EXPERIMENTAL_COROUTINE` | Enables support for experimental coroutines and `co_await` expressions. See \ref continuable_base::operator co_await() for details. |
+
+*/
+}

doc/doxygen/.gitignore

@@ -1 +0,0 @@
-doxygen/

doc/index.dox

@@ -0,0 +1,101 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \mainpage Continuable
+
+\section mainpage-overview Overview
+
+<b>Continuable is a C++14 library that provides full support for:</b>
+ - lazy async continuation chaining based on **callbacks**
+   (\link continuable_base::then then\endlink) and
+   expression templates, callbacks are wrapped nicely as \link promise_base promises\endlink.
+ - **no enforced type-erasure** which means we need <b>less heap
+   allocations</b> than comparable libraries, strictly following the <b>"don't
+   pay for what you don't use"</b> principle.
+ - support for **all, any and sequential connections** between continuables
+   through expressive operator overloads \link continuable_base::operator && &&\endlink,
+   \link continuable_base::operator || ||\endlink and
+   \link continuable_base::operator>> >>\endlink as well as free functions
+   \ref when_all, \ref when_any and \ref when_seq.
+ - asynchronous \link continuable_base::fail error handling\endlink through
+   \link promise_base::set_exception exceptions\endlink,
+   \link configuration error codes\endlink and
+   \link configuration user defined types\endlink.
+ - **syntactic sugar** for instance: **partial invocation**, **tuple unpacking**,
+   `co_await` support and \link continuable_base::then executors\endlink.
+ - **encapsuled from any runtime**, larger framework or executors makes
+   it possible to use continuable even in smaller or esoteric  usage scenarios.
+
+\section mainpage-getting-started Getting started
+
+Continuable is a header-only library with zero compilation dependencies.
+The \ref installation and \ref configuration are explained in its own chapter.
+
+The \ref tutorial is everything you need in order to get to know the libraries
+API. Beside of this, there is a detailed in-source documentation provided.
+
+Continuable follows the semantic versioning schema and changes are listed
+in the \ref changelog.
+
+\section mainpage-contact Contributing and Questions
+
+Through the [Github issue tracker](https://github.com/Naios/continuable/issues)
+you are welcomed to ask for questions, contribute code or request new features.
+Also I would like to hear your personal opinion about the library design or
+your personal experience in using the library to improve it.
+
+\attention If you like the library I would be glad if you star it on Github,
+           because it helps other users to find this library.
+
+\note If you are using the library in your open-source or commercial project
+      I would highly appreciate if you could give me a short notice so I can
+      add you to a list of projects and companies using this library.
+
+\section mainpage-license License
+
+Continuable is licensed under the MIT license:
+
+>
+>   Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+>
+>   Permission is hereby granted, free of charge, to any person obtaining a copy
+>   of this software and associated documentation files(the "Software"), to deal
+>   in the Software without restriction, including without limitation the rights
+>   to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+>   copies of the Software, and to permit persons to whom the Software is
+>   furnished to do so, subject to the following conditions :
+>
+>   The above copyright notice and this permission notice shall be included in
+>   all copies or substantial portions of the Software.
+>
+>   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+>   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+>   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+>   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+>   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+>   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+>   SOFTWARE.
+>
+
+*/
+}

doc/installation.dox

@@ -0,0 +1,157 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page installation Installation
+\brief An explanation on how to install continuable on various platforms.
+
+\tableofcontents
+
+\section installation-requirements Requirements
+
+Continuable requires a fairly new toolchain and was verified to work with
+following compilers:
+
+- Visual Studio 2017+ Update 2
+- Clang 5.0+
+- GCC 6.0+
+
+Although the build is observed with the listed compilers earlier
+versions might work.
+
+\warning GCC is proven to be slower than Clang in template compilation and
+         thus it is suggested to use Clang instead.
+
+\section installation-dependencies Dependencies
+
+Continuable is a header-only library with one required header-only dependency:
+
+  - [Naios/function2](https://github.com/Naios/function2) is used as type
+    erasure wrapper to convert a \ref continuable_base into a \ref continuable.
+
+Additionally GTest is required as optional dependency for the asynchronous
+unit testing macros defined in `continuable/support/gtest.hpp`
+if those are used:
+
+  - [google/googletest](https://github.com/google/googletest) is used as
+    unit testing framework and to provide asynchronous testing macros.
+
+For the examples and unit tests there might be more dependencies used,
+which are fetched through git submodules.
+
+\note The library only depends on the standard library when following
+      headers are used:
+- `continuable/continuable-base.hpp`
+- `continuable/continuable-promise-base.hpp`
+- `continuable/continuable-connections.hpp`
+- `continuable/continuable-promisify.hpp`
+- `continuable/continuable-transforms.hpp`
+
+\section installation-installation Installation
+
+Making continuable available inside your project is possible through
+various ways.
+
+\subsection installation-installation-cmake Through CMake
+
+The continuable build is driven by CMake and the project exposes CMake
+interface targets when being used by external projects:
+
+\code{.cmake}
+add_subdirectory(continuable)
+# continuable provides an interface target which makes it's
+# headers available to all projects using the continuable library.
+target_link_libraries(my_project continuable)
+\endcode
+
+When adding the continuable subdirectory as git submodule this should work
+out of the box.
+
+\code{.sh}
+git submodule add https://github.com/Naios/continuable.git
+\endcode
+
+\attention On POSIX platforms you are required to link your application against
+           a corresponding thread library, otherwise `std::futures` won't work
+           properly, this is done automatically by the provided CMake project.
+
+Additionally the CMake project exports a `continuable` target which is
+importable through the \code{.cmake}find_package\endcode CMake command
+when installed:
+
+\code{.sh}
+mkdir build
+cd build
+cmake ..
+cmake --build . --target INSTALL --config Release
+\endcode
+
+In your `CMakeLists.txt`:
+
+\code{.cmake}
+find_package(continuable REQUIRED)
+\endcode
+
+\subsection installation-installation-pkg Through package managers
+
+Continuable is present in some package managers and registries already,
+and might be installed from there.
+
+\attention The project is still looking for contributions that would help
+           to make it available from various package managers in order to
+           make the installation easier.
+
+\subsection installation-installation-amalgamation By using the amalgamation header
+
+For major versions there is an amalgamation header provided which can be
+included without any dependency:
+
+- [4.0.0](https://gist.githubusercontent.com/Naios/25d731aa4707d35a9bcec507f3cb9038/raw/051d2ea07b6704893c7fc9844e8d1c105c6821e0/continuable.hpp)
+- [3.0.0](https://gist.githubusercontent.com/Naios/b128ab5028a7eb33e4285c0293573d9f/raw/79fe332964a786b21a8661ef65d07a5669260a3c/continuable.hpp)
+
+\subsection installation-installation-copy By copying the headers
+
+If you don't want to rely on CMake or package managers it is possible to
+copy and include the `include` directories of continuable and
+[Naios/function2](https://github.com/Naios/function2) into your project.
+
+As an improvement git submodules could be used:
+
+\code{.sh}
+git submodule add https://github.com/Naios/continuable.git
+git submodule add https://github.com/Naios/function2.git
+\endcode
+
+\section installation-unit-tests Building the unit tests
+
+In order to build the unit tests clone the repository recursively
+with all submodules:
+
+\code{.sh}
+# Shell:
+git clone --recursive https://github.com/Naios/continuable.git
+\endcode
+
+Then CMake can be used to generate a project solution for testing.
+
+*/
+}

doc/tutorial-awaiting-continuables.dox

@@ -0,0 +1,129 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page tutorial-awaiting-continuables Awaiting continuables
+\brief Explains how to use the \ref continuable_base together with `co_await`.
+
+\tableofcontents
+
+\section tutorial-awaiting-continuables-usage Using co_await on continuables
+
+Coroutines (`co_await`) are supported by continuables when the underlying
+toolchain supports the TS. Currently this works in MSVC 2017 and Clang 5.0.
+
+\attention You have to enable this feature through defining the
+           `CONTINUABLE_WITH_EXPERIMENTAL_COROUTINE` preprocessor definition.
+
+It is possible to await for any \ref continuable_base as shown below:
+
+\code{.cpp}
+int i = co_await cti::make_continuable<int>([](auto&& promise) {
+  promise.set_value(0);
+});
+\endcode
+
+As described in \ref continuable_base::operator co_await() a continuable with
+multiple arguments as result will wrap its result into a `std::tuple`:
+
+\code{.cpp}
+std::tuple<int, int> i = co_await cti::make_ready_continuable(0, 1);
+\endcode
+
+\section tutorial-awaiting-continuables-await Using co_await with exceptions
+
+When a \ref continuable_base was resolved through an exception the exception
+is rethrown from the `co_await` expression:
+
+\code{.cpp}
+try {
+  auto response = co_await http_request("github.com");
+} catch(std::exception const& e) {
+  // Handle the exception
+}
+\endcode
+
+\section tutorial-awaiting-continuables-noexcept Using co_await with disabled exceptions
+
+In case the library is configured to use error codes or a custom
+error type the return type of the co_await expression is changed.
+
+The result is returned through an internal proxy object which may
+be queried for the error object:
+
+|          Continuation type        |          co_await returns          |
+| : ------------------------------- | : -------------------------------- |
+| `continuable_base with <>`        | `unspecified<void>`                |
+| `continuable_base with <Arg>`     | `unspecified<Arg>`                 |
+| `continuable_base with <Args...>` | `unspecified<std::tuple<Args...>>` |
+
+The interface of the proxy object is similar to the one proposed in
+the `std::expected` proposal:
+
+\code{.cpp}
+if (auto&& result = co_await http_request("github.com")) {
+  auto value = *result;
+} else {
+  cti::error_type error = result.get_exception();
+}
+
+auto result = co_await http_request("github.com");
+
+bool(result);
+result.is_value();
+result.is_exception();
+*result; // Same as result.get_value()
+result.get_value();
+result.get_exception();
+\endcode
+
+\section tutorial-awaiting-continuables-return Using continuables as return type from coroutines
+
+It is possible to use a \ref continuable_base as return type from coroutines.
+
+\code{.cpp}
+cti::continuable<> resolve_async_void() {
+  co_await http_request("github.com");
+  // ...
+  co_return;
+}
+
+cti::continuable<int> resolve_async() {
+  co_await http_request("github.com");
+  // ...
+  co_return 0;
+}
+\endcode
+
+Additionally it's possible to return multiple return values from coroutines
+by wrapping those in a tuple like type:
+
+\code{.cpp}
+cti::continuable<int, int, int> resolve_async_multiple() {
+  co_await http_request("github.com");
+  // ...
+  co_return std::make_tuple(0, 1, 2);
+}
+\endcode
+
+*/
+}

doc/tutorial-chaining-continuables.dox

@@ -0,0 +1,215 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page tutorial-chaining-continuables Chaining continuables
+\brief Explains how to chain multiple \ref continuable_base objects together.
+
+\tableofcontents
+
+\section tutorial-chaining-continuables-then Using then and results
+
+A \ref continuable_base provides various methods to continue the asynchronous
+call hierarchy. The most important method therefor is
+\ref continuable_base::then which changes the object through attaching a
+result handler:
+
+\code{.cpp}
+http_request("github.com")
+  .then([] (std::string result) {
+    // Do something...
+  });
+\endcode
+
+A new \ref continuable_base is created which result depends on the return type
+of the handler. For instance it is possible to return plain values or the next
+\ref continuable_base to continue the call hierarchy.
+See \ref continuable_base::then for details.
+
+\code{.cpp}
+mysql_query("SELECT `id`, `name` FROM `users`")
+  .then([](ResultSet users) {
+    // Return the next continuable to process ...
+    return mysql_query("SELECT `id` name FROM `sessions`");
+  })
+  .then([](ResultSet sessions) {
+    // ... or pass multiple values to the next callback using tuples or pairs ...
+    return std::make_tuple(std::move(sessions), true);
+  })
+  .then([](ResultSet sessions, bool is_ok) {
+    // ... or pass a single value to the next callback ...
+    return 10;
+  })
+  .then([](auto value) {
+    //     ^^^^ Templated callbacks are possible too
+  })
+  // ... you may even pass continuables to the `then` method directly:
+  .then(mysql_query("SELECT * FROM `statistics`"))
+  .then([](ResultSet result) {
+    // ...
+  });
+\endcode
+
+\subsection tutorial-chaining-continuables-then-partial Making use of partial argument application
+
+Callbacks passed to \link continuable_base::then then \endlink are only called
+with the amount of arguments that are accepted.
+
+\code{.cpp}
+(http_request("github.com") && read_file("entries.csv"))
+  .then([] {
+    // ^^^^^^ The original signature was <std::string, Buffer>,
+    // however, the callback is only invoked with the amount of
+    // arguments it's accepting.
+  });
+\endcode
+
+This makes it possible to attach a callback accepting nothing to every
+\ref continuable_base.
+
+\subsection tutorial-chaining-continuables-then-executors Assigning a specific executor to then
+
+Dispatching a callback through a specific executor is a common usage scenario and supported through the second argument of \link continuable_base::then then\endlink:
+
+\code{.cpp}
+auto executor = [](auto&& work) {
+  // Dispatch the work here, store it for later
+  // invocation or move it to another thread.
+  std::forward<decltype(work)>(work)();
+};
+
+read_file("entries.csv")
+  .then([](Buffer buffer) {
+    // ...
+  }, executor);
+//   ^^^^^^^^
+\endcode
+
+The supplied `work` callable may be stored and moved for later usage
+on a possible different thread or execution context.
+
+\note If you are intending to change the context the asynchronous task is
+      running, you need to specify this inside the function that
+      supplies the \ref continuable_base through moving the \ref promise_base.
+\code{.cpp}
+auto http_request(std::string url) {
+  return cti::make_continuable<std::string>(
+    [url = std::move(url)](auto&& promise) {
+      std::async([promise = std::forward<decltype(promise)>(promise)]
+                  () mutable {
+                    promise.set_value("<html> ... </html>");
+                  });
+    });
+}
+\endcode
+
+\section tutorial-chaining-continuables-fail Using fail and exceptions
+
+Asynchronous exceptions are supported too. Exceptions that were set through
+\ref promise_base::set_exception are forwarded to the first available registered
+handler that was attached through \ref continuable_base::fail :
+
+\code{.cpp}
+http_request("github.com")
+  .then([] (std::string result) {
+    // Is never called if an error occurs
+  })
+  .fail([] (std::exception_ptr ptr) {
+    try {
+      std::rethrow_exception(ptr);
+    } catch(std::exception const& e) {
+      // Handle the exception or error code here
+    }
+  });
+\endcode
+
+Multiple handlers are allowed to be registered, however the asynchronous call
+hierarchy is aborted after the first called fail handler and only the closest
+handler below is called.
+
+\note Retrieving a `std::exception_ptr` from a current exception
+      may be done as shown below:
+  \code{.cpp}
+  auto do_sth() {
+    return cti::make_continuable<void>([=] (auto&& promise) {
+      try {
+        // Usually the exception is thrown by another expression
+        throw std::exception{};
+      } catch(...) {
+        promise.set_exception(std::current_exception());
+      }
+    });
+  }
+  \endcode
+
+Continuable also supports error codes automatically if exceptions are disabled.
+Additionally it is possible to specify a custom error type through defining.
+
+\code{.cpp}
+http_request("github.com")
+  .then([] (std::string result) {
+    // Is never called if an error occurs
+  })
+  .fail([] (std::error_condition error) {
+    error.value();
+    error.category();
+  });
+\endcode
+
+The \ref error_type will be `std::exception_ptr` except if any of the
+following definitions is defined:
+- `CONTINUABLE_WITH_NO_EXCEPTIONS`: Define this to use `std::error_condition`
+  as \ref error_type and to disable exception support.
+  When exceptions are disabled this definition is set automatically.
+- `CONTINUABLE_WITH_CUSTOM_ERROR_TYPE`:  Define this to use a user defined
+  error type.
+
+\attention By default unhandled exceptions or errors will trigger
+           a built-in trap that causes abnormal application shutdown.
+           In order to prevent this and to allow unhandled errors
+           define `CONTINUABLE_WITH_UNHANDLED_EXCEPTIONS`.
+
+\section tutorial-chaining-continuables-next Using next to handle all paths
+
+Sometimes it's required to provide a continuation and error handler from the
+same object. In order to avoid overloading conflicts there is the special
+method \ref continuable_base::next provided.
+The exception path overload is marked through the \ref dispatch_error_tag :
+
+\code{.cpp}
+struct handle_all_paths {
+  void operator() (std::string result) {
+    // ...
+  }
+  void operator() (cti::dispatch_error_tag, cti::error_type) {
+    // ...
+  }
+};
+
+// ...
+
+http_request("github.com")
+  .next(handle_all_paths{});
+\endcode
+
+*/
+}

doc/tutorial-connecting-continuables.dox

@@ -0,0 +1,212 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page tutorial-connecting-continuables Connecting continuables
+\brief Explains how to connect various \ref continuable_base objects together
+
+\tableofcontents
+
+\section tutorial-connecting-continuables-strategies Connections and strategies
+
+Connections make it possible to describe the dependencies between an arbitrary
+count of \ref continuable_base objects in order resolve a returned
+\ref continuable_base as soon as the dependencies are fulfilled.
+
+For each connection strategy \ref continuable_base provides an operator for
+for instance \ref continuable_base::operator && and a free function,
+\ref when_all for example. Both work similar however the free functions are
+capable of working with nested sequences as described in
+\ref tutorial-connecting-continuables-nested.
+
+\note Connections between continuable_base objects are ensured to be
+      <B>thread-safe</B> and <B>wait-free</B> by library design
+      (when assuming that `std::call_once` is wait-free - which depends
+      on the toolchain).
+
+\section tutorial-connecting-continuables-aggregated Using aggregated strategies
+
+Aggregated strategies will call the result handler with the compound result of
+all connected \ref continuable_base objects.
+
+The compound result is deduced as following. Every continuable_base maps its
+result to the result itself as shown below. When multiple continuable_base
+objects are connected on the same depth, the result is joined.
+See \ref tutorial-connecting-continuables-nested for details.
+
+|          Continuation type        |   In tuple like | In container (`std::vector`) |
+| : ------------------------------- | : --------- | : ------------------------------ |
+| `continuable_base with <>`        | `<none>`    | `<none>`                         |
+| `continuable_base with <Arg>`     | `Arg`       | `Arg`                            |
+| `continuable_base with <Args...>` | `Args...`   | `std::tuple<Args...>`            |
+
+\subsection tutorial-connecting-continuables-aggregated-all Using the all connection
+
+The *all* strategy invokes all connected continuable at once, it tries to resolve
+the connected \ref continuable_base objects as fast as possible.
+It is possible to connect multiple \ref continuable_base objects together
+through the *all* strategy by using \ref continuable_base::operator && or
+\ref when_all. In contrast to the operator the free functions are capable of
+workin with plain types and deeply nested \ref continuable_base objects as
+described in \ref tutorial-connecting-continuables-nested .
+
+\code{.cpp}
+(http_request("github.com") && http_request("travis-ci.org") &&
+ http_request("atom.io"))
+  .then([](std::string github, std::string travis,
+           std::string atom) {
+    // The callback is called with the
+    // response of github, travis and atom.
+  });
+\endcode
+
+\subsection tutorial-connecting-continuables-aggregated-seq Using the sequential connection
+
+The *sequential* strategy invokes all connected continuable one after each other,
+it tries to resolve the next connected \ref continuable_base objects as soon
+as the previous one was resolved.
+It is possible to connect multiple \ref continuable_base objects together
+through the *sequential* strategy by using \ref continuable_base::operator>> or
+\ref when_seq.
+
+\code{.cpp}
+(http_request("github.com") >> http_request("travis-ci.org") >>
+ http_request("atom.io"))
+  .then([](std::string github, std::string travis,
+           std::string atom) {
+    // The requests are invoked sequentially instead
+    // of requesting all at once.
+  });
+\endcode
+
+\section tutorial-connecting-continuables-any Using the any connection
+
+The any connection strategy is completely different from the two introduces
+before: It calls the result handler with the first result or exception
+available. All \ref continuable_base objects are required to have the same
+types of arguments.
+
+\code{.cpp}
+(http_request("github.com") || http_request("travis-ci.org") ||
+ http_request("atom.io"))
+  .then([](std::string github_or_travis_or_atom) {
+    // The callback is called with the first response
+    // of either github, travis or atom.
+  });
+\endcode
+
+\section tutorial-connecting-continuables-mixed Mixing different strategies
+
+Mixing different strategies through operators and free functions
+is natively supported as shown below:
+
+\code{.cpp}
+(http_request("github.com") &&
+ (http_request("travis-ci.org") || http_request("atom.io")))
+    .then([](std::string github, std::string travis_or_atom) {
+      // The callback is called with the response of
+      // github for sure and the second parameter represents
+      // the response of travis or atom.
+    });
+\endcode
+
+\section tutorial-connecting-continuables-nested Nested continuables and plain types
+
+For every operator that was shown above, there exists a free function
+that provides at least the same functionality:
+
+\code{.cpp}
+cti::when_all(http_request("github.com"), http_request("travis-ci.org"));
+cti::when_any(http_request("github.com"), http_request("travis-ci.org"));
+cti::when_seq(http_request("github.com"), http_request("travis-ci.org"));
+\endcode
+
+Additionally the free functions are capable of working with continuables deeply
+nested inside tuple like objects (`std::tuple`, `std::pair` and `std::array`)
+as well as homogeneous containers (`std::vector`, `std::list` etc.).
+
+\code{.cpp}
+std::tuple<std::vector<cti::continuable<int>>> outstanding;
+// ...
+
+cti::when_all(std::make_tuple(std::move(outstanding),
+                              http_request("github.com")))
+      .then([](std::tuple<std::tuple<std::vector<int>>,
+                          std::string> result) {
+        // ...
+      });
+\endcode
+
+Values which are given to such a free function are preserved and
+later passed to the result handler:
+
+\code{.cpp}
+cti::when_seq(0, 1,
+              cti::make_ready_continuable(2, 3),
+              4, 5)
+      .then([](int r0, int r1, int r2,
+               int r3, int r4) {
+        // ...
+      });
+\endcode
+
+When combining both capabilities it's even possible do something like this:
+
+\code{.cpp}
+cti::when_all(
+    cti::make_ready_continuable(0, 1),
+    2, //< See this plain value
+    cti::populate(cti::make_ready_continuable(3),  // Creates a runtime
+                  cti::make_ready_continuable(4)), // sized container.
+    std::make_tuple(std::make_tuple(cti::make_ready_continuable(5))))
+      .then([](int r0, int r1, int r2, std::vector<int> r34,
+               std::tuple<std::tuple<int>> r5) {
+        // ...
+      });
+\endcode
+
+\section tutorial-connecting-continuables-populate Populating a container from arbitrary continuables
+
+\ref populate mainly helps to create a homogeneous container from
+a runtime known count of continuables which type isn't exactly known.
+All continuables which are passed to this function should be originating
+from the same source or a method called with the same types of arguments:
+
+\code{.cpp}
+// cti::populate just creates a std::vector from the two continuables.
+auto v = cti::populate(cti::make_ready_continuable(0),
+                       cti::make_ready_continuable(1));
+
+for (int i = 2; i < 5; ++i) {
+  // It is possible to  add more continuables
+  // to the container afterwards
+  container.emplace_back(cti::make_ready_continuable(i));
+}
+
+cti::when_all(std::move(v))
+  .then([](std::vector<int> resolved) {
+    // ...
+  });
+\endcode
+
+*/
+}

doc/tutorial-creating-continuables.dox

@@ -0,0 +1,142 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page tutorial-creating-continuables Creating continuables
+\brief Explains how to create a \ref continuable_base.
+
+\tableofcontents
+
+A \ref continuable is an arbitrary instantiation of a \ref continuable_base,
+it represents the main class of the library and makes it possible to build up
+an asynchronous call hierarchy. When dealing with continuables we usually don't
+know its exact type for avoiding expensive type erasure.
+
+The \ref continuable_base is convertible to a \ref continuable which represents
+a specified type of the \ref continuable_base on the cost of a type erasure.
+
+\section tutorial-creating-continuables-ready From a value or exception
+
+The library provides \ref make_ready_continuable which may be used to create a
+\ref continuable_base from an arbitrary amount of values:
+
+\code{.cpp}
+auto one = cti::make_ready_continuable(0);
+
+cti::continuable<int, float, char> three =
+  cti::make_ready_continuable(0, 1.f, '2');
+\endcode
+
+\note In most situations you will never use \ref make_ready_continuable
+      because the library is capable of working with plain values
+      directly and thus this burdens unnecessary overhead.
+
+Additionally a \ref continuable_base which resolves with an exception may be
+created through \ref make_exceptional_continuable.
+
+\code{.cpp}
+cti::continuable<int> c = cti::make_exceptional_continuable(std::exception{});
+\endcode
+
+\section tutorial-creating-continuables-promises From a promise taking callable
+
+The main function for creating a \ref continuable_base is \ref make_continuable
+which must be invoked with the types of arguments it resolves to.
+It accepts a callable object which accepts an arbitrary object
+(the \ref promise_base). The \ref promise_base is created by the library and
+then passed to the given callback. This is in contrast to the usage of the
+standard `std::promise` which is created by the user.
+
+The \ref promise_base exposes methods to resolve it through result values or
+through an exception. Below we implement pseudo `http_request` function
+which resolves the request asynchronously trough a `std::string`.
+
+\code{.cpp}
+auto http_request(std::string url) {
+  return cti::make_continuable<std::string>(
+    [url = std::move(url)](auto&& promise) {
+      // Resolve the promise upon completion of the task.
+      promise.set_value("<html> ... </html>");
+
+      // Or promise.set_exception(...);
+    });
+}
+\endcode
+
+An alternative would be a \ref continuable_base with a result of zero arguments:
+
+\code{.cpp}
+auto wait_for(std::chrono::milliseconds duration) {
+  return cti::make_continuable<void>([](auto&& promise) {
+  //                           ^^^^
+
+  // Resolve the promise later when the duration is over
+  promise.set_value();
+});
+\endcode
+
+A \ref continuable_base may resolve with an arbitrary count of result values:
+
+\code{.cpp}
+auto resolve_sth() {
+  return cti::make_continuable<int, int, float, char>(
+    [](auto&& promise) {
+      promise.set_value(0, 1, 2.f, '3');
+    });
+\endcode
+
+\warning A \ref promise_base is only usable once and thus invalidated
+         after it was resolved!
+
+A \ref promise_base always exposes a call operator for resolving it as
+like when using \ref promise_base::set_value or
+\ref promise_base::set_exception. See \ref promise_base for details.
+
+\note In order to make proper use of a \ref promise_base you should
+      move it around, store it for later use and resolve it when
+      the asynchronous task was finished or rejected.
+
+\section tutorial-creating-continuables-invocation The continuable invocation model
+
+An asynchronous call hierarchy that is stored inside the \ref continuable_base
+is executed when its result is requested (lazy evaluation) in contrast to
+other commonly used implementations such as `std::future` which execute the
+asynchronous call hierarchy instantly on creation (eager evaluation).
+
+The lazy evaluation strategy used by continuables has many benefits over
+eager evaluation that is used by other common implementations:
+- prevention of side effects
+- evasion of race conditions
+- ensured deterministic behaviour.
+
+The asynchronous call hierarchy is started when the \ref continuable_base is
+destructed or the \ref continuable_base::done method is called.
+It is possible to disable the automatic start through calling
+\ref continuable_base::freeze on the corresponding \ref continuable_base.
+
+\attention A \ref continuable_base is not designed to be stored permanently,
+           make sure you call \ref continuable_base::freeze before storing it
+           and start the continuation chain later through calling
+           \ref continuable_base::done.
+
+*/
+}

doc/tutorial-promisify-continuables.dox

@@ -0,0 +1,99 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page tutorial-promisify-continuables Promisify functions
+\brief Explains how to promisify callback taking functions into a \ref continuable_base.
+
+\tableofcontents
+
+\section tutorial-promisify-continuables-promisify Promisification and continuables
+
+The promisification has a longer history in the JavaScript world where
+the legacy way of asynchronous programming was the usage of callbacks of the
+form \code{.js}function(error, result...)\endcode. The ideal way of dealing
+with such an asynchronous result is to return a promise and soon utility
+helpers were provided to do so.
+
+The usage of callbacks to represent an asynchronous result is still a popular
+way nowadays. Thus the library provides the \ref promisify helper class
+which makes it possible to convert callback taking functions of various styles
+into one that returns a \ref continuable_base instead.
+
+\note Providing promisified APIs for other popular libraries is out of
+      scope for this library. However contributions are highly welcome to
+      add more conversion helpers for other commonly used callback styles.
+
+\section tutorial-promisify-continuables-boost Promisify boost::asio
+
+The default callback style is something like
+\code{.js}function(error, result...)\endcode as described above.
+Continuable offers the \ref promisify::from method for such callback styles.
+
+See an example of how to promisify boost asio's `async_resolve` below:
+
+\code{.cpp}
+auto async_resolve(std::string host, std::string service) {
+  return cti::promisify<asio::ip::udp::resolver::iterator>::from(
+      [&](auto&&... args) {
+        resolver_.async_resolve(std::forward<decltype(args)>(args)...);
+      },
+      std::move(host), std::move(service));
+}
+\endcode
+
+Then it should be possible to use `asio::async_resolve` like this:
+
+\code{.cpp}
+async_resolve("127.0.0.1", "daytime")
+  .then([](udp::resolver::iterator iterator) {
+    // ...
+  });
+\endcode
+
+
+\section tutorial-promisify-continuables-boost-ct asio and boost::asio async completion tokens
+
+Since version 4.0.0 continuable also supports asio async initiation tokens.
+
+- Boost 1.70 or asio 1.13.0 is required for the async initiation
+- Until boost 1.72 or asio 1.16.0 overhead through an additional type
+  erasure is added. It is recommended to update to those versions.
+
+The special static variable \ref cti::use_continuable can be appended to any
+(boost) asio function that accepts a callback to make it return a \ref continuable_base.
+
+\code{.cpp}
+#include <continuable/continuable.hpp>
+#include <continuable/external/asio.hpp>
+#include <asio.hpp>
+
+// ...
+
+asio::tcp::resolver resolver(...);
+resolver.async_resolve("127.0.0.1", "daytime", cti::use_continuable)
+  .then([](asio::udp::resolver::iterator iterator) {
+    // ...
+  });
+\endcode
+*/
+}

doc/tutorial-transforming-continuables.dox

@@ -0,0 +1,84 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page tutorial-transforming-continuables Transforming continuables
+\brief Explains the conversion into other types such as `std::future`.
+
+\tableofcontents
+
+\section tutorial-transforming-continuables-transforms Transforms in general
+
+Sometimes it's required to change a \ref continuable_base object by its whole.
+Thus the library offers the ability to apply a transformation to any
+\ref continuable_base through using \link continuable_base::apply apply \endlink.
+
+A transformation is a callable object that accepts a \ref continuable_base
+and returns an arbitrary object
+
+The library provides several transforms already as part of the
+\ref cti::transforms namespace.
+
+\section tutorial-transforming-continuables-wait Synchronous wait
+
+The library is capable of converting every asynchronous control flow
+into a synchronous one through \ref transforms::wait, \ref transforms::wait_for
+and \ref transforms::wait_until.
+
+\code{.cpp}
+std::string response = http_request("github.com")
+  .apply(cti::transforms::wait());
+
+std::string response = http_request("github.com")
+  .apply(cti::transforms::wait_for(std::chrono::seconds(5)));
+
+std::string response = http_request("github.com")
+  .apply(cti::transforms::wait_until(...));
+\endcode
+
+The current thread will be blocked until the result has arrived
+
+\section tutorial-transforming-continuables-future Conversion into std::future
+
+The library is capable of converting (*futurizing*) every continuable into a
+fitting `std::future` through the \ref transforms::to_future transform:
+
+\code{.cpp}
+std::future<std::string> future = http_request("github.com")
+  .then([](std::string response) {
+    // Do sth...
+    return http_request("travis-ci.org") || http_request("atom.io");
+  })
+  .apply(cti::transforms::to_future());
+// ^^^^^^^^
+\endcode
+
+Multiple arguments which can't be handled by `std::future` itself are
+converted into `std::tuple`, see \ref transforms::to_future for details.
+
+\code{.cpp}
+std::future<std::tuple<std::string, std::string>> future =
+  (http_request("travis-ci.org") && http_request("atom.io"))
+    .apply(cti::transforms::to_future());
+\endcode
+*/
+}

doc/tutorial.dox

@@ -0,0 +1,41 @@
+/*
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+
+namespace cti {
+/** \page tutorial Tutorial
+\brief An introduction for using the continuable library.
+
+This tutorial will give a short overview about using the library.
+We assume that the library is available in your current environment,
+if not, follow the \ref installation section in order to get it to work.
+
+This tutorial is split across multiple chapters which should be read in order:
+
+- \subpage tutorial-creating-continuables --- \copybrief tutorial-creating-continuables
+- \subpage tutorial-chaining-continuables --- \copybrief tutorial-chaining-continuables
+- \subpage tutorial-connecting-continuables --- \copybrief tutorial-connecting-continuables
+- \subpage tutorial-transforming-continuables --- \copybrief tutorial-transforming-continuables
+- \subpage tutorial-awaiting-continuables --- \copybrief tutorial-awaiting-continuables
+- \subpage tutorial-promisify-continuables --- \copybrief tutorial-promisify-continuables
+
+*/
+}

examples/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_subdirectory(example-asio)
 add_subdirectory(example-ai)
+add_subdirectory(example-slideshow)

examples/example-ai/example-ai.cpp

@@ -7,7 +7,7 @@
                     https://github.com/Naios/continuable
                                    v3.0.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

examples/example-asio/CMakeLists.txt

@@ -1,15 +1,28 @@
+add_library(asio-example-deps INTERFACE)
+
+target_include_directories(asio-example-deps
+  INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR})
+
+target_link_libraries(asio-example-deps
+  INTERFACE
+    asio
+    continuable)
+
 add_executable(example-asio
     ${CMAKE_CURRENT_LIST_DIR}/example-asio.cpp)
 
-target_include_directories(example-asio
-  PRIVATE
-    ${CMAKE_CURRENT_LIST_DIR})
-
 target_link_libraries(example-asio
   PRIVATE
-    asio
+    asio-example-deps)
-    continuable)
 
 target_compile_definitions(example-asio
   PUBLIC
     -DCONTINUABLE_WITH_NO_EXCEPTIONS)
+
+add_executable(example-asio-integration
+    ${CMAKE_CURRENT_LIST_DIR}/example-asio-integration.cpp)
+
+target_link_libraries(example-asio-integration
+  PRIVATE
+    asio-example-deps)

examples/example-asio/example-asio-integration.cpp

@@ -0,0 +1,176 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#include <asio.hpp>
+
+#include <continuable/continuable.hpp>
+#include <continuable/external/asio.hpp>
+
+// Queries the NIST daytime service and prints the current date and time
+void daytime_service();
+
+// Checks that a timer async_wait returns successfully
+void successful_async_wait();
+
+// Checks that a cancelled timer async_wait fails with
+// `asio::error::operation_aborted` and is converted to a default constructed
+// cti::exception_t.
+void cancelled_async_wait();
+
+// Indicates fatal error due to an unexpected failure in the continuation chain.
+void unexpected_error(cti::exception_t);
+
+// Check that the failure was an aborted operation, as expected.
+void check_aborted_operation(cti::exception_t);
+
+// Use a strand as executor
+void using_strand();
+
+int main(int, char**) {
+  daytime_service();
+
+  successful_async_wait();
+  cancelled_async_wait();
+
+  using_strand();
+
+  return 0;
+}
+
+void daytime_service() {
+  using asio::ip::tcp;
+  asio::io_context ioc(1);
+  tcp::resolver resolver(ioc);
+  tcp::socket socket(ioc);
+  std::string buf;
+
+  resolver.async_resolve("time.nist.gov", "daytime", cti::use_continuable)
+      .then([&socket](tcp::resolver::results_type endpoints) {
+        return asio::async_connect(socket, endpoints, cti::use_continuable);
+      })
+      .then([&socket, &buf] {
+        return asio::async_read_until(socket, asio::dynamic_buffer(buf), '\n',
+                                      cti::use_continuable);
+      })
+      .then([&buf](std::size_t) {
+        puts("Continuation successfully got a daytime response:");
+        puts(buf.c_str());
+      })
+      .fail(&unexpected_error);
+
+  ioc.run();
+}
+
+void successful_async_wait() {
+  asio::io_context ioc(1);
+  asio::steady_timer t(ioc);
+
+  t.expires_after(std::chrono::seconds(1));
+
+  t.async_wait(cti::use_continuable)
+      .then([] {
+        puts("Continuation succeeded after 1s as expected!");
+      })
+      .fail(&unexpected_error);
+
+  ioc.run();
+}
+
+void cancelled_async_wait() {
+  asio::io_context ioc(1);
+  asio::steady_timer t(ioc);
+
+  t.expires_after(std::chrono::seconds(999));
+
+  t.async_wait(cti::use_continuable)
+      .then([] {
+        puts("This should never be called");
+        std::terminate();
+      })
+      .fail(&check_aborted_operation);
+
+  t.cancel_one();
+  ioc.run();
+}
+
+void unexpected_error(cti::exception_t e) {
+  if (!bool(e)) {
+    puts("Continuation failed with unexpected cancellation!");
+    std::terminate();
+  }
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+  try {
+    std::rethrow_exception(e);
+  } catch (std::exception const& ex) {
+    puts("Continuation failed with unexpected exception");
+    puts(ex.what());
+  } catch (...) {
+    // Rethrow the exception to the asynchronous unhandled exception handler
+    std::rethrow_exception(std::current_exception());
+  }
+#else
+  puts("Continuation failed with unexpected error");
+  puts(e.message().data());
+#endif
+  std::terminate();
+}
+
+void check_aborted_operation(cti::exception_t ex) {
+  if (bool(ex)) {
+    unexpected_error(ex);
+  } else {
+    puts("Continuation failed due to aborted async operation, as expected.");
+  }
+}
+
+template <typename T>
+auto through_post(T& postable) {
+  return [&postable](auto&& work) mutable {
+    asio::post(postable, std::forward<decltype(work)>(work));
+  };
+}
+
+void using_strand() {
+  asio::io_context ioc(1);
+  asio::io_context::strand strand(ioc);
+
+  asio::post(strand, cti::use_continuable).then([]() {
+    puts("Dispatched through initiation token");
+  });
+
+  cti::async_on(
+      []() mutable {
+        puts("Dispatched through executor");
+      },
+      through_post(strand));
+
+  ioc.run();
+}

examples/example-asio/example-asio.cpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.0.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -34,12 +34,30 @@
 #include <string>
 #include <system_error>
 
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#include <exception>
+#endif
+
 #include <asio.hpp>
 
 #include <continuable/continuable.hpp>
 
 using namespace std::chrono_literals;
 
+inline auto error_code_remapper() {
+  return [](auto&& promise, asio::error_code e, auto&&... args) {
+    if (e) {
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+      promise.set_exception(std::make_exception_ptr(e));
+#else
+      promise.set_exception(cti::exception_t(e.value(), e.category()));
+#endif
+    } else {
+      promise.set_value(std::forward<decltype(args)>(args)...);
+    }
+  };
+}
+
 struct functional_io_service {
   asio::io_context service_;
   asio::ip::udp::resolver resolver_;
@@ -49,7 +67,11 @@ struct functional_io_service {
 
   auto trough_post() noexcept {
     return [&](auto&& work) mutable {
-      asio::post(service_, std::forward<decltype(work)>(work));
+      asio::post(service_,
+                 [work = std::forward<decltype(work)>(work)]() mutable {
+                   std::move(work)();
+                   // .. or: work.set_value();
+                 });
     };
   }
 
@@ -61,7 +83,8 @@ struct functional_io_service {
   }
 
   auto async_resolve(std::string host, std::string service) {
-    return cti::promisify<asio::ip::udp::resolver::iterator>::from_asio(
+    return cti::promisify<asio::ip::udp::resolver::iterator>::with(
+        error_code_remapper(),
         [&](auto&&... args) {
           resolver_.async_resolve(std::forward<decltype(args)>(args)...);
         },
@@ -89,7 +112,7 @@ int main(int, char**) {
         // auto socket = std::make_shared<udp::socket>(service);
         // socket->async_send_to()
       })
-      .fail([](cti::error_type /*error*/) {
+      .fail([](cti::exception_t /*error*/) {
         // ...
       });
 

examples/example-slideshow/CMakeLists.txt

@@ -0,0 +1,5 @@
+add_executable(example-slideshow
+  ${CMAKE_CURRENT_LIST_DIR}/example-slideshow.cpp)
+target_link_libraries(example-slideshow
+  PRIVATE
+    continuable)

examples/example-slideshow/example-slideshow.cpp

@@ -1,5 +1,5 @@
 /*
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -13,7 +13,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -25,43 +25,32 @@
 #include "continuable/continuable.hpp"
 
 cti::continuable<std::string> http_request(std::string /*url*/) {
-  return [](auto&& callback) {
+  return cti::make_ready_continuable<std::string>("<html>...</html>");
-    // ...
-    callback.set_value("<html>...</html>");
-  };
 }
 
 struct ResultSet {};
 struct Buffer {};
 
 cti::continuable<ResultSet> mysql_query(std::string /*url*/) {
-  return [](auto&& callback) {
+  return cti::make_ready_continuable(ResultSet{});
-    // ...
-    callback.set_value(ResultSet{});
-  };
 }
 
 cti::continuable<Buffer> read_file(std::string /*url*/) {
-  return [](auto&& callback) {
+  return cti::make_ready_continuable(Buffer{});
-    // ...
-    callback.set_value(Buffer{});
-  };
 }
 
-struct a {
+struct functional_executor {
   auto post() const {
     return [](auto&&) {};
   }
 };
 
 int main(int, char**) {
-  a e;
+  functional_executor e;
   auto executor = &e;
+
   // clang-format off
 
-
-  // ----------
-
   (http_request("github.com") && http_request("atom.io"))
     .then([] (std::string /*github*/, std::string /*atom*/) {
       // ...
@@ -71,23 +60,15 @@ int main(int, char**) {
       // ...
     }, executor->post());
 
-  // ----------
+  // clang-format on
 
-  auto c1 =      http_request("github.com") && http_request("atom.io")         ;
+  http_request("github.com") && http_request("atom.io");
 
+  http_request("github.com") || http_request("atom.io");
 
+  http_request("github.com") >> http_request("atom.io");
 
-  auto c2 =      http_request("github.com") || http_request("atom.io")         ;
+  // clang-format off
-
-
-
-  auto c3 =      http_request("github.com") >> http_request("atom.io")         ;
-
-  (void)c1;
-  (void)c2;
-  (void)c3;
-
-  // ----------
 
   read_file("entries.csv")
     .then([] (Buffer /*buffer*/) {
@@ -98,8 +79,7 @@ int main(int, char**) {
       // ...
     });
 
-  // ----------
-
   // clang-format on
+
   return 0;
 }

include/continuable/continuable-base.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -32,60 +32,35 @@
 #define CONTINUABLE_BASE_HPP_INCLUDED
 
 #include <cassert>
-#include <cstdint>
+#include <cstddef>
 #include <type_traits>
 #include <utility>
+#include <continuable/continuable-primitives.hpp>
+#include <continuable/continuable-result.hpp>
+#include <continuable/detail/connection/connection-all.hpp>
+#include <continuable/detail/connection/connection-any.hpp>
+#include <continuable/detail/connection/connection-seq.hpp>
+#include <continuable/detail/connection/connection.hpp>
+#include <continuable/detail/core/base.hpp>
+#include <continuable/detail/core/types.hpp>
+#include <continuable/detail/features.hpp>
+#include <continuable/detail/utility/traits.hpp>
+#include <continuable/detail/utility/util.hpp>
 
-#include <continuable/detail/awaiting.hpp>
+#if defined(CONTINUABLE_HAS_COROUTINE)
-#include <continuable/detail/base.hpp>
+#  include <continuable/detail/other/coroutines.hpp>
-#include <continuable/detail/composition-all.hpp>
+#endif // defined(CONTINUABLE_HAS_COROUTINE)
-#include <continuable/detail/composition-any.hpp>
-#include <continuable/detail/composition-seq.hpp>
-#include <continuable/detail/composition.hpp>
-#include <continuable/detail/traits.hpp>
-#include <continuable/detail/types.hpp>
-#include <continuable/detail/util.hpp>
 
 namespace cti {
-/// Represents a tag which can be placed first in a signature
+/// \defgroup Base Base
-/// in order to overload callables with the asynchronous result
+/// provides classes and functions to create continuable_base objects.
-/// as well as an error.
+/// \{
-///
-/// See the example below:
-/// ```cpp
-/// struct my_callable {
-///   void operator() (std::string result) {
-///     // ...
-///   }
-///   void operator() (cti::dispatch_error_tag, cti::error_type) {
-///     // ...
-///   }
-/// };
-///
-/// // Will receive errors and results
-/// continuable.next(my_callable{});
-/// ```
-///
-/// \note see continuable::next for details.
-///
-/// \since 2.0.0
-using detail::types::dispatch_error_tag;
-
-/// Represents the type that is used as error type
-///
-/// By default this type deduces to `std::exception_ptr`.
-/// If `CONTINUABLE_WITH_NO_EXCEPTIONS` is defined the type
-/// will be a `std::error_condition`.
-/// A custom error type may be set through
-/// defining `CONTINUABLE_WITH_CUSTOM_ERROR_TYPE`.
-///
-/// \since 2.0.0
-using detail::types::error_type;
 
 /// Deduces to a true_type if the given type is a continuable_base.
 ///
 /// \since 3.0.0
-using detail::base::is_continuable;
+template <typename T>
+using is_continuable = detail::base::is_continuable<T>;
 
 /// The main class of the continuable library, it provides the functionality
 /// for chaining callbacks and continuations together to a unified hierarchy.
@@ -105,8 +80,7 @@ using detail::base::is_continuable;
 /// \note Nearly all methods of the cti::continuable_base are required to be
 ///       called as r-value. This is required because the continuable carries
 ///       variables which are consumed when the object is transformed as part
-///       of a method call. You may copy a continuable which underlying
+///       of a method call.
-///       storages are copyable to split the call hierarchy into multiple parts.
 ///
 /// \attention The continuable_base objects aren't intended to be stored.
 ///            If you want to store a continuble_base you should always
@@ -118,6 +92,10 @@ template <typename Data, typename Annotation>
 class continuable_base {
 
   /// \cond false
+  using ownership = detail::util::ownership;
+
+  using annotation_trait = detail::annotation_trait<Annotation>;
+
   template <typename, typename>
   friend class continuable_base;
   friend struct detail::base::attorney;
@@ -125,25 +103,41 @@ class continuable_base {
   // The continuation type or intermediate result
   Data data_;
   // The transferable state which represents the validity of the object
-  detail::util::ownership ownership_;
+  ownership ownership_;
   /// \endcond
 
   /// Constructor accepting the data object while erasing the annotation
-  explicit continuable_base(Data data, detail::util::ownership ownership)
+  explicit continuable_base(Data data, ownership ownership)
-      : data_(std::move(data)), ownership_(std::move(ownership)) {
+    : data_(std::move(data))
-  }
+    , ownership_(std::move(ownership)) {}
 
 public:
   /// Constructor accepting the data object while erasing the annotation
-  explicit continuable_base(Data data) : data_(std::move(data)) {
+  explicit continuable_base(Data data)
-  }
+    : data_(std::move(data)) {}
 
   /// Constructor accepting any object convertible to the data object,
   /// while erasing the annotation
-  template <typename OData, std::enable_if_t<std::is_convertible<
+  template <typename OtherData,
-                                std::decay_t<OData>, Data>::value>* = nullptr>
+            std::enable_if_t<detail::base::can_accept_continuation<
-  continuable_base(OData&& data) : data_(std::forward<OData>(data)) {
+                Data, Annotation,
-  }
+                detail::traits::unrefcv_t<OtherData>>::value>* = nullptr>
+  /* implicit */ continuable_base(OtherData&& data)
+    : data_(
+          detail::base::proxy_continuable<Annotation,
+                                          detail::traits::unrefcv_t<OtherData>>(
+              std::forward<OtherData>(data))) {}
+
+  /// Constructor taking the data of other continuable_base objects
+  /// while erasing the hint.
+  ///
+  /// This constructor makes it possible to replace the internal data object of
+  /// the continuable by any object which is useful for type-erasure.
+  template <typename OData,
+            std::enable_if_t<std::is_convertible<
+                detail::traits::unrefcv_t<OData>, Data>::value>* = nullptr>
+  /* implicit */ continuable_base(continuable_base<OData, Annotation>&& other)
+    : data_(std::move(other).consume()) {}
 
   /// Constructor taking the data of other continuable_base objects
   /// while erasing the hint.
@@ -151,16 +145,15 @@ public:
   /// This constructor makes it possible to replace the internal data object of
   /// the continuable by any object which is useful for type-erasure.
   template <typename OData, typename OAnnotation>
-  continuable_base(continuable_base<OData, OAnnotation>&& other)
+  /* implicit */ continuable_base(continuable_base<OData, OAnnotation>&& other)
-      : continuable_base(std::move(other).materialize().consume_data()) {
+    : continuable_base(std::move(other).finish().consume()) {}
-  }
 
   /// \cond false
   continuable_base(continuable_base&&) = default;
-  continuable_base(continuable_base const&) = default;
+  continuable_base(continuable_base const&) = delete;
 
   continuable_base& operator=(continuable_base&&) = default;
-  continuable_base& operator=(continuable_base const&) = default;
+  continuable_base& operator=(continuable_base const&) = delete;
   /// \endcond
 
   /// The destructor automatically invokes the continuable_base
@@ -232,12 +225,17 @@ public:
   /// | `Arg`                      | `continuable_base with <Arg>`             |
   /// | `std::pair<First, Second>` | `continuable_base with <First, Second>`   |
   /// | `std::tuple<Args...>`      | `continuable_base with <Args...>`         |
+  /// | `cti::result<Args...>`     | `continuable_base with <Args...>`         |
   /// | `continuable_base<Arg...>` | `continuable_base with <Args...>`         |
   ///          Which means the result type of the continuable_base is equal to
   ///          the plain types the callback returns (`std::tuple` and
   ///          `std::pair` arguments are unwrapped).
   ///          A single continuable_base as argument is resolved and the result
   ///          type is equal to the resolved continuable_base.
+  ///          A cti::result can be used to cancel the continuation or to
+  ///          transition to the exception handler.
+  ///          The special unwrapping of types can be disabled through wrapping
+  ///          such objects through a call to cti::make_plain.
   ///          Consider the following examples:
   /// ```cpp
   /// http_request("github.com")
@@ -259,6 +257,17 @@ public:
   /// http_request("github.com")
   ///   .then([](std::string github) { return http_request("atom.io"); })
   ///   .then([](std::string atom) { }); // <std::string>
+  ///
+  /// http_request("example.com")
+  ///   .then([](std::string content) -> result<std::string> {
+  ///     return rethrow(std::make_exception_ptr(std::exception{}));
+  ///   })
+  ///   .fail([] -> result<std::string> {
+  ///     return recover("Hello World!");
+  ///   })
+  ///   .then([](std::string content) -> result<std::string> {
+  ///     return cancel();
+  ///   })
   /// ```
   ///
   /// \since 1.0.0
@@ -267,7 +276,7 @@ public:
             E&& executor = detail::types::this_thread_executor_tag{}) && {
     return detail::base::chain_continuation<detail::base::handle_results::yes,
                                             detail::base::handle_errors::no>(
-        std::move(*this).materialize(), std::forward<T>(callback),
+        std::move(*this).finish(), std::forward<T>(callback),
         std::forward<E>(executor));
   }
 
@@ -293,7 +302,7 @@ public:
   template <typename OData, typename OAnnotation>
   auto then(continuable_base<OData, OAnnotation>&& continuation) && {
     return std::move(*this).then(
-        detail::base::wrap_continuation(std::move(continuation).materialize()));
+        detail::base::wrap_continuation(std::move(continuation).finish()));
   }
 
   /// Main method of the continuable_base to catch exceptions and error codes
@@ -308,12 +317,18 @@ public:
   /// ```cpp
   /// http_request("github.com")
   ///   .then([](std::string github) { })
-  ///   .fail([](std::exception_ptr ptr) {
+  ///   .fail([](std::exception_ptr ep) {
-  ///     // Handle the error here
+  ///     // Check whether the exception_ptr is valid (not default constructed)
-  ///     try {
+  ///     // if bool(ep) == false this means that the operation was cancelled
-  ///       std::rethrow_exception(ptr);
+  ///     // by the user or application (promise.set_canceled() or
-  ///     } catch (std::exception& e) {
+  ///     // make_cancelling_continuable()).
-  ///       e.what(); // Handle the exception
+  ///     if (ep) {
+  ///       // Handle the error here
+  ///       try {
+  ///         std::rethrow_exception(ep);
+  ///       } catch (std::exception& e) {
+  ///         e.what(); // Handle the exception
+  ///       }
   ///     }
   ///   });
   /// ```
@@ -333,14 +348,26 @@ public:
   /// \returns Returns a continuable_base with an asynchronous return type
   ///          depending on the previous result type.
   ///
+  /// \attention The given exception type exception_t can be passed to the
+  ///            handler in a default constructed state <br>`bool(e) == false`.
+  ///            This always means that the operation was cancelled by the user,
+  ///            possibly through:
+  ///              - \ref promise_base::set_canceled
+  ///              - \ref make_cancelling_continuable
+  ///              - \ref result::set_canceled
+  ///              - \ref cancel<br>
+  ///            In that case the exception can be ignored safely (but it is
+  ///            recommended not to proceed, although it is possible to
+  ///            recover from the cancellation).
   ///
   /// \since 2.0.0
   template <typename T, typename E = detail::types::this_thread_executor_tag>
   auto fail(T&& callback,
             E&& executor = detail::types::this_thread_executor_tag{}) && {
-    return detail::base::chain_continuation<detail::base::handle_results::no,
+    return detail::base::chain_continuation<
-                                            detail::base::handle_errors::plain>(
+        detail::base::handle_results::no, detail::base::handle_errors::forward>(
-        std::move(*this).materialize(), std::forward<T>(callback),
+        std::move(*this).finish(),
+        detail::base::strip_exception_arg(std::forward<T>(callback)),
         std::forward<E>(executor));
   }
 
@@ -362,9 +389,11 @@ public:
   /// \since 2.0.0
   template <typename OData, typename OAnnotation>
   auto fail(continuable_base<OData, OAnnotation>&& continuation) && {
-    continuation.freeze();
+    return std::move(*this)                                     //
-    return std::move(*this).fail([continuation = std::move(continuation)](
+        .fail([continuation = std::move(continuation).freeze()] //
-        error_type) mutable { std::move(continuation).done(); });
+              (exception_t) mutable {
+                std::move(continuation).done(); //
+              });
   }
 
   /// A method which allows to use an overloaded callable for the error
@@ -378,7 +407,7 @@ public:
   ///   void operator() (std::string result) {
   ///     // ...
   ///   }
-  ///   void operator() (cti::dispatch_error_tag, cti::error_type) {
+  ///   void operator() (cti::exception_arg_t, cti::exception_t) {
   ///     // ...
   ///   }
   ///
@@ -399,22 +428,56 @@ public:
             E&& executor = detail::types::this_thread_executor_tag{}) && {
     return detail::base::chain_continuation<
         detail::base::handle_results::yes,
-        detail::base::handle_errors::forward>(std::move(*this).materialize(),
+        detail::base::handle_errors::forward>(std::move(*this).finish(),
                                               std::forward<T>(callback),
                                               std::forward<E>(executor));
   }
 
-  /// A method which allows to apply this continuable to the given callable.
+  /// Returns a continuable_base which continues its invocation through the
+  /// given executor.
   ///
-  /// \param transform A transform which shall accept this continuable
+  /// \returns Returns a continuable_base of the same type.
+  ///
+  /// \since 4.2.0
+  template <typename E>
+  auto via(E&& executor) && {
+    return std::move(*this).next(
+        [](auto&&... args) {
+          return make_result(std::forward<decltype(args)>(args)...);
+        },
+        std::forward<E>(executor));
+  }
+
+  /// Returns a continuable_base which will have its signature converted
+  /// to the given Args.
+  ///
+  /// A signature can only be converted if it can be partially applied
+  /// from the previous one as shown below:
+  /// ```cpp
+  /// continuable<long> c = make_ready_continuable(0, 1, 2).as<long>();
+  /// ```
+  ///
+  /// \returns Returns a continuable_base with an asynchronous return type
+  ///          matching the given Args.
+  ///
+  /// \since 4.0.0
+  template <typename... Args>
+  auto as() && {
+    return std::move(*this).then(detail::base::convert_to<Args...>{});
+  }
+
+  /// A method which allows to apply a callable object to this continuable.
+  ///
+  /// \param transform A callable objects that transforms a continuable
+  ///                  to a different object.
   ///
   /// \returns Returns the result of the given transform when this
   ///          continuable is passed into it.
   ///
-  /// \since 2.0.0
+  /// \since 4.0.0
   template <typename T>
   auto apply(T&& transform) && {
-    return std::forward<T>(transform)(std::move(*this).materialize());
+    return std::forward<T>(transform)(std::move(*this).finish());
   }
 
   /// The pipe operator | is an alias for the continuable::then method.
@@ -430,22 +493,6 @@ public:
     return std::move(*this).then(std::forward<T>(right));
   }
 
-  /// The pipe operator | is an alias for the continuable::apply method.
-  ///
-  /// \param transform The transformer which is applied.
-  ///
-  /// \returns See the corresponding continuable_base::apply method for the
-  ///          explanation of the return type.
-  ///
-  /// \note    You may create your own transformation through
-  ///          calling make_transformation.
-  ///
-  /// \since 3.0.0
-  template <typename T>
-  auto operator|(detail::types::transform<T> transform) && {
-    return std::move(*this).apply(std::move(transform));
-  }
-
   /// Invokes both continuable_base objects parallel and calls the
   /// callback with the result of both continuable_base objects.
   ///
@@ -473,8 +520,8 @@ public:
   ///   });
   /// ```
   ///
-  /// \note The continuable_base objects are invoked parallel on the
+  /// \note The continuable_base objects are invoked all at onve,
-  ///       current thread, because the `all` strategy tries to resolve
+  ///       because the `all` strategy tries to resolve
   ///       the continuations as fast as possible.
   ///       Sequential invocation is also supported through the
   ///       continuable_base::operator>> method.
@@ -482,8 +529,8 @@ public:
   /// \since 1.0.0
   template <typename OData, typename OAnnotation>
   auto operator&&(continuable_base<OData, OAnnotation>&& right) && {
-    return detail::composition::connect(
+    return detail::connection::connect(
-        detail::composition::composition_strategy_all_tag{}, std::move(*this),
+        detail::connection::connection_strategy_all_tag{}, std::move(*this),
         std::move(right));
   }
 
@@ -513,15 +560,15 @@ public:
   ///   });
   /// ```
   ///
-  /// \note The continuable_base objects are invoked parallel on the
+  /// \note The continuable_base objects are invoked all at once,
-  ///       current thread, however, the callback is only called once with
+  ///       however, the callback is only called once with
-  ///       the first result which becomes available.
+  ///       the first result or exception which becomes available.
   ///
   /// \since 1.0.0
   template <typename OData, typename OAnnotation>
   auto operator||(continuable_base<OData, OAnnotation>&& right) && {
-    return detail::composition::connect(
+    return detail::connection::connect(
-        detail::composition::composition_strategy_any_tag{}, std::move(*this),
+        detail::connection::connection_strategy_any_tag{}, std::move(*this),
         std::move(right));
   }
 
@@ -542,15 +589,15 @@ public:
   ///   });
   /// ```
   ///
-  /// \note The continuable_base objects are invoked sequential on the
+  /// \note The continuable_base objects are invoked sequential one after
-  ///       current thread. Parallel invocation is also supported through the
+  ///       the previous one was finished. Parallel invocation is also
-  ///       continuable_base::operator&& method.
+  ///       supported through the continuable_base::operator && method.
   ///
   /// \since 1.0.0
   template <typename OData, typename OAnnotation>
   auto operator>>(continuable_base<OData, OAnnotation>&& right) && {
-    return detail::composition::seq::sequential_connect(std::move(*this),
+    return detail::connection::seq::sequential_connect(std::move(*this),
-                                                        std::move(right));
+                                                       std::move(right));
   }
 
   /// Invokes the continuation chain manually even before the
@@ -564,7 +611,64 @@ public:
   ///
   /// \since 1.0.0
   void done() && {
-    detail::base::finalize_continuation(std::move(*this));
+    detail::base::finalize_continuation(std::move(*this).finish());
+  }
+
+  /// Materializes the continuation expression template and finishes
+  /// the current applied strategy such that the resulting continuable
+  /// will always be a concrete type and Continuable::is_concrete holds.
+  ///
+  /// This can be used in the case where we are chaining continuations lazily
+  /// through a strategy, for instance when applying operators for
+  /// expressing connections and then want to return a materialized
+  /// continuable_base which uses the strategy respectively.
+  /// ```cpp
+  /// auto do_both() {
+  ///   return (wait(10s) || wait_key_pressed(KEY_SPACE)).finish();
+  /// }
+  ///
+  /// // Without a call to finish() this would lead to
+  /// // an unintended evaluation strategy:
+  /// do_both() || wait(5s);
+  /// ```
+  ///
+  /// \note When using a type erased continuable_base such as
+  ///       `continuable<...>` this method doesn't need to be called
+  ///       since the continuable_base is materialized automatically
+  ///       on conversion.
+  ///
+  /// \since 4.0.0
+  auto finish() && {
+    return annotation_trait::finish(std::move(*this));
+  }
+
+  /// Returns true when the continuable can provide its result immediately,
+  /// and its lazy invocation would be side-effect free.
+  ///
+  /// \since 4.0.0
+  bool is_ready() const noexcept {
+    return annotation_trait::is_ready(*this);
+  }
+
+  /// Invalidates the continuable and returns its immediate invocation result.
+  ///
+  /// This method can be used to specialize the asynchronous control flow
+  /// based on whether the continuable_base is_ready at every time,
+  /// which is true for a continuable created through the following functions:
+  ///   - make_ready_continuable
+  ///   - make_exceptional_continuable
+  ///
+  /// \returns   A result<Args...> where Args... represent the current
+  ///            asynchronous parameters or the currently stored exception.
+  ///
+  /// \attention unpack requires that continuable_base::is_ready returned true
+  ///            in a previous check, otherwise its behaviour is unspecified.
+  ///
+  /// \since 4.0.0
+  auto unpack() && {
+    assert(ownership_.is_acquired());
+    assert(is_ready());
+    return detail::base::attorney::query(std::move(*this).finish());
   }
 
   /// Predicate to check whether the cti::continuable_base is frozen or not.
@@ -609,23 +713,82 @@ public:
     return std::move(*this);
   }
 
-#ifdef CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE
+  /// \cond false
+#if defined(CONTINUABLE_HAS_COROUTINE)
+  /// \endcond
+  /// Implements the operator for awaiting on continuables using `co_await`.
+  ///
+  /// The operator is only enabled if `CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE`
+  /// is defined and the toolchain supports experimental coroutines.
+  ///
+  /// The return type of the `co_await` expression is specified as following:
+  /// |          Continuation type        |          co_await returns          |
+  /// | : ------------------------------- | : -------------------------------- |
+  /// | `continuable_base with <>`        | `void`                             |
+  /// | `continuable_base with <Arg>`     | `Arg`                              |
+  /// | `continuable_base with <Args...>` | `std::tuple<Args...>`              |
+  ///
+  /// When exceptions are used the usage is as intuitive as shown below:
+  /// ```cpp
+  /// // Handling the exception isn't required and
+  /// // the try catch clause may be omitted.
+  /// try {
+  ///   std::string response = co_await http_request("github.com");
+  /// } (std::exception& e) {
+  ///   e.what();
+  /// }
+  /// ```
+  ///
+  /// In case the library is configured to use error codes or a custom
+  /// exception type the return type of the co_await expression is changed.
+  /// The result is returned through a cti::result<...>.
+  /// |          Continuation type        |          co_await returns          |
+  /// | : ------------------------------- | : -------------------------------- |
+  /// | `continuable_base with <>`        | `result<void>`                     |
+  /// | `continuable_base with <Arg>`     | `result<Arg>`                      |
+  /// | `continuable_base with <Args...>` | `result<Args...>`                  |
+  ///
+  /// \note  Using continuable_base as return type for coroutines
+  ///        is supported. The coroutine is initially stopped and
+  ///        resumed when the continuation is requested in order to
+  ///        keep the lazy evaluation semantics of the continuable_base.
+  /// ```cpp
+  /// cti::continuable<> resolve_async_void() {
+  ///   co_await http_request("github.com");
+  ///   // ...
+  ///   co_return;
+  /// }
+  ///
+  /// cti::continuable<int> resolve_async() {
+  ///   co_await http_request("github.com");
+  ///   // ...
+  ///   co_return 0;
+  /// }
+  /// ```
+  /// It's possible to return multiple return values from coroutines
+  /// by wrapping those in a tuple like type:
+  /// ```cpp
+  /// cti::continuable<int, int, int> resolve_async_multiple() {
+  ///   co_await http_request("github.com");
+  ///   // ...
+  ///   co_return std::make_tuple(0, 1, 2);
+  /// }
+  /// ```
+  ///
+  /// \since     2.0.0
   auto operator co_await() && {
-    return detail::awaiting::create_awaiter(std::move(*this).materialize());
+    return detail::awaiting::create_awaiter(std::move(*this).finish());
   }
-#endif // CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE
+  /// \cond false
+#endif // defined(CONTINUABLE_HAS_COROUTINE)
+  /// \endcond
 
 private:
   void release() noexcept {
     ownership_.release();
   }
 
-  auto materialize() && {
+  Data&& consume() && {
-    return detail::composition::materializer<continuable_base>::apply(
-        std::move(*this));
-  }
-
-  Data&& consume_data() && {
     assert_acquired();
     release();
     return std::move(data_);
@@ -636,20 +799,20 @@ private:
   }
 };
 
-/// Creates a continuable_base from a callback taking function.
+/// Creates a continuable_base from a promise/callback taking function.
 ///
-/// \tparam Args The types (signature hint) the given callback is called with.
+/// \tparam Args The types (signature hint) the given promise is resolved with.
-/// * **Some arguments** indicate the types the callback will be invoked with.
+/// * **Some arguments** indicate the types the promise will be invoked with.
 /// ```cpp
-/// auto ct = cti::make_continuable<int, std::string>([](auto&& callback) {
+/// auto ct = cti::make_continuable<int, std::string>([](auto&& promise) {
-///   std::forward<decltype(callback)>(callback)(200, "<html>...</html>");
+///   promise.set_value(200, "<html>...</html>");
 /// });
 /// ```
-/// * **void as argument** indicates that the callback will be invoked
+/// * `void` **as argument** indicates that the promise will be invoked
 ///   with no arguments:
 /// ```cpp
-/// auto ct = cti::make_continuable<void>([](auto&& callback) {
+/// auto ct = cti::make_continuable<void>([](auto&& promise) {
-///   std::forward<decltype(callback)>(callback)();
+///   promise.set_value();
 /// });
 /// ```
 /// * **No arguments** Since version 3.0.0 make_continuable always requires
@@ -660,13 +823,13 @@ private:
 ///   the continuable right after creation.
 /// ```cpp
 /// // This won't work because the arguments are missing:
-/// auto ct = cti::make_continuable([](auto&& callback) {
+/// auto ct = cti::make_continuable([](auto&& promise) {
-///   std::forward<decltype(callback)>(callback)(0.f, 'c');
+///   promise.set_value(0.f, 'c');
 /// });
 ///
 /// // However, you are allowed to do this:
-/// continuable<float, char> ct = [](auto&& callback) {
+/// cti::continuable<float, char> ct = [](auto&& promise) {
-///   std::forward<decltype(callback)>(callback)(0.f, 'c');
+///   promise.set_value(callback)(0.f, 'c');
 /// };
 /// ```
 ///
@@ -706,94 +869,273 @@ private:
 ///   });
 /// ```
 ///
-/// \returns A continuable_base with unknown template parameters which
+/// \returns A continuable_base with unspecified template parameters which
 ///          wraps the given continuation.
 ///          In order to convert the continuable_base to a known type
-///          you need to apply type erasure.
+///          you need to apply type erasure through the
+///          \link cti::continuable continuable\endlink or
+///          \link cti::promise promise\endlink facilities.
 ///
-/// \note You should always turn the callback into a r-value if possible
+/// \note You should always turn the callback/promise into a r-value if possible
 ///       (`std::move` or `std::forward`) for qualifier correct invokation.
+///       Additionally it's important to know that all continuable promises
+///       are callbacks and just expose their call operator nicely through
+///       \link cti::promise_base::set_value set_value \endlink and
+///       \link cti::promise_base::set_exception set_exception \endlink.
 ///
 /// \since 1.0.0
 template <typename... Args, typename Continuation>
-auto make_continuable(Continuation&& continuation) {
+constexpr auto make_continuable(Continuation&& continuation) {
   static_assert(sizeof...(Args) > 0,
                 "Since version 3.0.0 make_continuable requires an exact "
                 "signature! If you did intend to create a void continuable "
                 "use make_continuable<void>(...). Continuables with an exact "
                 "signature may be created through make_continuable<Args...>.");
 
-  return detail::base::attorney::create(
+  return detail::base::attorney::create_from(
       std::forward<Continuation>(continuation),
-      detail::hints::extract(detail::traits::identity<Args...>{}),
+      typename detail::hints::from_args<Args...>::type{},
       detail::util::ownership{});
 }
 
-/// Returns a continuable with no result which instantly resolves
+/// Returns a continuable_base with no result which instantly resolves
 /// the promise with no values.
 ///
 /// \attention Usually using this function isn't needed at all since
 ///            the continuable library is capable of working with
 ///            plain values in most cases.
-///            Try not to use it since it causes unneccessary recursive
+///            Try not to use it since it causes unnecessary recursive
 ///            function calls.
 ///
 /// \since     3.0.0
 template <typename... Args>
-constexpr auto make_ready_continuable() {
+auto make_ready_continuable(Args&&... args) {
-  return make_continuable<void>([](auto&& promise) {
+  return detail::base::attorney::create_from_raw(
-    std::forward<decltype(promise)>(promise).set_value();
+      detail::base::ready_continuation<detail::traits::unrefcv_t<Args>...>(
-  });
+          result<detail::traits::unrefcv_t<Args>...>::from(
+              std::forward<Args>(args)...)),
+      detail::identity<detail::traits::unrefcv_t<Args>...>{},
+      detail::util::ownership{});
 }
 
-/// Returns a continuable with one result value which instantly resolves
+/// Returns a continuable_base with the parameterized result which instantly
-/// the promise with the given value.
-///
-/// \copydetails make_ready_continuable()
-template <typename Result>
-constexpr auto make_ready_continuable(Result&& result) {
-  return make_continuable<std::decay_t<Result>>( // ...
-      [result = std::forward<Result>(result)](auto&& promise) mutable {
-        std::forward<decltype(promise)>(promise).set_value(std::move(result));
-      });
-}
-
-/// Returns a continuable with multiple result values which instantly resolves
-/// the promise with the given values.
-///
-/// \copydetails make_ready_continuable()
-template <typename FirstResult, typename SecondResult, typename... Rest>
-constexpr auto make_ready_continuable(FirstResult&& first_result,
-                                      SecondResult&& second_result,
-                                      Rest&&... rest) {
-  return make_continuable<std::decay_t<FirstResult>, std::decay_t<SecondResult>,
-                          std::decay_t<Rest>...>( // ...
-      [result = std::make_tuple(std::forward<FirstResult>(first_result),
-                                std::forward<SecondResult>(second_result),
-                                std::forward<Rest>(rest)...)](
-          auto&& promise) mutable {
-        detail::traits::unpack(result,
-                               std::forward<decltype(promise)>(promise));
-      });
-}
-
-/// Returns a continuable with the parameterized result which instantly
 /// resolves the promise with the given error type.
 ///
+/// See an example below:
+/// ```cpp
+/// std::logic_error exception("Some issue!");
+/// auto ptr = std::make_exception_ptr(exception);
+/// auto ct = cti::make_exceptional_continuable<int>(ptr);
+/// ```
+///
+/// \tparam Args The fake signature of the returned continuable.
+///
+/// \since            3.0.0
+template <typename... Args, typename Exception>
+constexpr auto make_exceptional_continuable(Exception&& exception) {
+  static_assert(sizeof...(Args) > 0,
+                "Requires at least one type for the fake signature!");
+
+  using hint_t = typename detail::hints::from_args<Args...>::type;
+  using ready_continuation_t = typename detail::base::
+      ready_continuation_from_hint<hint_t>::type;
+  using result_t = typename detail::base::result_from_hint<hint_t>::type;
+  return detail::base::attorney::create_from_raw(
+      ready_continuation_t(result_t::from(exception_arg_t{},
+                                          std::forward<Exception>(exception))),
+      hint_t{}, detail::util::ownership{});
+}
+
+/// Returns a continuable_base with the parameterized result which never
+/// resolves its promise and thus cancels the asynchronous continuation chain
+/// through throwing a default constructed exception_t.
+///
+/// This can be used to cancel an asynchronous continuation chain when
+/// returning a continuable_base from a handler where other paths could
+/// possibly continue the asynchronous chain. See an example below:
+/// ```cpp
+/// do_sth().then([weak = this->weak_from_this()]() -> continuable<> {
+///   if (auto me = weak.lock()) {
+///     return do_sth_more();
+///   } else {
+///     // Abort the asynchronous continuation chain since the
+///     // weakly referenced object expired previously.
+///     return make_cancelling_continuable<void>();
+///   }
+/// });
+/// ```
+/// The default unhandled exception handler ignores exception types
+/// that don't evaluate to true when being converted to a bool.
+/// This saves expensive construction of std::exception_ptr or similar types,
+/// where only one exception type is used for signaling the cancellation.
+///
 /// \tparam Signature The fake signature of the returned continuable.
 ///
-/// \since            3.0.0
+/// \since            4.0.0
-template <typename... Signature, typename Exception>
+template <typename... Signature>
-constexpr auto make_exceptional_continuable(Exception&& exception) {
+auto make_cancelling_continuable() {
   static_assert(sizeof...(Signature) > 0,
                 "Requires at least one type for the fake signature!");
 
-  return make_continuable<Signature...>( // ...
+  return make_exceptional_continuable<Signature...>(exception_t{});
-      [exception = std::forward<Exception>(exception)](auto&& promise) mutable {
-        std::forward<decltype(promise)>(promise).set_exception(
-            std::move(exception));
-      });
 }
+
+/// Can be used to disable the special meaning for a returned value in
+/// asynchronous handler functions.
+///
+/// Several types have a special meaning when being returned from a callable
+/// passed to asynchronous handler functions like:
+/// - continuable_base::then
+/// - continuable_base::fail
+/// - continuable_base::next
+///
+/// For instance such types are std::tuple, std::pair and cti::result.
+///
+/// Wrapping such an object through a call to make_plain disables the special
+/// meaning for such objects as shown below:
+/// ```cpp
+/// continuable<result<int, int> c = http_request("example.com")
+///   .then([](std::string content) {
+///     return make_plain(make_result(0, 1));
+///   })
+/// ```
+///
+/// \since 4.0.0
+///
+template <typename T>
+auto make_plain(T&& value) {
+  return plain_t<detail::traits::unrefcv_t<T>>(std::forward<T>(value));
+}
+
+/// Can be used to recover to from a failure handler,
+/// the result handler which comes after will be called with the
+/// corresponding result.
+///
+/// The \ref exceptional_result returned by this function can be returned
+/// from any result or failure handler in order to rethrow the exception.
+/// ```cpp
+/// http_request("example.com")
+///   .then([](std::string content) {
+///     return recover(1, 2);
+///   })
+///   .fail([](cti::exception_t exception) {
+///     return recover(1, 2);
+///   })
+///   .then([](int a, int b) {
+///     // Recovered from the failure
+///   })
+/// ```
+/// A corresponding \ref result is returned by \ref recover
+/// ```cpp
+/// http_request("example.com")
+///   .then([](std::string content) -> cti::result<int, int> {
+///     return recover(1, 2);
+///   })
+///   .fail([](cti::exception_t exception) -> cti::result<int, int> {
+///     return recover(1, 2);
+///   })
+///   .then([](int a, int b) -> cti::result<int, int> {
+///     // Recovered from the failure
+///   })
+/// ```
+///
+/// \since 4.0.0
+///
+template <typename... Args>
+result<detail::traits::unrefcv_t<Args>...> recover(Args&&... args) {
+  return make_result(std::forward<Args>(args)...);
+}
+
+/// Can be used to rethrow an exception to the asynchronous continuation chain,
+/// the failure handler which comes after will be called with the
+/// corresponding exception.
+///
+/// The \ref exceptional_result returned by this function can be returned
+/// from any result or failure handler in order to rethrow the exception.
+/// ```cpp
+/// http_request("example.com")
+///   .then([](std::string content) {
+///     return rethrow(std::make_exception_ptr(std::exception{}));
+///   })
+///   .fail([](cti::exception_t exception) {
+///     return rethrow(std::make_exception_ptr(std::exception{}));
+///   })
+///   .next([](auto&&...) {
+///     return rethrow(std::make_exception_ptr(std::exception{}));
+///   });
+/// ```
+/// The returned \ref exceptional_result is convertible to
+/// any \ref result as shown below:
+/// ```cpp
+/// http_request("example.com")
+///   .then([](std::string content) -> cti::result<> {
+///     return rethrow(std::make_exception_ptr(std::exception{}));
+///   })
+///   .fail([](cti::exception_t exception) -> cti::result<> {
+///     return rethrow(std::make_exception_ptr(std::exception{}));
+///   })
+///   .next([](auto&&...) -> cti::result<> {
+///     return rethrow(std::make_exception_ptr(std::exception{}));
+///   });
+/// ```
+///
+/// \since 4.0.0
+///
+// NOLINTNEXTLINE(performance-unnecessary-value-param)
+inline exceptional_result rethrow(exception_t exception) {
+  // NOLINTNEXTLINE(hicpp-move-const-arg, performance-move-const-arg)
+  return exceptional_result{std::move(exception)};
+}
+
+/// Can be used to cancel an asynchronous continuation chain,
+/// the next failure handler which comes after cancel will be called
+/// with a default constructed exception_t object.
+///
+/// The \ref cancellation_result returned by this function can be returned from
+/// any result or failure handler in order to cancel the chain.
+/// ```cpp
+/// http_request("example.com")
+///   .then([](std::string content) {
+///     return cancel();
+///   })
+///   .fail([](cti::exception_t exception) {
+///     return cancel();
+///   })
+///   .next([](auto&&...) {
+///     return cancel();
+///   });
+/// ```
+/// The returned \ref empty_result is convertible to
+/// any \ref result as shown below:
+/// ```cpp
+/// http_request("example.com")
+///   .then([](std::string content) -> cti::result<> {
+///     return cancel();
+///   })
+///   .fail([](cti::exception_t exception) -> cti::result<> {
+///     return cancel();
+///   })
+///   .next([](auto&&...) -> cti::result<> {
+///     return cancel();
+///   });
+/// ```
+///
+/// \since 4.0.0
+///
+inline cancellation_result cancel() {
+  return {};
+}
+
+/// Can be used to stop an asynchronous continuation chain,
+/// no handler which comes after stop was received won't be called.
+///
+/// \since 4.0.0
+///
+inline empty_result stop() {
+  return {};
+}
+
+/// \}
 } // namespace cti
 
 #endif // CONTINUABLE_BASE_HPP_INCLUDED

include/continuable/continuable-connections.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,25 +21,32 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_COMPOSITIONS_HPP_INCLUDED
+#ifndef CONTINUABLE_CONNECTIONS_HPP_INCLUDED
-#define CONTINUABLE_COMPOSITIONS_HPP_INCLUDED
+#define CONTINUABLE_CONNECTIONS_HPP_INCLUDED
 
+#include <initializer_list>
+#include <memory>
 #include <utility>
-
+#include <vector>
-#include <continuable/detail/composition-all.hpp>
+#include <continuable/detail/connection/connection-all.hpp>
-#include <continuable/detail/composition-any.hpp>
+#include <continuable/detail/connection/connection-any.hpp>
-#include <continuable/detail/composition-seq.hpp>
+#include <continuable/detail/connection/connection-seq.hpp>
-#include <continuable/detail/composition.hpp>
+#include <continuable/detail/connection/connection.hpp>
-#include <continuable/detail/range.hpp>
+#include <continuable/detail/traversal/range.hpp>
 
 namespace cti {
+/// \defgroup Connections Connections
+/// provides functions to connect \link continuable_base
+/// continuable_bases\endlink through various strategies.
+/// \{
+
 /// Connects the given arguments with an all logic.
 /// All continuables contained inside the given nested pack are
 /// invoked at once. On completion the final handler is called
@@ -55,8 +62,8 @@ namespace cti {
 /// cti::when_all(
 ///     cti::make_ready_continuable(0, 1),
 ///     2, //< See this plain value
-///     std::vector<cti::continuable<int>>{cti::make_ready_continuable(3),
+///     cti::populate(cti::make_ready_continuable(3),  // Creates a runtime
-///                                        cti::make_ready_continuable(4)},
+///                   cti::make_ready_continuable(4)), // sized container.
 ///     std::make_tuple(std::make_tuple(cti::make_ready_continuable(5))))
 ///       .then([](int r0, int r1, int r2, std::vector<int> r34,
 ///                std::tuple<std::tuple<int>> r5) {
@@ -69,8 +76,8 @@ namespace cti {
 /// \since      1.1.0
 template <typename... Args>
 auto when_all(Args&&... args) {
-  return detail::composition::apply_composition(
+  return detail::connection::apply_connection(
-      detail::composition::composition_strategy_all_tag{},
+      detail::connection::connection_strategy_all_tag{},
       std::forward<Args>(args)...);
 }
 
@@ -79,8 +86,9 @@ auto when_all(Args&&... args) {
 /// to a temporary `std::vector` which is then passed to when_all.
 ///
 /// ```cpp
-/// std::vector<cti::continuable<int>> v{cti::make_ready_continuable(0),
+/// // cti::populate just creates a std::vector from the two continuables.
-///                                      cti::make_ready_continuable(1)};
+/// auto v = cti::populate(cti::make_ready_continuable(0),
+///                        cti::make_ready_continuable(1));
 ///
 /// cti::when_all(v.begin(), v.end())
 ///   .then([](std::vector<int> r01) {
@@ -123,8 +131,8 @@ auto when_all(Iterator begin, Iterator end) {
 /// cti::when_seq(
 ///     cti::make_ready_continuable(0, 1),
 ///     2, //< See this plain value
-///     std::vector<cti::continuable<int>>{cti::make_ready_continuable(3),
+///     cti::populate(cti::make_ready_continuable(3),  // Creates a runtime
-///                                        cti::make_ready_continuable(4)},
+///                   cti::make_ready_continuable(4)), // sized container.
 ///     std::make_tuple(std::make_tuple(cti::make_ready_continuable(5))))
 ///       .then([](int r0, int r1, int r2, std::vector<int> r34,
 ///                std::tuple<std::tuple<int>> r5) {
@@ -137,8 +145,8 @@ auto when_all(Iterator begin, Iterator end) {
 /// \since      1.1.0
 template <typename... Args>
 auto when_seq(Args&&... args) {
-  return detail::composition::apply_composition(
+  return detail::connection::apply_connection(
-      detail::composition::composition_strategy_seq_tag{},
+      detail::connection::connection_strategy_seq_tag{},
       std::forward<Args>(args)...);
 }
 
@@ -147,8 +155,9 @@ auto when_seq(Args&&... args) {
 /// to a temporary `std::vector` which is then passed to when_seq.
 ///
 /// ```cpp
-/// std::vector<cti::continuable<int>> v{cti::make_ready_continuable(0),
+/// // cti::populate just creates a std::vector from the two continuables.
-///                                      cti::make_ready_continuable(1)};
+/// auto v = cti::populate(cti::make_ready_continuable(0),
+///                        cti::make_ready_continuable(1));
 ///
 /// cti::when_seq(v.begin(), v.end())
 ///   .then([](std::vector<int> r01) {
@@ -191,8 +200,8 @@ auto when_seq(Iterator begin, Iterator end) {
 /// cti::when_any(
 ///     cti::make_ready_continuable(0, 1),
 ///     2, //< See this plain value
-///     std::vector<cti::continuable<int>>{cti::make_ready_continuable(3),
+///     cti::populate(cti::make_ready_continuable(3),  // Creates a runtime
-///                                        cti::make_ready_continuable(4)},
+///                   cti::make_ready_continuable(4)), // sized container.
 ///     std::make_tuple(std::make_tuple(cti::make_ready_continuable(5))))
 ///       .then([](int r0) {
 ///         // ...
@@ -204,8 +213,8 @@ auto when_seq(Iterator begin, Iterator end) {
 /// \since      1.1.0
 template <typename... Args>
 auto when_any(Args&&... args) {
-  return detail::composition::apply_composition(
+  return detail::connection::apply_connection(
-      detail::composition::composition_strategy_any_tag{},
+      detail::connection::connection_strategy_any_tag{},
       std::forward<Args>(args)...);
 }
 
@@ -214,8 +223,9 @@ auto when_any(Args&&... args) {
 /// to a temporary `std::vector` which is then passed to when_all.
 ///
 /// ```cpp
-/// std::vector<cti::continuable<int>> v{cti::make_ready_continuable(0),
+/// // cti::populate just creates a std::vector from the two continuables.
-///                                      cti::make_ready_continuable(1)};
+/// auto v = cti::populate(cti::make_ready_continuable(0),
+///                        cti::make_ready_continuable(1));
 ///
 /// cti::when_any(v.begin(), v.end())
 ///   .then([](int r01) {
@@ -242,6 +252,50 @@ template <
 auto when_any(Iterator begin, Iterator end) {
   return when_any(detail::range::persist_range(begin, end));
 }
+
+/// Populates a homogeneous container from the given arguments.
+/// All arguments need to be convertible to the first one,
+/// by default `std::vector` is used as container type.
+///
+/// This method mainly helps to create a homogeneous container from
+/// a runtime known count of continuables which type isn't exactly known.
+/// All continuables which are passed to this function should be originating
+/// from the same source or a method called with the same types of arguments:
+/// ```cpp
+/// auto container = cti::populate(cti::make_ready_continuable(0),
+///                                cti::make_ready_continuable(1)),
+///
+/// for (int i = 2; i < 5; ++i) {
+///   // You may add more continuables to the container afterwards
+///   container.emplace_back(cti::make_ready_continuable(i));
+/// }
+///
+/// cti::when_any(std::move(container))
+///   .then([](int) {
+///     // ...
+///   });
+/// ```
+/// Additionally it is possible to change the targeted container as below:
+/// ```cpp
+/// auto container = cti::populate<std::list>(cti::make_ready_continuable(0),
+///                                           cti::make_ready_continuable(1)),
+/// ```
+///
+/// \tparam C The container type which is used to store the arguments into.
+///
+/// \since    3.0.0
+template <template <typename, typename> class C = std::vector, typename First,
+          typename... Args>
+C<std::decay_t<First>, std::allocator<std::decay_t<First>>>
+populate(First&& first, Args&&... args) {
+  C<std::decay_t<First>, std::allocator<std::decay_t<First>>> container;
+  container.reserve(1 + sizeof...(Args));
+  container.emplace_back(std::forward<First>(first));
+  (void)std::initializer_list<int>{
+      0, ((void)container.emplace_back(std::forward<Args>(args)), 0)...};
+  return container; // RVO
+}
+/// \}
 } // namespace cti
 
-#endif // CONTINUABLE_COMPOSITIONS_HPP_INCLUDED
+#endif // CONTINUABLE_CONNECTIONS_HPP_INCLUDED

include/continuable/continuable-coroutine.hpp

@@ -0,0 +1,97 @@
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_COROUTINE_HPP_INCLUDED
+#define CONTINUABLE_COROUTINE_HPP_INCLUDED
+
+#include <continuable/continuable-base.hpp>
+#include <continuable/continuable-types.hpp>
+#include <continuable/detail/core/types.hpp>
+#include <continuable/detail/features.hpp>
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#  include <exception>
+#endif // CONTINUABLE_HAS_EXCEPTIONS
+
+#if defined(CONTINUABLE_HAS_COROUTINE)
+#  include <continuable/detail/other/coroutines.hpp>
+
+namespace cti {
+#  if defined(CONTINUABLE_HAS_EXCEPTIONS)
+/// Is thrown from co_await expressions if the awaited continuable is canceled
+///
+/// Default constructed exception types that are returned by a cancelled
+/// continuable are converted automatically to await_canceled_exception when
+/// being returned by a co_await expression.
+///
+/// The await_canceled_exception gets converted again to a default constructed
+/// exception type if it becomes unhandled inside a coroutine which
+/// returns a continuable_base.
+/// ```cpp
+/// continuable<> cancelled_coroutine() {
+///   co_await make_cancelling_continuable<void>();
+///
+///   co_return;
+/// }
+///
+/// // ...
+///
+/// cancelled_coroutine().fail([](exception_t e) {
+///   assert(bool(e) == false);
+/// });
+/// ```
+///
+/// \since 4.1.0
+using await_canceled_exception = detail::awaiting::await_canceled_exception;
+#  endif // CONTINUABLE_HAS_EXCEPTIONS
+} // namespace cti
+
+/// \cond false
+// As far as I know there is no other way to implement this specialization...
+// NOLINTNEXTLINE(cert-dcl58-cpp)
+namespace std {
+#  if defined(CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
+namespace experimental {
+#  endif // defined(CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
+template <typename Data, typename... Args, typename... FunctionArgs>
+struct coroutine_traits<
+    cti::continuable_base<Data, cti::detail::identity<Args...>>,
+    FunctionArgs...> {
+
+  using promise_type = cti::detail::awaiting::promise_type<
+      cti::continuable<Args...>, cti::promise<Args...>, Args...>;
+};
+#  if defined(CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
+} // namespace experimental
+#  endif // defined(CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
+} // namespace std
+  /// \endcond
+#endif // defined(CONTINUABLE_HAS_COROUTINE)
+
+#endif // CONTINUABLE_COROUTINE_HPP_INCLUDED

include/continuable/continuable-operations.hpp

@@ -0,0 +1,41 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_OPERATIONS_HPP_INCLUDED
+#define CONTINUABLE_OPERATIONS_HPP_INCLUDED
+
+/// \defgroup Operations Operations
+/// provides functions to work with asynchronous control flows.
+
+#include <continuable/operations/async.hpp>
+#include <continuable/operations/loop.hpp>
+#include <continuable/operations/split.hpp>
+
+#endif // CONTINUABLE_OPERATIONS_HPP_INCLUDED

include/continuable/continuable-primitives.hpp

@@ -0,0 +1,141 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_PRIMITIVES_HPP_INCLUDED
+#define CONTINUABLE_PRIMITIVES_HPP_INCLUDED
+
+#include <continuable/detail/core/types.hpp>
+#include <continuable/detail/utility/identity.hpp>
+
+namespace cti {
+/// \defgroup Primitives Primitives
+/// provides basic tag types for creating a customized callbacks
+/// and continuations.
+///
+/// For the callback and the continuation `Args...` represents the
+/// asynchronous result:
+/// ```cpp
+/// template<typename... Args>
+/// struct continuation {
+///   void operator() (callback<Args...>);
+///   bool operator() (cti::is_ready_arg_t) const;
+///   result<Args...> operator() (cti::unpack_arg_t);
+/// };
+/// ```
+/// ```cpp
+/// template<typename... Args>
+/// struct callback {
+///   void operator() (Args...) &&;
+///   void operator() (cti::exception_arg_t, cti::exception_t) &&;
+/// };
+/// ```
+/// \{
+
+/// Represents the tag type that is used to specify the signature hint
+/// of a continuable_base or promise_base.
+///
+/// \since 4.0.0
+template <typename... Args>
+using signature_arg_t = detail::identity<Args...>;
+
+/// Represents the tag type that is used to query the continuation
+/// for whether it resolves the callback instantly with its arguments
+/// without having side effects.
+///
+/// \since 4.0.0
+struct is_ready_arg_t {};
+
+/// Represents the tag type that is used to unpack the result of a continuation.
+///
+/// \attention It's required that the query of is_ready_arg_t returns true,
+///            otherwise the behaviour when unpacking is unspecified.
+///
+/// \since 4.0.0
+struct unpack_arg_t {};
+
+/// \copydoc unpack_arg_t
+///
+/// \deprecated The query_arg_t was deprecated because of
+///             its new naming unpack_arg_t.
+///
+[[deprecated("The dispatch_error_tag was replaced by unpack_arg_t and will "
+             "be removed in a later major version!")]] //
+    typedef unpack_arg_t query_arg_t;
+
+/// Represents the tag type that is used to disambiguate the
+/// callback operator() in order to take the exception asynchronous chain.
+///
+/// \note see continuable::next for details.
+///
+/// \since 4.0.0
+struct exception_arg_t {};
+
+/// \copydoc exception_arg_t
+///
+/// \deprecated The dispatch_error_tag was deprecated in order to move closer
+///             to the types specified in the "A Unified Future" proposal
+///             especially regarding naming types similar.
+///
+[[deprecated("The dispatch_error_tag was replaced by exception_arg_t and will "
+             "be removed in a later major version!")]] //
+    typedef exception_arg_t dispatch_error_tag;
+
+/// Represents the type that is used as exception type
+///
+/// By default this type deduces to `std::exception_ptr`.
+/// If `CONTINUABLE_WITH_NO_EXCEPTIONS` is defined the type
+/// will be a `std::error_condition`.
+/// A custom error type may be set through
+/// defining `CONTINUABLE_WITH_CUSTOM_ERROR_TYPE`.
+///
+/// \since 4.0.0
+using exception_t = detail::types::exception_t;
+
+/// \copydoc exception_t
+///
+/// \deprecated The error_type was deprecated in order to move closer
+///             to the types specified in the "A Unified Future" proposal
+///             especially regarding naming types similar.
+///
+[[deprecated("The error_type was replaced by exception_t and will "
+             "be removed in a later major version!")]] //
+    typedef exception_t error_type;
+
+/// Represents the type that is used to disable the special meaning of types
+/// which are returned by a asynchronous result handler.
+/// See cti::plain for details.
+///
+/// \since 4.0.0
+template <typename T>
+using plain_t = detail::types::plain_tag<T>;
+/// \}
+} // namespace cti
+
+#endif // CONTINUABLE_PRIMITIVES_HPP_INCLUDED

include/continuable/continuable-promise-base.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -31,20 +31,32 @@
 #ifndef CONTINUABLE_PROMISE_BASE_HPP_INCLUDED
 #define CONTINUABLE_PROMISE_BASE_HPP_INCLUDED
 
+#include <cassert>
 #include <type_traits>
 #include <utility>
-
+#include <continuable/continuable-primitives.hpp>
-#include <continuable/detail/hints.hpp>
+#include <continuable/detail/core/annotation.hpp>
-#include <continuable/detail/types.hpp>
+#include <continuable/detail/core/types.hpp>
-#include <continuable/detail/util.hpp>
+#include <continuable/detail/utility/traits.hpp>
+#include <continuable/detail/utility/util.hpp>
 
 namespace cti {
+/// \defgroup Base Base
+/// provides classes and functions to create continuable_base objects.
+/// \{
+
 /// The promise_base makes it possible to resolve an asynchronous
 /// continuable through it's result or through an error type.
 ///
 /// Use the promise type defined in `continuable/continuable_types.hpp`,
 /// in order to use this class.
 ///
+/// If we want to resolve the  promise_base trough the call operator,
+/// and we want to resolve it through an exception, we must call it with a
+/// exception_arg_t as first and the exception as second argument.
+/// Additionally the promise is resolveable only through its call
+/// operator when invoked as an r-value.
+///
 /// \since 2.0.0
 // clang-format off
 template <typename Data, typename Hint>
@@ -52,7 +64,7 @@ class promise_base
   /// \cond false
   ;
 template <typename Data, typename... Args>
-class promise_base<Data, detail::hints::signature_hint_tag<Args...>>
+class promise_base<Data, detail::identity<Args...>>
     : detail::util::non_copyable
   /// \endcond
 { // clang-format on
@@ -63,53 +75,141 @@ class promise_base<Data, detail::hints::signature_hint_tag<Args...>>
   /// \endcond
 
 public:
+  /// Constructor for constructing an empty promise
+  explicit promise_base() = default;
   /// Constructor accepting the data object
   explicit promise_base(Data data) : data_(std::move(data)) {
   }
 
+  /// \cond false
+  promise_base(promise_base&&) = default;
+  promise_base(promise_base const&) = delete;
+
+  promise_base& operator=(promise_base&&) = default;
+  promise_base& operator=(promise_base const&) = delete;
+  /// \endcond
+
   /// Constructor accepting any object convertible to the data object
-  template <typename OData, std::enable_if_t<std::is_convertible<
+  template <typename OData,
-                                std::decay_t<OData>, Data>::value>* = nullptr>
+            std::enable_if_t<std::is_convertible<
-  promise_base(OData&& data) : data_(std::forward<OData>(data)) {
+                detail::traits::unrefcv_t<OData>, Data>::value>* = nullptr>
+  /* implicit */ promise_base(OData&& data) : data_(std::forward<OData>(data)) {
+  }
+
+  /// Assignment operator accepting any object convertible to the data object
+  template <typename OData,
+            std::enable_if_t<std::is_convertible<
+                detail::traits::unrefcv_t<OData>, Data>::value>* = nullptr>
+  promise_base& operator=(OData&& data) {
+    data_ = std::forward<OData>(data);
+    return *this;
   }
 
   /// Resolves the continuation with the given values.
   ///
   /// \throws This method never throws an exception.
   ///
+  /// \attention This method may only be called once,
+  ///            when the promise is valid operator bool() returns true.
+  ///            Calling this method will invalidate the promise such that
+  ///            subsequent calls to operator bool() will return false.
+  ///            This behaviour is only consistent in promise_base and
+  ///            non type erased promises may behave differently.
+  ///            Invoking an invalid promise_base is undefined!
+  ///
   /// \since  2.0.0
   void operator()(Args... args) && noexcept {
+    assert(data_);
     std::move(data_)(std::move(args)...);
+    data_ = nullptr;
   }
   /// Resolves the continuation with the given exception.
   ///
   /// \throws This method never throws an exception.
   ///
+  /// \attention This method may only be called once,
+  ///            when the promise is valid operator bool() returns true.
+  ///            Calling this method will invalidate the promise such that
+  ///            subsequent calls to operator bool() will return false.
+  ///            This behaviour is only consistent in promise_base and
+  ///            non type erased promises may behave differently.
+  ///            Invoking an invalid promise_base is undefined!
+  ///
   /// \since  2.0.0
-  void operator()(detail::types::dispatch_error_tag tag,
+  void operator()(exception_arg_t tag, exception_t exception) && noexcept {
-                  detail::types::error_type exception) &&
+    assert(data_);
-      noexcept {
     std::move(data_)(tag, std::move(exception));
+    data_ = nullptr;
   }
 
   /// Resolves the continuation with the given values.
   ///
   /// \throws This method never throws an exception.
   ///
+  /// \attention This method may only be called once,
+  ///            when the promise is valid operator bool() returns true.
+  ///            Calling this method will invalidate the promise such that
+  ///            subsequent calls to operator bool() will return false.
+  ///            This behaviour is only consistent in promise_base and
+  ///            non type erased promises may behave differently.
+  ///            Invoking an invalid promise_base is undefined!
+  ///
   /// \since  2.0.0
   void set_value(Args... args) noexcept {
+    // assert(data_);
     std::move(data_)(std::move(args)...);
+    data_ = nullptr;
   }
 
   /// Resolves the continuation with the given exception.
   ///
   /// \throws This method never throws an exception.
   ///
+  /// \attention This method may only be called once,
+  ///            when the promise is valid operator bool() returns true.
+  ///            Calling this method will invalidate the promise such that
+  ///            subsequent calls to operator bool() will return false.
+  ///            This behaviour is only consistent in promise_base and
+  ///            non type erased promises may behave differently.
+  ///            Invoking an invalid promise_base is undefined!
+  ///
   /// \since  2.0.0
-  void set_exception(detail::types::error_type exception) noexcept {
+  void set_exception(exception_t exception) noexcept {
-    std::move(data_)(detail::types::dispatch_error_tag{}, std::move(exception));
+    assert(data_);
+    std::move(data_)(exception_arg_t{}, std::move(exception));
+    data_ = nullptr;
+  }
+
+  /// Resolves the continuation with the cancellation token which is represented
+  /// by a default constructed exception_t.
+  ///
+  /// \throws This method never throws an exception.
+  ///
+  /// \attention This method may only be called once,
+  ///            when the promise is valid operator bool() returns true.
+  ///            Calling this method will invalidate the promise such that
+  ///            subsequent calls to operator bool() will return false.
+  ///            This behaviour is only consistent in promise_base and
+  ///            non type erased promises may behave differently.
+  ///            Invoking an invalid promise_base is undefined!
+  ///
+  /// \since  4.0.0
+  void set_canceled() noexcept {
+    assert(data_);
+    std::move(data_)(exception_arg_t{}, exception_t{});
+    data_ = nullptr;
+  }
+
+  /// Returns true if the continuation is valid (non empty).
+  ///
+  /// \throws This method never throws an exception.
+  ///
+  /// \since  4.0.0
+  explicit operator bool() const noexcept {
+    return bool(data_);
   }
 };
+/// \}
 } // namespace cti
 
 #endif // CONTINUABLE_PROMISE_BASE_HPP_INCLUDED

include/continuable/continuable-promisify.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -33,15 +33,19 @@
 
 #include <type_traits>
 #include <utility>
-
+#include <continuable/detail/other/promisify.hpp>
-#include <continuable/detail/promisify.hpp>
 
 namespace cti {
+/// \defgroup Promisify Promisify
+/// provides helper methods to convert various callback styles to
+/// \link continuable_base continuable_bases\endlink.
+/// \{
+
 /// Helper class for converting callback taking callable types into a
 /// a continuable. Various styles are supported.
-/// - `from_asio`: Converts callback taking callable types into continuables
+/// - `from`: Converts callback taking callable types into continuables
-///                which pass an error code as first parameter and the rest of
+///           which pass an error code as first parameter and the rest of
-///                the result afterwards.
+///           the result afterwards.
 ///
 /// \tparam Result The result of the converted continuable, this should align
 ///                with the arguments that are passed to the callback.
@@ -59,7 +63,7 @@ public:
   /// See an example of how to promisify boost asio's async_resolve below:
   /// ```cpp
   /// auto async_resolve(std::string host, std::string service) {
-  ///   return cti::promisify<asio::ip::udp::resolver::iterator>::from_asio(
+  ///   return cti::promisify<asio::ip::udp::resolver::iterator>::from(
   ///       [&](auto&&... args) {
   ///         resolver_.async_resolve(std::forward<decltype(args)>(args)...);
   ///       },
@@ -67,20 +71,50 @@ public:
   /// }
   /// ```
   ///
-  /// If the error code which is passed as first parameter is set there are
+  /// A given error variable is converted to the used error type.
-  /// two behaviours depending whether exceptions are enabled:
+  /// If this isn't possible you need to create a custom resolver callable
-  /// - If exceptions are enabled the error type is passed via
+  /// object \see with for details.
-  ///   an exception_ptr to the failure handler.
-  /// - If exceptions are disabled the error type is converted to a
-  ///   `std::error_conditon` and passed down to the error handler.
   ///
   /// \since  3.0.0
   template <typename Callable, typename... Args>
-  static auto from_asio(Callable&& callable, Args&&... args) {
+  static auto from(Callable&& callable, Args&&... args) {
-    return helper::template from<detail::convert::promisify_asio>(
+    return helper::template from(detail::convert::default_resolver(),
-        std::forward<Callable>(callable), std::forward<Args>(args)...);
+                                 std::forward<Callable>(callable),
+                                 std::forward<Args>(args)...);
+  }
+
+  /// \copybrief from
+  ///
+  /// This modification of \ref from additionally takes a resolver callable
+  /// object which is used to resolve the promise from the given result.
+  ///
+  /// See an example of how to promisify boost asio's async_resolve below:
+  /// ```cpp
+  /// auto async_resolve(std::string host, std::string service) {
+  ///   return cti::promisify<asio::ip::udp::resolver::iterator>::with(
+  ///       [](auto&& promise, auto&& e, auto&&... args) {
+  ///         if (e) {
+  ///           promise.set_exception(std::forward<decltype(e)>(e));
+  ///         } else {
+  ///           promise.set_value(std::forward<decltype(args)>(args)...);
+  ///         }
+  ///       },
+  ///       [&](auto&&... args) {
+  ///         resolver_.async_resolve(std::forward<decltype(args)>(args)...);
+  ///       },
+  ///       std::move(host), std::move(service));
+  /// }
+  /// ```
+  ///
+  /// \since 4.0.0
+  template <typename Resolver, typename Callable, typename... Args>
+  static auto with(Resolver&& resolver, Callable&& callable, Args&&... args) {
+    return helper::template from(std::forward<Resolver>(resolver),
+                                 std::forward<Callable>(callable),
+                                 std::forward<Args>(args)...);
   }
 };
+/// \}
 } // namespace cti
 
 #endif // CONTINUABLE_PROMISIFY_HPP_INCLUDED

include/continuable/continuable-result.hpp

@@ -0,0 +1,356 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_RESULT_HPP_INCLUDED
+#define CONTINUABLE_RESULT_HPP_INCLUDED
+
+#include <type_traits>
+#include <utility>
+#include <continuable/continuable-primitives.hpp>
+#include <continuable/detail/utility/result-trait.hpp>
+#include <continuable/detail/utility/result-variant.hpp>
+#include <continuable/detail/utility/traits.hpp>
+#include <continuable/detail/utility/util.hpp>
+
+namespace cti {
+/// \defgroup Result Result
+/// provides the \ref result class and corresponding utility functions to work
+/// with the result of an asynchronous operation which can possibly yield:
+/// - *no result*: If the operation didn't finish
+/// - *a value*: If the operation finished successfully
+/// - *an exception*: If the operation finished with an exception
+///                   or was cancelled.
+/// \{
+
+/// A tag which represents present void values in result.
+///
+/// \since 4.0.0
+using void_arg_t = detail::void_arg_t;
+
+/// A class which is convertible to any \ref result and that definitely holds no
+/// value so the real result gets invalidated when this object is passed to it.
+///
+/// \since 4.0.0
+///
+struct empty_result {};
+
+/// A class which is convertible to any \ref result and that definitely holds
+/// a default constructed exception which signals the cancellation of the
+/// asynchronous control flow.
+///
+/// \since 4.0.0
+///
+struct cancellation_result {};
+
+/// A class which is convertible to any result and that holds
+/// an exception which is then passed to the converted result object.
+///
+/// \since 4.0.0
+///
+class exceptional_result {
+  exception_t exception_;
+
+public:
+  exceptional_result() = delete;
+  exceptional_result(exceptional_result const&) = default;
+  exceptional_result(exceptional_result&&) = default;
+  exceptional_result& operator=(exceptional_result const&) = default;
+  exceptional_result& operator=(exceptional_result&&) = default;
+  ~exceptional_result() = default;
+
+  explicit exceptional_result(exception_t exception)
+    // NOLINTNEXTLINE(hicpp-move-const-arg, performance-move-const-arg)
+    : exception_(std::move(exception)) {}
+
+  exceptional_result& operator=(exception_t exception) {
+    // NOLINTNEXTLINE(hicpp-move-const-arg, performance-move-const-arg)
+    exception_ = std::move(exception);
+    return *this;
+  }
+
+  /// Sets an exception
+  void set_exception(exception_t exception) {
+    // NOLINTNEXTLINE(hicpp-move-const-arg, performance-move-const-arg)
+    exception_ = std::move(exception);
+  }
+
+  /// Returns the contained exception
+  exception_t& get_exception() & noexcept {
+    return exception_;
+  }
+  /// \copydoc get_exception
+  exception_t const& get_exception() const& noexcept {
+    return exception_;
+  }
+  /// \copydoc get_exception
+  exception_t&& get_exception() && noexcept {
+    return std::move(exception_);
+  }
+};
+
+/// The result class can carry the three kinds of results an asynchronous
+/// operation possibly can return, it's implemented in a variant like
+/// data structure which is also specialized to hold arbitrary arguments.
+///
+/// The result can be in the following three states:
+/// - *no result*: If the operation didn't finish
+/// - *a value*: If the operation finished successfully
+/// - *an exception*: If the operation finished with an exception
+///                   or was cancelled.
+///
+/// The interface of the result object is similar to the one proposed in
+/// the `std::expected` proposal:
+/// ```cpp
+/// result<std::string> result = make_result("Hello World!");
+/// bool(result);
+/// result.is_value();
+/// result.is_exception();
+/// *result; // Same as result.get_value()
+/// result.get_value();
+/// result.get_exception();
+/// ```
+///
+/// \since 4.0.0
+///
+template <typename... T>
+class result {
+  using trait_t = detail::result_trait<T...>;
+
+  template <typename... Args>
+  explicit result(detail::init_result_arg_t arg, Args&&... values)
+    : variant_(arg, trait_t::wrap(std::forward<Args>(values)...)) {}
+  explicit result(detail::init_exception_arg_t arg, exception_t exception)
+    : variant_(arg, std::move(exception)) {}
+
+public:
+  using value_t = typename trait_t::value_t;
+  using value_placeholder_t = typename trait_t::surrogate_t;
+
+  template <typename FirstArg, typename... Args>
+  explicit result(FirstArg&& first, Args&&... values)
+    : variant_(detail::init_result_arg_t{},
+               trait_t::wrap(std::forward<FirstArg>(first),
+                             std::forward<Args>(values)...)) {}
+
+  result() = default;
+  result(result const&) = delete;
+  result(result&&) = default;
+  result& operator=(result const&) = delete;
+  result& operator=(result&&) = default;
+  ~result() = default;
+
+  explicit result(exception_t exception)
+    : variant_(detail::init_exception_arg_t{}, std::move(exception)) {}
+  /* implicit */ result(empty_result) {}
+  /* implicit */ result(exceptional_result exceptional_result)
+    : variant_(detail::init_exception_arg_t{},
+               std::move(exceptional_result.get_exception())) {}
+  /* implicit */ result(cancellation_result)
+    : variant_(detail::init_exception_arg_t{}, exception_t{}) {}
+
+  result& operator=(empty_result) {
+    variant_.set_empty();
+    return *this;
+  }
+  result& operator=(value_placeholder_t value) {
+    variant_.set_value(std::move(value));
+    return *this;
+  }
+  result& operator=(exceptional_result exception) {
+    variant_.set_exception(std::move(exception.get_exception()));
+    return *this;
+  }
+  result& operator=(cancellation_result) {
+    variant_.set_exception({});
+    return *this;
+  }
+
+  /// Set the result to an empty state
+  void set_empty() {
+    variant_.set_empty();
+  }
+  /// Set the result to a the state which holds the corresponding value
+  void set_value(T... values) {
+    variant_.set_value(trait_t::wrap(std::move(values)...));
+  }
+  /// Set the result into a state which holds the corresponding exception
+  void set_exception(exception_t exception) {
+    variant_.set_exception(std::move(exception));
+  }
+  /// Set the result into a state which holds the cancellation token
+  void set_canceled() {
+    variant_.set_exception(exception_t{});
+  }
+
+  /// Returns true if the state of the result is empty
+  bool is_empty() const noexcept {
+    return variant_.is_empty();
+  }
+  /// Returns true if the state of the result holds the result
+  bool is_value() const noexcept {
+    return variant_.is_value();
+  }
+  /// Returns true if the state of the result holds a present exception
+  bool is_exception() const noexcept {
+    return variant_.is_exception();
+  }
+
+  /// \copydoc is_value
+  explicit constexpr operator bool() const noexcept {
+    return is_value();
+  }
+
+  /// Returns the values of the result, if the result doesn't hold the value
+  /// the behaviour is undefined but will assert in debug mode.
+  decltype(auto) get_value() & noexcept {
+    return trait_t::unwrap(variant_.get_value());
+  }
+  ///\copydoc get_value
+  decltype(auto) get_value() const& noexcept {
+    return trait_t::unwrap(variant_.get_value());
+  }
+  ///\copydoc get_value
+  decltype(auto) get_value() && noexcept {
+    return trait_t::unwrap(std::move(variant_.get_value()));
+  }
+
+  ///\copydoc get_value
+  decltype(auto) operator*() & noexcept {
+    return get_value();
+  }
+  ///\copydoc get_value
+  decltype(auto) operator*() const& noexcept {
+    return get_value();
+  }
+  ///\copydoc get_value
+  decltype(auto) operator*() && noexcept {
+    return std::move(variant_.get_value());
+  }
+
+  /// Returns the exception of the result, if the result doesn't hold an
+  /// exception the behaviour is undefined but will assert in debug mode.
+  exception_t& get_exception() & noexcept {
+    return variant_.get_exception();
+  }
+  /// \copydoc get_exception
+  exception_t const& get_exception() const& noexcept {
+    return variant_.get_exception();
+  }
+  /// \copydoc get_exception
+  exception_t&& get_exception() && noexcept {
+    return std::move(variant_.get_exception());
+  }
+
+  /// Creates a present result from the given values
+  static result from(T... values) {
+    return result{detail::init_result_arg_t{}, std::move(values)...};
+  }
+  /// Creates a present result from the given exception
+  static result from(exception_arg_t, exception_t exception) {
+    return result{detail::init_exception_arg_t{}, std::move(exception)};
+  }
+
+  /// Creates an empty result
+  static result empty() {
+    return result{empty_result{}};
+  }
+
+private:
+  detail::result_variant<value_placeholder_t> variant_;
+};
+
+/// Returns the value at position I of the given result
+template <std::size_t I, typename... T>
+decltype(auto) get(result<T...>& result) {
+  return detail::result_trait<T...>::template get<I>(result);
+}
+/// \copydoc get
+template <std::size_t I, typename... T>
+decltype(auto) get(result<T...> const& result) {
+  return detail::result_trait<T...>::template get<I>(result);
+}
+/// \copydoc get
+template <std::size_t I, typename... T>
+decltype(auto) get(result<T...>&& result) {
+  return detail::result_trait<T...>::template get<I>(std::move(result));
+}
+
+/// Creates a present result from the given values.
+///
+/// This could be used to pass the result of the next handler to the same
+/// asynchronous path it came from as shown below:
+/// ```cpp
+/// make_ready_continuable().next([&](auto&&... args) {
+///   result<> captured = make_result(std::forward<decltype(args)>(args)...);
+///   return shutdown().then([captured = std::move(captured)]() mutable {
+///     return std::move(captured);
+///   });
+/// });
+/// ```
+///
+/// \since 4.0.0
+template <typename... T,
+          typename Result = result<detail::traits::unrefcv_t<T>...>>
+Result make_result(T&&... values) {
+  return Result::from(std::forward<T>(values)...);
+}
+
+/// Creates an exceptional_result from the given exception.
+///
+/// \copydetails make_result
+///
+/// \since 4.0.0
+inline exceptional_result make_result(exception_arg_t, exception_t exception) {
+  // NOLINTNEXTLINE(hicpp-move-const-arg, performance-move-const-arg)
+  return exceptional_result{std::move(exception)};
+}
+/// \}
+} // namespace cti
+
+namespace std {
+// The GCC standard library defines tuple_size as class and struct which
+// triggers a warning here.
+#if defined(__clang__)
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wmismatched-tags"
+#endif
+template <typename... Args>
+struct tuple_size<cti::result<Args...>>
+  : std::integral_constant<size_t, sizeof...(Args)> {};
+
+template <std::size_t I, typename... Args>
+struct tuple_element<I, cti::result<Args...>>
+  : tuple_element<I, tuple<Args...>> {};
+#if defined(__clang__)
+#  pragma GCC diagnostic pop
+#endif
+} // namespace std
+
+#endif // CONTINUABLE_RESULT_HPP_INCLUDED

include/continuable/continuable-trait.hpp

@@ -1,74 +0,0 @@
-
-/*
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v3.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#ifndef CONTINUABLE_TRAIT_HPP_INCLUDED
-#define CONTINUABLE_TRAIT_HPP_INCLUDED
-
-#include <cstdint>
-
-#include <continuable/continuable-base.hpp>
-#include <continuable/continuable-promise-base.hpp>
-#include <continuable/detail/hints.hpp>
-#include <continuable/detail/types.hpp>
-
-namespace cti {
-/// Trait to retrieve a continuable_base type with a given type-erasure backend.
-///
-/// Every object may me used as type-erasure backend as long as the
-/// requirements of a `std::function` like wrapper are satisfied.
-///
-/// \tparam CallbackWrapper The type which is used to erase the callback.
-///
-/// \tparam ContinuationWrapper The type which is used to erase the
-///         continuation data.
-///
-/// \tparam Args The current signature of the continuable.
-template <template <std::size_t, typename...> class CallbackWrapper,
-          template <std::size_t, typename...> class ContinuationWrapper,
-          typename... Args>
-class continuable_trait {
-
-  using callback = CallbackWrapper<0U, void(Args...)&&,
-                                   void(detail::types::dispatch_error_tag,
-                                        detail::types::error_type) &&>;
-
-public:
-  /// The promise type which is used to resolve continuations
-  using promise =
-      promise_base<callback, detail::hints::signature_hint_tag<Args...>>;
-
-  /// The continuable type for the given parameters.
-  using continuable =
-      continuable_base<ContinuationWrapper<sizeof(callback), void(promise)>,
-                       detail::hints::signature_hint_tag<Args...>>;
-};
-} // namespace cti
-
-#endif // CONTINUABLE_TRAIT_HPP_INCLUDED

include/continuable/continuable-transforms.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -31,72 +31,22 @@
 #ifndef CONTINUABLE_TRANSFORMS_HPP_INCLUDED
 #define CONTINUABLE_TRANSFORMS_HPP_INCLUDED
 
-#include <continuable/detail/transforms.hpp>
+#include <continuable/transforms/wait.hpp>
-#include <continuable/detail/types.hpp>
+#include <continuable/transforms/future.hpp>
 
 namespace cti {
-/// A callable tag object which marks a wrapped callable object
+/// \defgroup Transforms Transforms
-/// as continuable transformation which enables some useful overloads.
+/// provides utilities to convert
-///
+/// \link continuable_base continuable_bases\endlink to other
-/// \since 3.0.0
+/// types such as (`std::future`).
-using detail::types::transform;
+/// \{
-
-/// Wraps the given callable object into a transform class.
-///
-/// \since 3.0.0
-template <typename T>
-auto make_transform(T&& callable) {
-  return transform<std::decay_t<T>>(std::forward<T>(callable));
-}
 
 /// The namespace transforms declares callable objects that transform
 /// any continuable_base to an object or to a continuable_base itself.
 ///
 /// Transforms can be applied to continuables through using
 /// the cti::continuable_base::apply method accordingly.
-namespace transforms {
+namespace transforms {}
-/// Returns a transform that if applied to a continuable,
-/// it will start the continuation chain and returns the asynchronous
-/// result as `std::future<...>`.
-///
-/// \returns Returns a `std::future<...>` which becomes ready as soon
-///          as the the continuation chain has finished.
-///          The signature of the future depends on the result type:
-/// |          Continuation type        |             Return type            |
-/// | : ------------------------------- | : -------------------------------- |
-/// | `continuable_base with <>`        | `std::future<void>`                |
-/// | `continuable_base with <Arg>`     | `std::future<Arg>`                 |
-/// | `continuable_base with <Args...>` | `std::future<std::tuple<Args...>>` |
-///
-/// \attention If exceptions are used, exceptions that are thrown, are forwarded
-///            to the returned future. If there are no exceptions supported,
-///            you shall not pass any errors to the end of the asynchronous
-///            call chain!
-///            Otherwise this will yield a trap that causes application exit.
-///
-/// \since 2.0.0
-inline auto futurize() {
-  return make_transform([](auto&& continuable) {
-    using detail::transforms::as_future;
-    return as_future(std::forward<decltype(continuable)>(continuable));
-  });
-}
-
-/// Returns a transform that if applied to a continuable, it will ignores all
-/// error which ocured until the point the transform was applied.
-///
-/// \returns Returns a continuable with the same signature as applied to.
-///
-/// \attention This can be used to create a continuable which doesn't resolve
-///            the continuation on errors.
-///
-/// \since 2.0.0
-inline auto flatten() {
-  return make_transform([](auto&& continuable) {
-    return std::forward<decltype(continuable)>(continuable).fail([](auto&&) {});
-  });
-}
-} // namespace transforms
 } // namespace cti
 
 #endif // CONTINUABLE_TRANSFORMS_HPP_INCLUDED

include/continuable/continuable-traverse-async.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -32,31 +32,37 @@
 #define CONTINUABLE_TRAVERSE_ASYNC_HPP_INCLUDED
 
 #include <utility>
-
+#include <continuable/detail/traversal/traverse-async.hpp>
-#include <continuable/detail/traverse-async.hpp>
 
 namespace cti {
+/// \defgroup Traversal Traversal
+/// provides functions to traverse and remap nested packs.
+/// \{
+
 /// A tag which is passed to the `operator()` of the visitor
-/// if an element is visited synchronously.
+/// if an element is visited synchronously through \ref traverse_pack_async.
 ///
 /// \since 3.0.0
-using detail::traversal::async_traverse_visit_tag;
+using async_traverse_visit_tag = detail::traversal::async_traverse_visit_tag;
-/// A tag which is passed to the `operator()` of the visitor
+/// A tag which is passed to the `operator()` of the visitor if an element is
-/// if an element is visited after the traversal was detached.
+/// visited after the traversal was detached through \ref traverse_pack_async.
 ///
 /// \since 3.0.0
-using detail::traversal::async_traverse_detach_tag;
+using async_traverse_detach_tag = detail::traversal::async_traverse_detach_tag;
-/// A tag which is passed to the `operator()` of the visitor
+/// A tag which is passed to the `operator()` of the visitor if the
-/// if the asynchronous pack traversal was finished.
+/// asynchronous pack traversal was finished through \ref traverse_pack_async.
 ///
 /// \since 3.0.0
-using detail::traversal::async_traverse_complete_tag;
+using async_traverse_complete_tag =
+    detail::traversal::async_traverse_complete_tag;
 
 /// A tag to identify that a mapper shall be constructed in-place
-/// from the first argument passed.
+/// from the first argument passed to \ref traverse_pack_async.
 ///
 /// \since 3.0.0
-using detail::traversal::async_traverse_in_place_tag;
+template <typename T>
+using async_traverse_in_place_tag =
+    detail::traversal::async_traverse_in_place_tag<T>;
 
 /// Traverses the pack with the given visitor in an asynchronous way.
 ///
@@ -68,7 +74,7 @@ using detail::traversal::async_traverse_in_place_tag;
 ///    ```cpp
 ///    struct my_async_visitor {
 ///      /// The synchronous overload is called for each object,
-///      /// it may return false to suspend the current control.
+///      /// it may return false to suspend the current control flow.
 ///      /// In that case the overload below is called.
 ///      template <typename T>
 ///      bool operator()(async_traverse_visit_tag, T&& element) {
@@ -118,6 +124,7 @@ auto traverse_pack_async(Visitor&& visitor, T&&... pack) {
   return detail::traversal::apply_pack_transform_async(
       std::forward<Visitor>(visitor), std::forward<T>(pack)...);
 }
+/// \}
 } // namespace cti
 
 #endif // CONTINUABLE_TRAVERSE_ASYNC_HPP_INCLUDED

include/continuable/continuable-traverse.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -34,10 +34,13 @@
 #include <tuple>
 #include <type_traits>
 #include <utility>
-
+#include <continuable/detail/traversal/traverse.hpp>
-#include <continuable/detail/traverse.hpp>
 
 namespace cti {
+/// \defgroup Traversal Traversal
+/// provides functions to traverse and remap nested packs.
+/// \{
+
 /// Maps the pack with the given mapper.
 ///
 /// This function tries to visit all plain elements which may be wrapped in:
@@ -106,6 +109,7 @@ void traverse_pack(Mapper&& mapper, T&&... pack) {
                                std::forward<Mapper>(mapper),
                                std::forward<T>(pack)...);
 }
+/// \}
 } // namespace cti
 
 #endif // CONTINUABLE_TRAVERSE_HPP_INCLUDED

include/continuable/continuable-types.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -31,78 +31,72 @@
 #ifndef CONTINUABLE_TYPES_HPP_INCLUDED
 #define CONTINUABLE_TYPES_HPP_INCLUDED
 
-#include <cstdint>
-
 #include <function2/function2.hpp>
-
+#include <continuable/continuable-base.hpp>
-#include <continuable/continuable-trait.hpp>
+#include <continuable/continuable-primitives.hpp>
+#include <continuable/continuable-promise-base.hpp>
+#include <continuable/detail/other/erasure.hpp>
 
 namespace cti {
-// clang-format off
+/// \defgroup Types Types
-namespace detail {
+/// provides the \link cti::continuable continuable\endlink and \link
-/// A function which isn't size adjusted and copyable
+/// cti::promise promise\endlink facility for type erasure.
-template<std::size_t Size, typename... Args>
+/// \{
-using function_adapter = fu2::function<Args...>;
-/// A function which isn't size adjusted and move only
-template<std::size_t, typename... Args>
-using unique_function_adapter = fu2::unique_function<Args...>;
-/// A function which is size adjusted and copyable
-template<std::size_t Size, typename... Args>
-using function_adjustable = fu2::function_base<true, true, Size,
-                                               true, false, Args...>;
-/// A function which is size adjusted and move only
-template<std::size_t Size, typename... Args>
-using unique_function_adjustable = fu2::function_base<true, false, Size,
-                                                      true, false, Args...>;
 
-/// We adjust the internal capacity of the outer function wrapper so
+/// Deduces to the preferred continuation capacity for a possible
-/// we don't have to allocate twice when using `continuable<...>`.
+/// small functor optimization. The given capacity size is always enough to
-template<typename... Args>
+/// to avoid any allocation when storing a ready continuable_base.
-using trait_of = continuable_trait<
-  unique_function_adapter,
-  function_adjustable,
-  Args...
->;
-
-template<typename... Args>
-using unique_trait_of = continuable_trait<
-  unique_function_adapter,
-  unique_function_adjustable,
-  Args...
->;
-} // namespace detail
-
-/// Defines a copyable continuation type which uses the
-/// function2 backend for type erasure.
 ///
-/// Usable like: `cti::continuable<int, float>`
+/// \since 4.0.0
 template <typename... Args>
-using continuable = typename detail::trait_of<
+using continuation_capacity = detail::erasure::continuation_capacity<Args...>;
-  Args...
->::continuable;
 
 /// Defines a non-copyable continuation type which uses the
 /// function2 backend for type erasure.
 ///
-/// Usable like: `unique_continuable<int, float>`
+/// Usable like: `continuable<int, float>`
+///
+/// \note You can always define your own continuable with a type erasure of
+///       choice, the type erasure wrapper just needs to accept a
+///       callable object with a continuation signature as specified
+///       in the Primitives section.
+///
+/// \since 1.0.0
 template <typename... Args>
-using unique_continuable = typename detail::unique_trait_of<
+using continuable = continuable_base<detail::erasure::continuation<Args...>, //
-  Args...
+                                     signature_arg_t<Args...>>;
->::continuable;
 
 /// Defines a non-copyable promise type which is using the
 /// function2 backend for type erasure.
 ///
 /// Usable like: `promise<int, float>`
+///
+/// \note You can always define your own promise with a type erasure of
+///       choice, the type erasure wrapper just needs to accept a
+///       callable object with a callback signature as specified
+///       in the Primitives section.
+///
+/// \since 1.0.0
 template <typename... Args>
-using promise = typename detail::unique_trait_of<
+using promise = promise_base<detail::erasure::callback<Args...>, //
-  Args...
+                             signature_arg_t<Args...>>;
->::promise;
 
-// TODO channel
+/// Defines a non-copyable type erasure which is capable of carrying
-// TODO sink
+/// callable objects passed to executors.
-
+///
-// clang-format on
+/// The work behaves like a `promise<>` but the work type erasure uses extra
+/// stack space for small object optimization.
+/// Additionally the outstanding work can be resolved through an exception.
+///
+/// \note You can always define your own cancelable_work with a type erasure of
+///       choice, the type erasure wrapper just needs to accept a
+///       callable object which is callable with a `void()` and
+///       `void(exception_arg_t, exception_t)` signature.
+///
+/// \since 4.0.0
+using work = promise_base<detail::erasure::work, //
+                          signature_arg_t<>>;
+/// \}
 } // namespace cti
 
 #endif // CONTINUABLE_TYPES_HPP_INCLUDED

include/continuable/continuable.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -46,10 +46,13 @@
 namespace cti {}
 
 #include <continuable/continuable-base.hpp>
-#include <continuable/continuable-compositions.hpp>
+#include <continuable/continuable-connections.hpp>
+#include <continuable/continuable-coroutine.hpp>
+#include <continuable/continuable-operations.hpp>
+#include <continuable/continuable-primitives.hpp>
 #include <continuable/continuable-promise-base.hpp>
 #include <continuable/continuable-promisify.hpp>
-#include <continuable/continuable-trait.hpp>
+#include <continuable/continuable-result.hpp>
 #include <continuable/continuable-transforms.hpp>
 #include <continuable/continuable-traverse-async.hpp>
 #include <continuable/continuable-traverse.hpp>

include/continuable/detail/awaiting.hpp

@@ -1,164 +0,0 @@
-
-/*
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v3.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#ifndef CONTINUABLE_DETAIL_AWAITING_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_AWAITING_HPP_INCLUDED
-
-// Exlude this header when coroutines are not available
-#ifdef CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE
-
-#include <cassert>
-#include <experimental/coroutine>
-
-#include <continuable/detail/base.hpp>
-#include <continuable/detail/expected.hpp>
-#include <continuable/detail/features.hpp>
-#include <continuable/detail/hints.hpp>
-#include <continuable/detail/types.hpp>
-#include <continuable/detail/util.hpp>
-
-#if defined(CONTINUABLE_HAS_EXCEPTIONS)
-#include <exception>
-#endif // CONTINUABLE_HAS_EXCEPTIONS
-
-namespace cti {
-namespace detail {
-namespace awaiting {
-/// We import the coroutine handle in our namespace
-using std::experimental::coroutine_handle;
-
-/// An object which provides the internal buffer and helper methods
-/// for waiting on a continuable in a stackless coroutine.
-template <typename Continuable>
-class awaitable {
-  using trait_t = util::expected_result_trait_t<Continuable>;
-
-  /// The continuable which is invoked upon suspension
-  Continuable continuable_;
-  /// A cache which is used to pass the result of the continuation
-  /// to the coroutine.
-  typename trait_t::expected_type result_;
-
-public:
-  explicit constexpr awaitable(Continuable&& continuable)
-      : continuable_(std::move(continuable)) {
-  }
-
-  /// Since continuables are evaluated lazily we are not
-  /// capable to say whether the resumption will be instantly.
-  bool await_ready() const noexcept {
-    return false;
-  }
-
-  /// Suspend the current context
-  // TODO Convert this to an r-value function once possible
-  void await_suspend(coroutine_handle<> h) {
-    // Forward every result to the current awaitable
-    std::move(continuable_)
-        .next([h, this](auto&&... args) mutable {
-          resolve(std::forward<decltype(args)>(args)...);
-          h.resume();
-        })
-        .done();
-  }
-
-  /// Resume the coroutine represented by the handle
-  auto await_resume() noexcept(false) {
-    if (result_) {
-      // When the result was resolved return it
-      return trait_t::unwrap(std::move(result_));
-    }
-
-#if defined(CONTINUABLE_HAS_EXCEPTIONS)
-    std::rethrow_exception(result_.get_exception());
-#else  // CONTINUABLE_HAS_EXCEPTIONS
-    // Returning error types in await isn't supported as of now
-    util::trap();
-#endif // CONTINUABLE_HAS_EXCEPTIONS
-  }
-
-private:
-  /// Resolve the continuation through the result
-  template <typename... Args>
-  void resolve(Args&&... args) {
-    result_.set_value(trait_t::wrap(std::forward<Args>(args)...));
-  }
-
-  /// Resolve the continuation through an error
-  void resolve(types::dispatch_error_tag, types::error_type error) {
-    result_.set_exception(std::move(error));
-  }
-};
-
-/// Converts a continuable into an awaitable object as described by
-/// the C++ coroutine TS.
-template <typename T>
-constexpr auto create_awaiter(T&& continuable) {
-  return awaitable<std::decay_t<T>>(std::forward<T>(continuable));
-}
-} // namespace awaiting
-} // namespace detail
-} // namespace cti
-
-namespace std {
-namespace experimental {
-template <typename Data, typename... Args, typename... FunctionArgs>
-struct coroutine_traits<
-    cti::continuable_base<Data,
-                          cti::detail::hints::signature_hint_tag<Args...>>,
-    FunctionArgs...> /*{
-  struct promise_type {
-    // boost::promise<R> p;
-    auto get_return_object() {
-      // return p.get_future();
-    }
-    suspend_always initial_suspend() {
-      return {};
-    }
-    suspend_never final_suspend() {
-      return {};
-    }
-    void set_exception(std::exception_ptr e) {
-      // p.set_exception(std::move(e));
-    }
-    void unhandled_exception() {
-      // p.set_exception(std::current_exception());
-    }
-    template <typename U>
-    void return_value(U&& u) {
-      // p.set_value(std::forward<U>(u));
-    }
-  };
-}*/;
-} // namespace experimental
-} // namespace std
-
-#endif // CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE
-#endif // CONTINUABLE_DETAIL_UTIL_HPP_INCLUDED

include/continuable/detail/base.hpp

@@ -1,590 +0,0 @@
-
-/*
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v3.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#ifndef CONTINUABLE_DETAIL_BASE_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_BASE_HPP_INCLUDED
-
-#include <tuple>
-#include <type_traits>
-#include <utility>
-
-#include <continuable/detail/features.hpp>
-#include <continuable/detail/hints.hpp>
-#include <continuable/detail/traits.hpp>
-#include <continuable/detail/types.hpp>
-#include <continuable/detail/util.hpp>
-
-#if defined(CONTINUABLE_HAS_EXCEPTIONS)
-#include <exception>
-#endif // CONTINUABLE_HAS_EXCEPTIONS
-
-namespace cti {
-namespace detail {
-/// The namespace `base` provides the low level API for working
-/// with continuable types.
-///
-/// Important methods are:
-/// - Creating a continuation from a callback taking functional
-///   base::attorney::create(auto&& callback)
-///     -> base::continuation<auto>
-/// - Chaining a continuation together with a callback
-///   base::chain_continuation(base::continuation<auto> continuation,
-///                            auto&& callback)
-///     -> base::continuation<auto>
-/// - Finally invoking the continuation chain
-///    base::finalize_continuation(base::continuation<auto> continuation)
-///     -> void
-namespace base {
-template <typename T>
-struct is_continuable : std::false_type {};
-template <typename Data, typename Annotation>
-struct is_continuable<continuable_base<Data, Annotation>> : std::true_type {};
-
-/// Helper class to access private methods and members of
-/// the continuable_base class.
-struct attorney {
-  /// Makes a continuation wrapper from the given argument
-  template <typename T, typename A>
-  static auto create(T&& continuation, A /*hint*/, util::ownership ownership_) {
-    return continuable_base<std::decay_t<T>, std::decay_t<A>>(
-        std::forward<T>(continuation), ownership_);
-  }
-
-  /// Invokes a continuation object in a reference correct way
-  template <typename Data, typename Annotation, typename Callback>
-  static auto
-  invoke_continuation(continuable_base<Data, Annotation>&& continuation,
-                      Callback&& callback) noexcept {
-    auto materialized = std::move(continuation).materialize();
-    materialized.release();
-    return materialized.data_(std::forward<Callback>(callback));
-  }
-
-  template <typename Data, typename Annotation>
-  static auto materialize(continuable_base<Data, Annotation>&& continuation) {
-    return std::move(continuation).materialize();
-  }
-
-  template <typename Data, typename Annotation>
-  static Data&&
-  consume_data(continuable_base<Data, Annotation>&& continuation) {
-    return std::move(continuation).consume_data();
-  }
-
-  template <typename Continuable>
-  static util::ownership ownership_of(Continuable&& continuation) noexcept {
-    return continuation.ownership_;
-  }
-};
-
-// Returns the invoker of a callback, the next callback
-// and the arguments of the previous continuation.
-//
-// The return type of the invokerOf function matches a callable of:
-//   void(auto&& callback, auto&& next_callback, auto&&... args)
-//
-// The invoker decorates the result type in the following way
-// - void              -> next_callback()
-// - ?                 -> next_callback(?)
-// - std::pair<?, ?>   -> next_callback(?, ?)
-// - std::tuple<?...>  -> next_callback(?...)
-//
-// When the result is a continuation itself pass the callback to it
-// - continuation<?...> -> result(next_callback);
-namespace decoration {
-/// Helper class wrapping the underlaying unwrapping lambda
-/// in order to extend it with a hint method.
-template <typename T, typename Hint>
-class invoker : public T {
-public:
-  constexpr explicit invoker(T invoke) : T(std::move(invoke)) {
-  }
-
-  using T::operator();
-
-  /// Returns the underlaying signature hint
-  static constexpr Hint hint() noexcept {
-    return {};
-  }
-};
-
-#if defined(CONTINUABLE_HAS_EXCEPTIONS)
-#define CONTINUABLE_BLOCK_TRY_BEGIN try {
-#define CONTINUABLE_BLOCK_TRY_END                                              \
-  }                                                                            \
-  catch (...) {                                                                \
-    std::forward<decltype(next_callback)>(next_callback)(                      \
-        types::dispatch_error_tag{}, std::current_exception());                \
-  }
-
-#else // CONTINUABLE_HAS_EXCEPTIONS
-#define CONTINUABLE_BLOCK_TRY_BEGIN {
-#define CONTINUABLE_BLOCK_TRY_END }
-#endif // CONTINUABLE_HAS_EXCEPTIONS
-
-/// Invokes the given callable object with the given arguments while
-/// marking the operation as non exceptional.
-template <typename T, typename... Args>
-constexpr auto invoke_no_except(T&& callable, Args&&... args) noexcept {
-  return std::forward<T>(callable)(std::forward<Args>(args)...);
-}
-
-template <typename T, typename... Args>
-constexpr auto make_invoker(T&& invoke, hints::signature_hint_tag<Args...>) {
-  return invoker<std::decay_t<T>, hints::signature_hint_tag<Args...>>(
-      std::forward<T>(invoke));
-}
-
-/// - continuable<?...> -> result(next_callback);
-template <typename Data, typename Annotation>
-constexpr auto
-invoker_of(traits::identity<continuable_base<Data, Annotation>>) {
-  /// Get the hint of the unwrapped returned continuable
-  using Type = decltype(attorney::materialize(
-      std::declval<continuable_base<Data, Annotation>>()));
-
-  auto constexpr const hint = hints::hint_of(traits::identify<Type>{});
-
-  return make_invoker(
-      [](auto&& callback, auto&& next_callback, auto&&... args) {
-        CONTINUABLE_BLOCK_TRY_BEGIN
-          auto continuation_ =
-              util::partial_invoke(std::forward<decltype(callback)>(callback),
-                                   std::forward<decltype(args)>(args)...);
-
-          attorney::invoke_continuation(
-              std::move(continuation_),
-              std::forward<decltype(next_callback)>(next_callback));
-        CONTINUABLE_BLOCK_TRY_END
-      },
-      hint);
-}
-
-/// - ? -> next_callback(?)
-template <typename T>
-constexpr auto invoker_of(traits::identity<T>) {
-  return make_invoker(
-      [](auto&& callback, auto&& next_callback, auto&&... args) {
-        CONTINUABLE_BLOCK_TRY_BEGIN
-          auto result =
-              util::partial_invoke(std::forward<decltype(callback)>(callback),
-                                   std::forward<decltype(args)>(args)...);
-
-          invoke_no_except(std::forward<decltype(next_callback)>(next_callback),
-                           std::move(result));
-        CONTINUABLE_BLOCK_TRY_END
-      },
-      traits::identify<T>{});
-}
-
-/// - void -> next_callback()
-inline auto invoker_of(traits::identity<void>) {
-  return make_invoker(
-      [](auto&& callback, auto&& next_callback, auto&&... args) {
-        CONTINUABLE_BLOCK_TRY_BEGIN
-          util::partial_invoke(std::forward<decltype(callback)>(callback),
-                               std::forward<decltype(args)>(args)...);
-          invoke_no_except(
-              std::forward<decltype(next_callback)>(next_callback));
-        CONTINUABLE_BLOCK_TRY_END
-      },
-      traits::identity<>{});
-}
-
-/// Returns a sequenced invoker which is able to invoke
-/// objects where std::get is applicable.
-inline auto sequenced_unpack_invoker() {
-  return [](auto&& callback, auto&& next_callback, auto&&... args) {
-    CONTINUABLE_BLOCK_TRY_BEGIN
-      auto result =
-          util::partial_invoke(std::forward<decltype(callback)>(callback),
-                               std::forward<decltype(args)>(args)...);
-
-      // Workaround for MSVC not capturing the reference correctly inside
-      // the lambda.
-      using Next = decltype(next_callback);
-
-      traits::unpack(std::move(result), [&](auto&&... types) {
-        /// TODO Add inplace resolution here
-
-        invoke_no_except(std::forward<Next>(next_callback),
-                         std::forward<decltype(types)>(types)...);
-      });
-    CONTINUABLE_BLOCK_TRY_END
-  };
-} // namespace decoration
-
-// - std::pair<?, ?> -> next_callback(?, ?)
-template <typename First, typename Second>
-constexpr auto invoker_of(traits::identity<std::pair<First, Second>>) {
-  return make_invoker(sequenced_unpack_invoker(),
-                      traits::identity<First, Second>{});
-}
-
-// - std::tuple<?...>  -> next_callback(?...)
-template <typename... Args>
-constexpr auto invoker_of(traits::identity<std::tuple<Args...>>) {
-  return make_invoker(sequenced_unpack_invoker(), traits::identity<Args...>{});
-}
-
-#undef CONTINUABLE_BLOCK_TRY_BEGIN
-#undef CONTINUABLE_BLOCK_TRY_END
-} // namespace decoration
-
-/// Invoke the callback immediately
-template <typename Invoker, typename... Args>
-void packed_dispatch(types::this_thread_executor_tag, Invoker&& invoker,
-                     Args&&... args) {
-
-  // Invoke the callback with the decorated invoker immediately
-  std::forward<Invoker>(invoker)(std::forward<Args>(args)...);
-}
-
-/// Invoke the callback through the given executor
-template <typename Executor, typename Invoker, typename... Args>
-void packed_dispatch(Executor&& executor, Invoker&& invoker, Args&&... args) {
-
-  // Create a worker object which when invoked calls the callback with the
-  // the returned arguments.
-  auto work = [
-    invoker = std::forward<Invoker>(invoker),
-    args = std::make_tuple(std::forward<Args>(args)...)
-  ]() mutable {
-    traits::unpack(std::move(args), [&](auto&&... captured_args) {
-      // Just use the packed dispatch method which dispatches the work on
-      // the current thread.
-      packed_dispatch(types::this_thread_executor_tag{}, std::move(invoker),
-                      std::forward<decltype(captured_args)>(captured_args)...);
-    });
-  };
-
-  // Pass the work callable object to the executor
-  std::forward<Executor>(executor)(std::move(work));
-}
-
-/// Tells whether we potentially move the chain upwards and handle the result
-enum class handle_results {
-  no, //< The result is forwarded to the next callable
-  yes //< The result is handled by the current callable
-};
-
-/// Tells whether we handle the error through the callback
-enum class handle_errors {
-  no,     //< The error is forwarded to the next callable
-  plain,  //< The error is the only argument accepted by the callable
-  forward //< The error is forwarded to the callable while keeping its tag
-};
-
-namespace callbacks {
-namespace proto {
-template <handle_results HandleResults, typename Base, typename Hint>
-struct result_handler_base;
-template <typename Base, typename... Args>
-struct result_handler_base<handle_results::no, Base,
-                           hints::signature_hint_tag<Args...>> {
-  void operator()(Args... args) && {
-    // Forward the arguments to the next callback
-    std::move(static_cast<Base*>(this)->next_callback_)(std::move(args)...);
-  }
-};
-template <typename Base, typename... Args>
-struct result_handler_base<handle_results::yes, Base,
-                           hints::signature_hint_tag<Args...>> {
-  /// The operator which is called when the result was provided
-  void operator()(Args... args) && {
-    // In order to retrieve the correct decorator we must know what the
-    // result type is.
-    auto result = traits::identify<decltype(util::partial_invoke(
-        std::move(static_cast<Base*>(this)->callback_), std::move(args)...))>{};
-
-    // Pick the correct invoker that handles decorating of the result
-    auto invoker = decoration::invoker_of(result);
-
-    // Invoke the callback
-    packed_dispatch(std::move(static_cast<Base*>(this)->executor_),
-                    std::move(invoker),
-                    std::move(static_cast<Base*>(this)->callback_),
-                    std::move(static_cast<Base*>(this)->next_callback_),
-                    std::move(args)...);
-  }
-};
-
-inline auto make_error_invoker(
-    std::integral_constant<handle_errors, handle_errors::plain>) noexcept {
-  return [](auto&& callback, types::error_type&& error) {
-    // Errors are not partial invoked
-    // NOLINTNEXTLINE(hicpp-move-const-arg)
-    std::forward<decltype(callback)>(callback)(std::move(error));
-  };
-}
-inline auto make_error_invoker(
-    std::integral_constant<handle_errors, handle_errors::forward>) noexcept {
-  return [](auto&& callback, types::error_type&& error) {
-    // Errors are not partial invoked
-    std::forward<decltype(callback)>(callback)(
-        types::dispatch_error_tag{},
-        std::move(error)); // NOLINT(hicpp-move-const-arg)
-  };
-}
-
-template <handle_errors HandleErrors /* = plain or forward*/, typename Base>
-struct error_handler_base {
-  void operator()(types::dispatch_error_tag, types::error_type error) && {
-    // Just invoke the error handler, cancel the calling hierarchy after
-    auto invoker = make_error_invoker(
-        std::integral_constant<handle_errors, HandleErrors>{});
-
-    // Invoke the error handler
-    packed_dispatch(
-        std::move(static_cast<Base*>(this)->executor_), std::move(invoker),
-        std::move(static_cast<Base*>(this)->callback_), std::move(error));
-  }
-};
-template <typename Base>
-struct error_handler_base<handle_errors::no, Base> {
-  /// The operator which is called when an error occurred
-  void operator()(types::dispatch_error_tag tag, types::error_type error) && {
-    // Forward the error to the next callback
-    std::move(static_cast<Base*>(this)->next_callback_)(tag, std::move(error));
-  }
-};
-} // namespace proto
-
-template <typename Hint, handle_results HandleResults,
-          handle_errors HandleErrors, typename Callback, typename Executor,
-          typename NextCallback>
-struct callback_base;
-
-template <typename... Args, handle_results HandleResults,
-          handle_errors HandleErrors, typename Callback, typename Executor,
-          typename NextCallback>
-struct callback_base<hints::signature_hint_tag<Args...>, HandleResults,
-                     HandleErrors, Callback, Executor, NextCallback>
-    : proto::result_handler_base<
-          HandleResults,
-          callback_base<hints::signature_hint_tag<Args...>, HandleResults,
-                        HandleErrors, Callback, Executor, NextCallback>,
-          hints::signature_hint_tag<Args...>>,
-      proto::error_handler_base<
-          HandleErrors,
-          callback_base<hints::signature_hint_tag<Args...>, HandleResults,
-                        HandleErrors, Callback, Executor, NextCallback>>,
-      util::non_copyable {
-
-  Callback callback_;
-  Executor executor_;
-  NextCallback next_callback_;
-
-  explicit callback_base(Callback callback, Executor executor,
-                         NextCallback next_callback)
-      : callback_(std::move(callback)), executor_(std::move(executor)),
-        next_callback_(std::move(next_callback)) {
-  }
-
-  /// Pull the result handling operator() in
-  using proto::result_handler_base<
-      HandleResults,
-      callback_base<hints::signature_hint_tag<Args...>, HandleResults,
-                    HandleErrors, Callback, Executor, NextCallback>,
-      hints::signature_hint_tag<Args...>>::operator();
-
-  /// Pull the error handling operator() in
-  using proto::error_handler_base<
-      HandleErrors,
-      callback_base<hints::signature_hint_tag<Args...>, HandleResults,
-                    HandleErrors, Callback, Executor, NextCallback>>::
-  operator();
-
-  /// Resolves the continuation with the given values
-  void set_value(Args... args) {
-    std::move (*this)(std::move(args)...);
-  }
-
-  /// Resolves the continuation with the given error variable.
-  void set_exception(types::error_type error) {
-    std::move (*this)(types::dispatch_error_tag{}, std::move(error));
-  }
-};
-
-template <typename Hint, handle_results HandleResults,
-          handle_errors HandleErrors, typename Callback, typename Executor,
-          typename NextCallback>
-auto make_callback(Callback&& callback, Executor&& executor,
-                   NextCallback&& next_callback) {
-  return callback_base<Hint, HandleResults, HandleErrors,
-                       std::decay_t<Callback>, std::decay_t<Executor>,
-                       std::decay_t<NextCallback>>{
-      std::forward<Callback>(callback), std::forward<Executor>(executor),
-      std::forward<NextCallback>(next_callback)};
-}
-
-/// Once this was a workaround for GCC bug:
-/// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64095
-struct final_callback : util::non_copyable {
-  template <typename... Args>
-  void operator()(Args... /*args*/) && {
-  }
-
-  void operator()(types::dispatch_error_tag, types::error_type error) && {
-    (void)error;
-#ifndef CONTINUABLE_WITH_UNHANDLED_ERRORS
-    // There were unhandled errors inside the asynchronous call chain!
-    // Define `CONTINUABLE_WITH_UNHANDLED_ERRORS` in order
-    // to ignore unhandled errors!"
-    util::trap();
-#endif // CONTINUABLE_WITH_UNHANDLED_ERRORS
-  }
-
-  template <typename... Args>
-  void set_value(Args... args) {
-    std::move (*this)(std::forward<Args>(args)...);
-  }
-
-  void set_exception(types::error_type error) {
-    // NOLINTNEXTLINE(hicpp-move-const-arg)
-    std::move (*this)(types::dispatch_error_tag{}, std::move(error));
-  }
-};
-} // namespace callbacks
-
-/// Returns the next hint when the callback is invoked with the given hint
-template <typename T, typename... Args>
-constexpr auto
-next_hint_of(std::integral_constant<handle_results, handle_results::yes>,
-             traits::identity<T> /*callback*/,
-             hints::signature_hint_tag<Args...> /*current*/) {
-  // Partial Invoke the given callback
-  using Result = decltype(
-      util::partial_invoke(std::declval<T>(), std::declval<Args>()...));
-
-  // Return the hint of thr given invoker
-  return decltype(decoration::invoker_of(traits::identify<Result>{}).hint()){};
-}
-/// Don't progress the hint when we don't continue
-template <typename T, typename... Args>
-constexpr auto
-next_hint_of(std::integral_constant<handle_results, handle_results::no>,
-             traits::identity<T> /*callback*/,
-             hints::signature_hint_tag<Args...> current) {
-  return current;
-}
-
-/// Chains a callback together with a continuation and returns a continuation:
-///
-/// For example given:
-/// - Continuation: continuation<[](auto&& callback) { callback("hi"); }>
-/// - Callback: [](std::string) { }
-///
-/// This function returns a function accepting the next callback in the chain:
-/// - Result: continuation<[](auto&& callback) { /*...*/ }>
-///
-template <handle_results HandleResults, handle_errors HandleErrors,
-          typename Continuation, typename Callback, typename Executor>
-auto chain_continuation(Continuation&& continuation, Callback&& callback,
-                        Executor&& executor) {
-  static_assert(is_continuable<std::decay_t<Continuation>>{},
-                "Expected a continuation!");
-
-  using Hint = decltype(hints::hint_of(traits::identify<Continuation>()));
-  constexpr auto next_hint =
-      next_hint_of(std::integral_constant<handle_results, HandleResults>{},
-                   traits::identify<decltype(callback)>{}, Hint{});
-
-  // TODO consume only the data here so the freeze isn't needed
-  auto ownership_ = attorney::ownership_of(continuation);
-  continuation.freeze();
-
-  return attorney::create(
-      [
-        continuation = std::forward<Continuation>(continuation),
-        callback = std::forward<Callback>(callback),
-        executor = std::forward<Executor>(executor)
-      ](auto&& next_callback) mutable {
-
-        // Invokes a continuation with a given callback.
-        // Passes the next callback to the resulting continuable or
-        // invokes the next callback directly if possible.
-        //
-        // For example given:
-        // - Continuation: continuation<[](auto&& callback) { callback("hi"); }>
-        // - Callback: [](std::string) { }
-        // - NextCallback: []() { }
-        auto proxy =
-            callbacks::make_callback<Hint, HandleResults, HandleErrors>(
-                std::move(callback), std::move(executor),
-                std::forward<decltype(next_callback)>(next_callback));
-
-        // Invoke the continuation with a proxy callback.
-        // The proxy callback is responsible for passing
-        // the result to the callback as well as decorating it.
-        attorney::invoke_continuation(std::move(continuation),
-                                      std::move(proxy));
-      },
-      next_hint, ownership_);
-}
-
-/// Final invokes the given continuation chain:
-///
-/// For example given:
-/// - Continuation: continuation<[](auto&& callback) { callback("hi"); }>
-template <typename Continuation>
-void finalize_continuation(Continuation&& continuation) {
-  attorney::invoke_continuation(std::forward<Continuation>(continuation),
-                                callbacks::final_callback{});
-}
-
-/// Workaround for GCC bug:
-/// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64095
-template <typename T>
-class supplier_callback {
-  T data_;
-
-public:
-  explicit supplier_callback(T data) : data_(std::move(data)) {
-  }
-
-  template <typename... Args>
-  auto operator()(Args...) {
-    return std::move(data_);
-  }
-};
-
-/// Returns a continuable into a callable object returning the continuable
-template <typename Continuation>
-auto wrap_continuation(Continuation&& continuation) {
-  continuation.freeze();
-  return supplier_callback<std::decay_t<Continuation>>(
-      std::forward<Continuation>(continuation));
-}
-} // namespace base
-} // namespace detail
-} // namespace cti
-
-#endif // CONTINUABLE_DETAIL_BASE_HPP_INCLUDED

include/continuable/detail/composition-all.hpp

@@ -1,233 +0,0 @@
-
-/*
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v3.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#ifndef CONTINUABLE_DETAIL_COMPOSITION_ALL_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_COMPOSITION_ALL_HPP_INCLUDED
-
-#include <atomic>
-#include <memory>
-#include <mutex>
-#include <tuple>
-#include <type_traits>
-#include <utility>
-
-#include <continuable/detail/base.hpp>
-#include <continuable/detail/composition-remapping.hpp>
-#include <continuable/detail/composition.hpp>
-#include <continuable/detail/hints.hpp>
-#include <continuable/detail/traits.hpp>
-#include <continuable/detail/types.hpp>
-
-namespace cti {
-namespace detail {
-namespace composition {
-namespace all {
-struct all_hint_deducer {
-  static constexpr auto deduce(hints::signature_hint_tag<>) noexcept {
-    return spread_this();
-  }
-
-  template <typename First>
-  static constexpr auto deduce(hints::signature_hint_tag<First>) {
-    return First{};
-  }
-
-  template <typename First, typename Second, typename... Args>
-  static constexpr auto
-  deduce(hints::signature_hint_tag<First, Second, Args...>) {
-    return spread_this(First{}, Second{}, Args{}...);
-  }
-
-  template <
-      typename T,
-      std::enable_if_t<base::is_continuable<std::decay_t<T>>::value>* = nullptr>
-  auto operator()(T&& /*continuable*/) const {
-    return deduce(hints::hint_of(traits::identify<T>{}));
-  }
-};
-
-constexpr auto deduce_from_pack(traits::identity<void>)
-    -> hints::signature_hint_tag<>;
-template <typename... T>
-constexpr auto deduce_from_pack(traits::identity<std::tuple<T...>>)
-    -> hints::signature_hint_tag<T...>;
-template <typename T>
-constexpr auto deduce_from_pack(traits::identity<T>)
-    -> hints::signature_hint_tag<T>;
-
-// We must guard the mapped type against to be void since this represents an
-// empty signature hint.
-template <typename Composition>
-constexpr auto deduce_hint(Composition&& /*composition*/) {
-  // Don't change this way since it addresses a GCC compiler bug:
-  // error: extra ';' [-Werror=pedantic]
-  //  std::declval<Composition>()))>{})){};
-  using mapped_t =
-      decltype(map_pack(all_hint_deducer{}, std::declval<Composition>()));
-  using deduced_t = decltype(deduce_from_pack(traits::identity<mapped_t>{}));
-  return deduced_t{};
-}
-
-/// Caches the partial results and invokes the callback when all results
-/// are arrived. This class is thread safe.
-template <typename Callback, typename Result>
-class result_submitter
-    : public std::enable_shared_from_this<result_submitter<Callback, Result>>,
-      public util::non_movable {
-
-  Callback callback_;
-  Result result_;
-
-  std::atomic<std::size_t> left_;
-  std::once_flag flag_;
-
-  // Invokes the callback with the cached result
-  void invoke() {
-    assert((left_ == 0U) && "Expected that the submitter is finished!");
-    std::atomic_thread_fence(std::memory_order_acquire);
-
-    // Call the final callback with the cleaned result
-    std::call_once(flag_, [&] {
-      remapping::finalize_data(std::move(callback_), std::move(result_));
-    });
-  }
-
-  // Completes one result
-  void complete_one() {
-    assert((left_ > 0U) && "Expected that the submitter isn't finished!");
-
-    auto const current = --left_;
-    if (!current) {
-      invoke();
-    }
-  }
-
-  template <typename Box>
-  struct partial_all_callback {
-    Box* box;
-    std::shared_ptr<result_submitter> me;
-
-    template <typename... Args>
-    void operator()(Args&&... args) && {
-
-      // Assign the result to the target
-      box->assign(std::forward<decltype(args)>(args)...);
-
-      // Complete one result
-      me->complete_one();
-    }
-
-    template <typename... PartialArgs>
-    void operator()(types::dispatch_error_tag tag, types::error_type error) && {
-      // We never complete the composition, but we forward the first error
-      // which was raised.
-      std::call_once(me->flag_, std::move(me->callback_), tag,
-                     std::move(error));
-    }
-  };
-
-public:
-  explicit result_submitter(Callback callback, Result&& result)
-      : callback_(std::move(callback)), result_(std::move(result)), left_(1) {
-  }
-
-  /// Creates a submitter which submits it's result into the storage
-  template <typename Box>
-  auto create_callback(Box* box) {
-    left_.fetch_add(1, std::memory_order_seq_cst);
-    return partial_all_callback<std::decay_t<Box>>{box,
-                                                   this->shared_from_this()};
-  }
-
-  /// Initially the counter is created with an initial count of 1 in order
-  /// to prevent that the composition is finished before all callbacks
-  /// were registered.
-  void accept() {
-    complete_one();
-  }
-
-  constexpr auto& head() noexcept {
-    return result_;
-  }
-};
-
-template <typename Submitter>
-struct continuable_dispatcher {
-  std::shared_ptr<Submitter>& submitter;
-
-  template <typename Box, std::enable_if_t<remapping::is_continuable_box<
-                              std::decay_t<Box>>::value>* = nullptr>
-  void operator()(Box&& box) const {
-    // Retrieve a callback from the submitter and attach it to the continuable
-    box.fetch().next(submitter->create_callback(std::addressof(box))).done();
-  }
-};
-} // namespace all
-
-/// Finalizes the all logic of a given composition
-template <>
-struct composition_finalizer<composition_strategy_all_tag> {
-  template <typename Composition>
-  static constexpr auto hint() {
-    return decltype(all::deduce_hint(std::declval<Composition>())){};
-  }
-
-  /// Finalizes the all logic of a given composition
-  template <typename Composition>
-  static auto finalize(Composition&& composition) {
-    return [composition = std::forward<Composition>(composition)] // ...
-        (auto&& callback) mutable {
-
-      // Create the target result from the composition
-      auto result = remapping::box_continuables(std::move(composition));
-
-      using submitter_t =
-          all::result_submitter<std::decay_t<decltype(callback)>,
-                                std::decay_t<decltype(result)>>;
-
-      // Create the shared state which holds the result and the final callback
-      auto state = std::make_shared<submitter_t>(
-          std::forward<decltype(callback)>(callback), std::move(result));
-
-      // Dispatch the continuables and store its partial result
-      // in the whole result
-      traverse_pack(all::continuable_dispatcher<submitter_t>{state},
-                    state->head());
-
-      // Finalize the composition if all results arrived in-place
-      state->accept();
-    };
-  }
-};
-} // namespace composition
-} // namespace detail
-} // namespace cti
-
-#endif // CONTINUABLE_DETAIL_COMPOSITION_ALL_HPP_INCLUDED

include/continuable/detail/composition-seq.hpp

@@ -1,166 +0,0 @@
-
-/*
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v3.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#ifndef CONTINUABLE_DETAIL_COMPOSITION_SEQ_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_COMPOSITION_SEQ_HPP_INCLUDED
-
-#include <cassert>
-#include <memory>
-#include <tuple>
-#include <type_traits>
-#include <utility>
-
-#include <continuable/continuable-traverse-async.hpp>
-#include <continuable/detail/base.hpp>
-#include <continuable/detail/composition-all.hpp>
-#include <continuable/detail/composition-remapping.hpp>
-#include <continuable/detail/traits.hpp>
-#include <continuable/detail/util.hpp>
-
-namespace cti {
-namespace detail {
-namespace composition {
-namespace seq {
-/// Connects the left and the right continuable to a sequence
-///
-/// \note This is implemented in an eager way because we would not gain
-///       any profit from chaining sequences lazily.
-template <typename Left, typename Right>
-auto sequential_connect(Left&& left, Right&& right) {
-  left.freeze(right.is_frozen());
-  right.freeze();
-
-  return std::forward<Left>(left).then([right = std::forward<Right>(right)](
-      auto&&... args) mutable {
-    return std::move(right).then([previous = std::make_tuple(
-                                      std::forward<decltype(args)>(args)...)](
-        auto&&... args) mutable {
-      return traits::merge(
-          std::move(previous),
-          std::make_tuple(std::forward<decltype(args)>(args)...));
-    });
-  });
-}
-
-template <typename Callback, typename Box>
-struct sequential_dispatch_data {
-  Callback callback;
-  Box box;
-};
-
-template <typename Data>
-class sequential_dispatch_visitor
-    : public std::enable_shared_from_this<sequential_dispatch_visitor<Data>>,
-      public util::non_movable {
-
-  Data data_;
-
-public:
-  explicit sequential_dispatch_visitor(Data&& data) : data_(std::move(data)) {
-  }
-
-  virtual ~sequential_dispatch_visitor() = default;
-
-  /// Returns the pack that should be traversed
-  auto& head() {
-    return data_.box;
-  }
-
-  template <typename Box, std::enable_if_t<remapping::is_continuable_box<
-                              std::decay_t<Box>>::value>* = nullptr>
-  bool operator()(async_traverse_visit_tag, Box&& /*box*/) {
-    return false;
-  }
-
-  template <typename Box, typename N>
-  void operator()(async_traverse_detach_tag, Box&& box, N&& next) {
-    box.fetch()
-        .then([ box = std::addressof(box),
-                next = std::forward<N>(next) ](auto&&... args) mutable {
-
-          // Assign the result to the target
-          box->assign(std::forward<decltype(args)>(args)...);
-
-          // Continue the asynchronous sequential traversal
-          next();
-        })
-        .fail([me = this->shared_from_this()](types::error_type exception) {
-          // Abort the traversal when an error occurred
-          std::move(me->data_.callback)(types::dispatch_error_tag{},
-                                        std::move(exception));
-        })
-        .done();
-  }
-
-  template <typename T>
-  void operator()(async_traverse_complete_tag, T&& /*pack*/) {
-    return remapping::finalize_data(std::move(data_.callback),
-                                    std::move(data_.box));
-  }
-};
-} // namespace seq
-
-/// Finalizes the seq logic of a given composition
-template <>
-struct composition_finalizer<composition_strategy_seq_tag> {
-  template <typename Composition>
-  static constexpr auto hint() {
-    // The result is the same as in the all composition
-    using all_finalizer = composition_finalizer<composition_strategy_all_tag>;
-    return all_finalizer::hint<Composition>();
-  }
-
-  /// Finalizes the all logic of a given composition
-  template <typename Composition>
-  static auto finalize(Composition&& composition) {
-    return [composition = std::forward<Composition>(composition)] // ...
-        (auto&& callback) mutable {
-
-      auto boxed = remapping::box_continuables(std::move(composition));
-
-      // The data from which the visitor is constructed in-place
-      using data_t =
-          seq::sequential_dispatch_data<std::decay_t<decltype(callback)>,
-                                        std::decay_t<decltype(boxed)>>;
-
-      // The visitor type
-      using visitor_t = seq::sequential_dispatch_visitor<data_t>;
-
-      traverse_pack_async(
-          async_traverse_in_place_tag<visitor_t>{},
-          data_t{std::forward<decltype(callback)>(callback), std::move(boxed)});
-    };
-  }
-};
-} // namespace composition
-} // namespace detail
-} // namespace cti
-
-#endif // CONTINUABLE_DETAIL_COMPOSITION_SEQ_HPP_INCLUDED

include/continuable/detail/connection/connection-aggregated.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,77 +21,102 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_DETAIL_COMPOSITION_REMAPPING_HPP_INCLUDED
+#ifndef CONTINUABLE_DETAIL_CONNECTION_REMAPPING_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_COMPOSITION_REMAPPING_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_CONNECTION_REMAPPING_HPP_INCLUDED
 
+#include <cassert>
 #include <tuple>
 #include <type_traits>
 #include <utility>
-
+#include <continuable/continuable-result.hpp>
 #include <continuable/continuable-traverse.hpp>
-#include <continuable/detail/base.hpp>
+#include <continuable/detail/core/base.hpp>
-#include <continuable/detail/container-category.hpp>
+#include <continuable/detail/utility/traits.hpp>
-#include <continuable/detail/traits.hpp>
 
 namespace cti {
 namespace detail {
-namespace composition {
+namespace connection {
 /// This namespace provides utilities for performing compound
 /// connections between deeply nested continuables and values.
 ///
 /// We create the result pack from the provides values and
 /// the async values if those are default constructible,
 /// otherwise use a lazy initialization wrapper and unwrap
-/// the whole pack when the composition is finished.
+/// the whole pack when the connection is finished.
 ///   - value -> value
 ///   - single async value -> single value
 ///   - multiple async value -> tuple of async values.
-namespace remapping {
+namespace aggregated {
+
+/// Guards a type to be default constructible,
+/// and wraps it into an optional type if it isn't default constructible.
+template <typename T>
+using lazy_value_t = std::conditional_t<std::is_default_constructible<T>::value,
+                                        T, result<T>>;
+
+template <typename T>
+decltype(auto) unpack_lazy(std::true_type /*is_default_constructible*/,
+                           T&& value) {
+  return std::forward<T>(value);
+}
+template <typename T>
+T&& unpack_lazy(std::false_type /*is_default_constructible*/,
+                result<T>&& value) {
+  assert(value.is_value() &&
+         "The connection was finalized before all values were present!");
+
+  return std::move(value).get_value();
+}
+
 template <typename Continuable>
 class continuable_box;
 template <typename Data>
-class continuable_box<continuable_base<Data, hints::signature_hint_tag<>>> {
+class continuable_box<continuable_base<Data, identity<>>> {
 
-  continuable_base<Data, hints::signature_hint_tag<>> continuable_;
+  continuable_base<Data, identity<>> continuable_;
 
 public:
-  explicit continuable_box(
+  explicit continuable_box(continuable_base<Data, identity<>>&& continuable)
-      continuable_base<Data, hints::signature_hint_tag<>>&& continuable)
+    : continuable_(std::move(continuable)) {}
-      : continuable_(std::move(continuable)) {
+
+  auto const& peek() const {
+    return continuable_;
   }
 
-  continuable_base<Data, hints::signature_hint_tag<>>&& fetch() {
+  auto&& fetch() {
     return std::move(continuable_);
   }
 
-  void assign() {
+  void assign() {}
-  }
 
   auto unbox() && {
     return spread_this();
   }
 };
-template <typename Data, typename First>
-class continuable_box<
-    continuable_base<Data, hints::signature_hint_tag<First>>> {
 
-  continuable_base<Data, hints::signature_hint_tag<First>> continuable_;
+template <typename Data, typename First>
-  First first_;
+class continuable_box<continuable_base<Data, identity<First>>> {
+
+  continuable_base<Data, identity<First>> continuable_;
+  lazy_value_t<First> first_;
 
 public:
   explicit continuable_box(
-      continuable_base<Data, hints::signature_hint_tag<First>>&& continuable)
+      continuable_base<Data, identity<First>>&& continuable)
-      : continuable_(std::move(continuable)) {
+    : continuable_(std::move(continuable)) {}
+
+  auto const& peek() const {
+    return continuable_;
   }
 
-  continuable_base<Data, hints::signature_hint_tag<First>>&& fetch() {
+  auto&& fetch() {
     return std::move(continuable_);
   }
 
@@ -100,27 +125,27 @@ public:
   }
 
   auto unbox() && {
-    return std::move(first_);
+    return unpack_lazy(std::is_default_constructible<First>{},
+                       std::move(first_));
   }
 };
 template <typename Data, typename First, typename Second, typename... Rest>
 class continuable_box<
-    continuable_base<Data, hints::signature_hint_tag<First, Second, Rest...>>> {
+    continuable_base<Data, identity<First, Second, Rest...>>> {
 
-  continuable_base<Data, hints::signature_hint_tag<First, Second, Rest...>>
+  continuable_base<Data, identity<First, Second, Rest...>> continuable_;
-      continuable_;
+  lazy_value_t<std::tuple<First, Second, Rest...>> args_;
-  std::tuple<First, Second, Rest...> args_;
 
 public:
   explicit continuable_box(
-      continuable_base<Data,
+      continuable_base<Data, identity<First, Second, Rest...>>&& continuable)
-                       hints::signature_hint_tag<First, Second, Rest...>>&&
+    : continuable_(std::move(continuable)) {}
-          continuable)
+
-      : continuable_(std::move(continuable)) {
+  auto const& peek() const {
+    return continuable_;
   }
 
-  continuable_base<Data, hints::signature_hint_tag<First, Second, Rest...>>&&
+  auto&& fetch() {
-  fetch() {
     return std::move(continuable_);
   }
 
@@ -130,9 +155,13 @@ public:
   }
 
   auto unbox() && {
-    return traits::unpack(std::move(args_), [](auto&&... args) {
+    return traits::unpack(
-      return spread_this(std::forward<decltype(args)>(args)...);
+        [](auto&&... args) {
-    });
+          return spread_this(std::forward<decltype(args)>(args)...);
+        },
+        unpack_lazy(
+            std::is_default_constructible<std::tuple<First, Second, Rest...>>{},
+            std::move(args_)));
   }
 };
 
@@ -181,29 +210,41 @@ constexpr auto unbox_continuables(Args&&... args) {
 
 namespace detail {
 template <typename Callback, typename Data>
-void finalize_impl(traits::identity<void>, Callback&& callback, Data&&) {
+constexpr auto finalize_impl(identity<void>, Callback&& callback, Data&&) {
-  std::forward<Callback>(callback)();
+  return std::forward<Callback>(callback)();
 }
 template <typename... Args, typename Callback, typename Data>
-void finalize_impl(traits::identity<std::tuple<Args...>>, Callback&& callback,
+constexpr auto finalize_impl(identity<std::tuple<Args...>>, Callback&& callback,
-                   Data&& data) {
+                             Data&& data) {
   // Call the final callback with the cleaned result
-  traits::unpack(unbox_continuables(std::forward<Data>(data)),
+  return traits::unpack(std::forward<Callback>(callback),
-                 std::forward<Callback>(callback));
+                        unbox_continuables(std::forward<Data>(data)));
 }
+
+struct hint_mapper {
+  template <typename... T>
+  constexpr auto operator()(T...) -> identity<T...> {
+    return {};
+  }
+};
 } // namespace detail
 
 template <typename Callback, typename Data>
-void finalize_data(Callback&& callback, Data&& data) {
+constexpr auto finalize_data(Callback&& callback, Data&& data) {
   using result_t = decltype(unbox_continuables(std::forward<Data>(data)));
   // Guard the final result against void
-  return detail::finalize_impl(traits::identity<std::decay_t<result_t>>{},
+  return detail::finalize_impl(identity<std::decay_t<result_t>>{},
                                std::forward<Callback>(callback),
                                std::forward<Data>(data));
 }
-} // namespace remapping
+
-} // namespace composition
+template <typename Data>
+constexpr auto hint_of_data() {
+  return decltype(finalize_data(detail::hint_mapper{}, std::declval<Data>())){};
+}
+} // namespace aggregated
+} // namespace connection
 } // namespace detail
 } // namespace cti
 
-#endif // CONTINUABLE_DETAIL_COMPOSITION_REMAPPING_HPP_INCLUDED
+#endif // CONTINUABLE_DETAIL_CONNECTION_REMAPPING_HPP_INCLUDED

include/continuable/detail/connection/connection-all.hpp

@@ -0,0 +1,198 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_CONNECTION_ALL_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_CONNECTION_ALL_HPP_INCLUDED
+
+#include <atomic>
+#include <memory>
+#include <mutex>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+#include <continuable/continuable-primitives.hpp>
+#include <continuable/detail/connection/connection-aggregated.hpp>
+#include <continuable/detail/connection/connection.hpp>
+#include <continuable/detail/core/annotation.hpp>
+#include <continuable/detail/core/base.hpp>
+#include <continuable/detail/core/types.hpp>
+#include <continuable/detail/utility/traits.hpp>
+
+namespace cti {
+namespace detail {
+namespace connection {
+namespace all {
+/// Caches the partial results and invokes the callback when all results
+/// are arrived. This class is thread safe.
+template <typename Callback, typename Result>
+class result_submitter
+    : public std::enable_shared_from_this<result_submitter<Callback, Result>>,
+      public util::non_movable {
+
+  Callback callback_;
+  Result result_;
+
+  std::atomic<std::size_t> left_;
+  std::once_flag flag_;
+
+  // Invokes the callback with the cached result
+  void invoke() {
+    assert((left_ == 0U) && "Expected that the submitter is finished!");
+    std::atomic_thread_fence(std::memory_order_acquire);
+
+    // Call the final callback with the cleaned result
+    std::call_once(flag_, [&] {
+      aggregated::finalize_data(std::move(callback_), std::move(result_));
+    });
+  }
+
+  // Completes one result
+  void complete_one() {
+    assert((left_ > 0U) && "Expected that the submitter isn't finished!");
+
+    auto const current = --left_;
+    if (!current) {
+      invoke();
+    }
+  }
+
+  template <typename Box>
+  struct partial_all_callback {
+    Box* box;
+    std::shared_ptr<result_submitter> me;
+
+    template <typename... Args>
+    void operator()(Args&&... args) && {
+
+      // Assign the result to the target
+      box->assign(std::forward<decltype(args)>(args)...);
+
+      // Complete one result
+      me->complete_one();
+    }
+
+    template <typename... PartialArgs>
+    void operator()(exception_arg_t tag, exception_t exception) && {
+      // We never complete the connection, but we forward the first error
+      // which was raised.
+      std::call_once(me->flag_, std::move(me->callback_), tag,
+                     std::move(exception));
+    }
+  };
+
+public:
+  explicit result_submitter(Callback callback, Result&& result)
+      : callback_(std::move(callback)), result_(std::move(result)), left_(1) {
+  }
+
+  /// Creates a submitter which submits it's result into the storage
+  template <typename Box>
+  auto create_callback(Box* box) {
+    left_.fetch_add(1, std::memory_order_seq_cst);
+    return partial_all_callback<std::decay_t<Box>>{box,
+                                                   this->shared_from_this()};
+  }
+
+  /// Initially the counter is created with an initial count of 1 in order
+  /// to prevent that the connection is finished before all callbacks
+  /// were registered.
+  void accept() {
+    complete_one();
+  }
+
+  constexpr auto& head() noexcept {
+    return result_;
+  }
+};
+
+template <typename Submitter>
+struct continuable_dispatcher {
+  std::shared_ptr<Submitter>& submitter;
+
+  template <typename Box, std::enable_if_t<aggregated::is_continuable_box<
+                              std::decay_t<Box>>::value>* = nullptr>
+  void operator()(Box&& box) const {
+    // Retrieve a callback from the submitter and attach it to the continuable
+    box.fetch().next(submitter->create_callback(std::addressof(box))).done();
+  }
+};
+} // namespace all
+
+struct connection_strategy_all_tag {};
+template <>
+struct is_connection_strategy<connection_strategy_all_tag> // ...
+    : std::true_type {};
+
+/// Finalizes the all logic of a given connection
+template <>
+struct connection_finalizer<connection_strategy_all_tag> {
+  /// Finalizes the all logic of a given connection
+  template <typename Connection>
+  static auto finalize(Connection&& connection, util::ownership ownership) {
+    // Create the target result from the connection
+    auto res =
+        aggregated::box_continuables(std::forward<Connection>(connection));
+
+    auto signature = aggregated::hint_of_data<decltype(res)>();
+
+    return base::attorney::create_from(
+        [res = std::move(res)](auto&& callback) mutable {
+          using submitter_t =
+              all::result_submitter<std::decay_t<decltype(callback)>,
+                                    std::decay_t<decltype(res)>>;
+
+          // Create the shared state which holds the result
+          // and the final callback
+          auto state = std::make_shared<submitter_t>(
+              std::forward<decltype(callback)>(callback), std::move(res));
+
+          // Dispatch the continuables and store its partial result
+          // in the whole result
+          traverse_pack(all::continuable_dispatcher<submitter_t>{state},
+                        state->head());
+
+          // Finalize the connection if all results arrived in-place
+          state->accept();
+        },
+        signature, std::move(ownership));
+  }
+};
+} // namespace connection
+
+/// Specialization for a connection annotation
+template <>
+struct annotation_trait<connection::connection_strategy_all_tag>
+    : connection::connection_annotation_trait<
+          connection::connection_strategy_all_tag> {};
+
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_CONNECTION_ALL_HPP_INCLUDED

include/continuable/detail/connection/connection-any.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,15 +21,15 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_DETAIL_COMPOSITION_ANY_HPP_INCLUDED
+#ifndef CONTINUABLE_DETAIL_CONNECTION_ANY_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_COMPOSITION_ANY_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_CONNECTION_ANY_HPP_INCLUDED
 
 #include <atomic>
 #include <memory>
@@ -37,18 +37,18 @@
 #include <tuple>
 #include <type_traits>
 #include <utility>
-
+#include <continuable/continuable-primitives.hpp>
 #include <continuable/continuable-promise-base.hpp>
 #include <continuable/continuable-traverse.hpp>
-#include <continuable/detail/base.hpp>
+#include <continuable/detail/core/annotation.hpp>
-#include <continuable/detail/container-category.hpp>
+#include <continuable/detail/core/base.hpp>
-#include <continuable/detail/hints.hpp>
+#include <continuable/detail/core/types.hpp>
-#include <continuable/detail/traits.hpp>
+#include <continuable/detail/traversal/container-category.hpp>
-#include <continuable/detail/types.hpp>
+#include <continuable/detail/utility/traits.hpp>
 
 namespace cti {
 namespace detail {
-namespace composition {
+namespace connection {
 namespace any {
 /// Invokes the callback with the first arriving result
 template <typename T>
@@ -88,30 +88,30 @@ private:
 
 struct result_deducer {
   template <typename T>
-  static auto deduce_one(std::false_type, traits::identity<T>) {
+  static auto deduce_one(std::false_type, identity<T>) {
     static_assert(traits::fail<T>::value,
                   "Non continuable types except tuple like and homogeneous "
                   "containers aren't allowed inside an any expression!");
   }
   template <typename T>
-  static auto deduce_one(std::true_type, traits::identity<T> id) {
+  static auto deduce_one(std::true_type, identity<T> id) {
-    return hints::hint_of(id);
+    return base::annotation_of(id);
   }
   template <typename T>
   static auto deduce(traversal::container_category_tag<false, false>,
-                     traits::identity<T> id) {
+                     identity<T> id) {
     return deduce_one<T>(base::is_continuable<T>{}, id);
   }
 
   /// Deduce a homogeneous container
   template <bool IsTupleLike, typename T>
   static auto deduce(traversal::container_category_tag<true, IsTupleLike>,
-                     traits::identity<T>) {
+                     identity<T>) {
 
     // Deduce the containing type
     using element_t = std::decay_t<decltype(*std::declval<T>().begin())>;
     return deduce(traversal::container_category_of_t<element_t>{},
-                  traits::identity<element_t>{});
+                  identity<element_t>{});
   }
 
   template <typename First, typename... T>
@@ -125,19 +125,18 @@ struct result_deducer {
 
   template <std::size_t... I, typename T>
   static auto deduce_tuple_like(std::integer_sequence<std::size_t, I...>,
-                                traits::identity<T>) {
+                                identity<T>) {
 
     return deduce_same_hints(deduce(
         traversal::container_category_of_t<
             std::decay_t<decltype(std::get<I>(std::declval<T>()))>>{},
-        traits::identity<
+        identity<std::decay_t<decltype(std::get<I>(std::declval<T>()))>>{})...);
-            std::decay_t<decltype(std::get<I>(std::declval<T>()))>>{})...);
   }
 
   /// Traverse tuple like container
   template <typename T>
   static auto deduce(traversal::container_category_tag<false, true>,
-                     traits::identity<T> id) {
+                     identity<T> id) {
 
     constexpr auto const size = std::tuple_size<T>::value;
     return deduce_tuple_like(std::make_index_sequence<size>{}, id);
@@ -151,7 +150,7 @@ struct continuable_dispatcher {
   template <typename Continuable,
             std::enable_if_t<base::is_continuable<
                 std::decay_t<Continuable>>::value>* = nullptr>
-  void operator()(Continuable&& continuable) const {
+  void operator()(Continuable&& continuable) {
     // Retrieve a callback from the submitter and attach it to the continuable
     std::forward<Continuable>(continuable)
         .next(submitter->create_callback())
@@ -160,36 +159,46 @@ struct continuable_dispatcher {
 };
 } // namespace any
 
-/// Finalizes the any logic of a given composition
+struct connection_strategy_any_tag {};
 template <>
-struct composition_finalizer<composition_strategy_any_tag> {
+struct is_connection_strategy<connection_strategy_any_tag> // ...
-  template <typename Composition>
+    : std::true_type {};
-  static constexpr auto hint() {
-    return decltype(any::result_deducer::deduce(
-        traversal::container_category_of_t<std::decay_t<Composition>>{},
-        traits::identity<std::decay_t<Composition>>{})){};
-  }
 
-  template <typename Composition>
+/// Finalizes the any logic of a given connection
-  static auto finalize(Composition&& composition) {
+template <>
-    return [composition = std::forward<Composition>(composition)](
+struct connection_finalizer<connection_strategy_any_tag> {
-        auto&& callback) mutable {
+  template <typename Connection>
+  static auto finalize(Connection&& connection, util::ownership ownership) {
+    constexpr auto const signature = decltype(any::result_deducer::deduce(
+        traversal::container_category_of_t<std::decay_t<Connection>>{},
+        identity<std::decay_t<Connection>>{})){};
 
-      using submitter_t =
+    return base::attorney::create_from(
-          any::any_result_submitter<std::decay_t<decltype(callback)>>;
+        [connection =
+             std::forward<Connection>(connection)](auto&& callback) mutable {
+          using submitter_t =
+              any::any_result_submitter<std::decay_t<decltype(callback)>>;
 
-      // Create the submitter which calls the given callback once at the
+          // Create the submitter which calls the given callback once at the
-      // first callback invocation.
+          // first callback invocation.
-      auto submitter = std::make_shared<submitter_t>(
+          auto submitter = std::make_shared<submitter_t>(
-          std::forward<decltype(callback)>(callback));
+              std::forward<decltype(callback)>(callback));
 
-      traverse_pack(any::continuable_dispatcher<submitter_t>{submitter},
+          traverse_pack(any::continuable_dispatcher<submitter_t>{submitter},
-                    std::move(composition));
+                        std::move(connection));
-    };
+        },
+        signature, std::move(ownership));
   }
 };
-} // namespace composition
+} // namespace connection
+
+/// Specialization for a connection annotation
+template <>
+struct annotation_trait<connection::connection_strategy_any_tag>
+    : connection::connection_annotation_trait<
+          connection::connection_strategy_any_tag> {};
+
 } // namespace detail
 } // namespace cti
 
-#endif // CONTINUABLE_DETAIL_COMPOSITION_ANY_HPP_INCLUDED
+#endif // CONTINUABLE_DETAIL_CONNECTION_ANY_HPP_INCLUDED

include/continuable/detail/connection/connection-seq.hpp

@@ -0,0 +1,183 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_CONNECTION_SEQ_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_CONNECTION_SEQ_HPP_INCLUDED
+
+#include <cassert>
+#include <memory>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+#include <continuable/continuable-primitives.hpp>
+#include <continuable/continuable-traverse-async.hpp>
+#include <continuable/detail/connection/connection-aggregated.hpp>
+#include <continuable/detail/core/base.hpp>
+#include <continuable/detail/utility/traits.hpp>
+#include <continuable/detail/utility/util.hpp>
+
+namespace cti {
+namespace detail {
+namespace connection {
+namespace seq {
+/// Connects the left and the right continuable to a sequence
+///
+/// \note This is implemented in an eager way because we would not gain
+///       any profit from chaining sequences lazily.
+template <typename Left, typename Right>
+auto sequential_connect(Left&& left, Right&& right) {
+  left.freeze(right.is_frozen());
+  right.freeze();
+
+  return std::forward<Left>(left).then(
+      [right = std::forward<Right>(right)](auto&&... args) mutable {
+        return std::move(right).then(
+            [previous = std::make_tuple(std::forward<decltype(args)>(args)...)](
+                auto&&... args) mutable {
+              return std::tuple_cat(
+                  std::move(previous),
+                  std::make_tuple(std::forward<decltype(args)>(args)...));
+            });
+      });
+}
+
+template <typename Callback, typename Box>
+struct sequential_dispatch_data {
+  Callback callback;
+  Box box;
+};
+
+template <typename Data>
+class sequential_dispatch_visitor
+    : public std::enable_shared_from_this<sequential_dispatch_visitor<Data>>,
+      public util::non_movable {
+
+  Data data_;
+
+public:
+  explicit sequential_dispatch_visitor(Data&& data) : data_(std::move(data)) {
+  }
+
+  virtual ~sequential_dispatch_visitor() = default;
+
+  /// Returns the pack that should be traversed
+  auto& head() {
+    return data_.box;
+  }
+
+  template <typename Box, std::enable_if_t<aggregated::is_continuable_box<
+                              std::decay_t<Box>>::value>* = nullptr>
+  bool operator()(async_traverse_visit_tag, Box&& box) {
+    if (base::attorney::is_ready(box.peek())) {
+      // The result can be resolved directly
+      traits::unpack(
+          [&](auto&&... args) mutable {
+            box.assign(std::forward<decltype(args)>(args)...);
+          },
+          base::attorney::query(box.fetch()));
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  template <typename Box, typename N>
+  void operator()(async_traverse_detach_tag, Box&& box, N&& next) {
+    box.fetch()
+        .then([box = std::addressof(box),
+               next = std::forward<N>(next)](auto&&... args) mutable {
+          // Assign the result to the target
+          box->assign(std::forward<decltype(args)>(args)...);
+
+          // Continue the asynchronous sequential traversal
+          next();
+        })
+        .fail([me = this->shared_from_this()](exception_t exception) {
+          // Abort the traversal when an error occurred
+          std::move(me->data_.callback)(exception_arg_t{},
+                                        std::move(exception));
+        })
+        .done();
+  }
+
+  template <typename T>
+  void operator()(async_traverse_complete_tag, T&& /*pack*/) {
+    return aggregated::finalize_data(std::move(data_.callback),
+                                     std::move(data_.box));
+  }
+};
+} // namespace seq
+
+struct connection_strategy_seq_tag {};
+template <>
+struct is_connection_strategy<connection_strategy_seq_tag> // ...
+    : std::true_type {};
+
+/// Finalizes the seq logic of a given connection
+template <>
+struct connection_finalizer<connection_strategy_seq_tag> {
+  /// Finalizes the all logic of a given connection
+  template <typename Connection>
+  static auto finalize(Connection&& connection, util::ownership ownership) {
+
+    auto res =
+        aggregated::box_continuables(std::forward<Connection>(connection));
+
+    auto signature = aggregated::hint_of_data<decltype(res)>();
+
+    return base::attorney::create_from(
+        [res = std::move(res)](auto&& callback) mutable {
+          // The data from which the visitor is constructed in-place
+          using data_t =
+              seq::sequential_dispatch_data<std::decay_t<decltype(callback)>,
+                                            std::decay_t<decltype(res)>>;
+
+          // The visitor type
+          using visitor_t = seq::sequential_dispatch_visitor<data_t>;
+
+          traverse_pack_async(async_traverse_in_place_tag<visitor_t>{},
+                              data_t{std::forward<decltype(callback)>(callback),
+                                     std::move(res)});
+        },
+        signature, std::move(ownership));
+  }
+};
+} // namespace connection
+
+/// Specialization for a connection annotation
+template <>
+struct annotation_trait<connection::connection_strategy_seq_tag>
+    : connection::connection_annotation_trait<
+          connection::connection_strategy_seq_tag> {};
+
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_CONNECTION_SEQ_HPP_INCLUDED

include/continuable/detail/connection/connection.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,55 +21,41 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_DETAIL_COMPOSITION_HPP_INCLUDED
+#ifndef CONTINUABLE_DETAIL_CONNECTION_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_COMPOSITION_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_CONNECTION_HPP_INCLUDED
 
 #include <cassert>
 #include <tuple>
 #include <type_traits>
 #include <utility>
-
 #include <continuable/continuable-traverse.hpp>
-#include <continuable/detail/base.hpp>
+#include <continuable/detail/core/base.hpp>
-#include <continuable/detail/traits.hpp>
+#include <continuable/detail/core/types.hpp>
-#include <continuable/detail/types.hpp>
+#include <continuable/detail/utility/traits.hpp>
-#include <continuable/detail/util.hpp>
+#include <continuable/detail/utility/util.hpp>
 
 namespace cti {
 namespace detail {
-/// The namespace `composition` offers methods to chain continuations together
+/// The namespace `connection` offers methods to chain continuations together
 /// with `all`, `any` or `seq` logic.
-namespace composition {
+namespace connection {
-struct composition_strategy_all_tag {};
-struct composition_strategy_any_tag {};
-struct composition_strategy_seq_tag {};
-
 template <typename T>
-struct is_composition_strategy // ...
+struct is_connection_strategy // ...
     : std::false_type {};
-template <>
-struct is_composition_strategy<composition_strategy_all_tag> // ...
-    : std::true_type {};
-template <>
-struct is_composition_strategy<composition_strategy_any_tag> // ...
-    : std::true_type {};
-template <>
-struct is_composition_strategy<composition_strategy_seq_tag> // ...
-    : std::true_type {};
 
-/// Adds the given continuation tuple to the left composition
+/// Adds the given continuation tuple to the left connection
 template <typename... LeftArgs, typename... RightArgs>
-auto chain_composition(std::tuple<LeftArgs...> leftPack,
+auto chain_connection(std::tuple<LeftArgs...> leftPack,
-                       std::tuple<RightArgs...> rightPack) {
+                      std::tuple<RightArgs...> rightPack) {
 
-  return traits::merge(std::move(leftPack), std::move(rightPack));
+  return std::tuple_cat(std::move(leftPack), std::move(rightPack));
 }
 
 /// Normalizes a continuation to a tuple holding an arbitrary count of
@@ -80,7 +66,7 @@ auto chain_composition(std::tuple<LeftArgs...> leftPack,
 ///   -> make a tuple containing the continuable as only element
 template <
     typename Strategy, typename Data, typename Annotation,
-    std::enable_if_t<!is_composition_strategy<Annotation>::value>* = nullptr>
+    std::enable_if_t<!is_connection_strategy<Annotation>::value>* = nullptr>
 auto normalize(Strategy /*strategy*/,
                continuable_base<Data, Annotation>&& continuation) {
 
@@ -91,13 +77,13 @@ auto normalize(Strategy /*strategy*/,
 ///   -> materialize it
 template <
     typename Strategy, typename Data, typename Annotation,
-    std::enable_if_t<is_composition_strategy<Annotation>::value>* = nullptr>
+    std::enable_if_t<is_connection_strategy<Annotation>::value>* = nullptr>
 auto normalize(Strategy /*strategy*/,
                continuable_base<Data, Annotation>&& continuation) {
 
   // If the right continuation is a different strategy materialize it
   // in order to keep the precedence in cases where: `c1 && (c2 || c3)`.
-  return std::make_tuple(base::attorney::materialize(std::move(continuation)));
+  return std::make_tuple(std::move(continuation).finish());
 }
 /// - The continuable is inside the current strategy state:
 ///   -> return the data of the tuple
@@ -106,7 +92,7 @@ auto normalize(Strategy /*strategy*/,
                continuable_base<Data, Strategy>&& continuation) {
 
   // If we are in the given strategy we can just use the data of the continuable
-  return base::attorney::consume_data(std::move(continuation));
+  return base::attorney::consume(std::move(continuation));
 }
 
 /// Entry function for connecting two continuables with a given strategy.
@@ -123,53 +109,39 @@ auto connect(Strategy strategy, continuable_base<LData, LAnnotation>&& left,
 
   // Make the new data which consists of a tuple containing
   // all connected continuables.
-  auto data = chain_composition(normalize(strategy, std::move(left)),
+  auto data = chain_connection(normalize(strategy, std::move(left)),
-                                normalize(strategy, std::move(right)));
+                               normalize(strategy, std::move(right)));
 
   // Return a new continuable containing the tuple and holding
   // the current strategy as annotation.
-  return base::attorney::create(std::move(data), strategy, ownership_);
+  return base::attorney::create_from_raw(std::move(data), strategy, ownership_);
 }
 
 /// All strategies should specialize this class in order to provide:
 /// - A finalize static method that creates the callable object which
-///   is invoked with the callback to call when the composition is finished.
+///   is invoked with the callback to call when the connection is finished.
 /// - A static method hint that returns the new signature hint.
 template <typename Strategy>
-struct composition_finalizer;
+struct connection_finalizer;
 
-/// Finalizes the connection logic of a given composition
+template <typename Strategy>
-template <typename Data, typename Strategy>
+struct connection_annotation_trait {
-auto finalize_composition(continuable_base<Data, Strategy>&& continuation) {
+  /// Finalizes the connection logic of a given connection
-  using finalizer = composition_finalizer<Strategy>;
+  template <typename Continuable>
+  static auto finish(Continuable&& continuable) {
+    using finalizer = connection_finalizer<Strategy>;
 
-  util::ownership ownership = base::attorney::ownership_of(continuation);
+    util::ownership ownership = base::attorney::ownership_of(continuable);
-  auto composition = base::attorney::consume_data(std::move(continuation));
+    auto connection =
+        base::attorney::consume(std::forward<Continuable>(continuable));
 
-  // Retrieve the new signature hint
+    // Return a new continuable which
-  constexpr auto const signature =
+    return finalizer::finalize(std::move(connection), std::move(ownership));
-      finalizer::template hint<decltype(composition)>();
-
-  // Return a new continuable which
-  return base::attorney::create(finalizer::finalize(std::move(composition)),
-                                signature, std::move(ownership));
-}
-
-/// A base class from which the continuable may inherit in order to
-/// provide a materializer method which will finalize an oustanding strategy.
-template <typename Continuable, typename = void>
-struct materializer {
-  static constexpr auto&& apply(Continuable&& continuable) {
-    return std::move(continuable);
   }
-};
-template <typename Data, typename Strategy>
-struct materializer<
-    continuable_base<Data, Strategy>,
-    std::enable_if_t<is_composition_strategy<Strategy>::value>> {
 
-  static constexpr auto apply(continuable_base<Data, Strategy>&& continuable) {
+  template <typename Continuable>
-    return finalize_composition(std::move(continuable));
+  static bool is_ready(Continuable const& /*continuable*/) noexcept {
+    return false;
   }
 };
 
@@ -199,13 +171,13 @@ public:
 
     // Materialize every continuable
     // TODO Actually we would just need to consume the data here
-    return base::attorney::materialize(std::forward<Continuable>(continuable));
+    return std::forward<Continuable>(continuable).finish();
   }
 };
 
 template <typename Strategy, typename... Args>
-auto apply_composition(Strategy, Args&&... args) {
+auto apply_connection(Strategy, Args&&... args) {
-  using finalizer = composition_finalizer<Strategy>;
+  using finalizer = connection_finalizer<Strategy>;
 
   // Freeze every continuable inside the given arguments,
   // and freeze the ownership if one of the continuables
@@ -213,19 +185,13 @@ auto apply_composition(Strategy, Args&&... args) {
   // Additionally test whether every continuable is acquired.
   // Also materialize every continuable.
   util::ownership ownership;
-  auto composition = map_pack(prepare_continuables{ownership},
+  auto connection = map_pack(prepare_continuables{ownership},
-                              std::make_tuple(std::forward<Args>(args)...));
+                             std::make_tuple(std::forward<Args>(args)...));
 
-  // Retrieve the new signature hint
+  return finalizer::finalize(std::move(connection), std::move(ownership));
-  constexpr auto const signature =
-      finalizer::template hint<decltype(composition)>();
-
-  // Return a new continuable which
-  return base::attorney::create(finalizer::finalize(std::move(composition)),
-                                signature, std::move(ownership));
 }
-} // namespace composition
+} // namespace connection
 } // namespace detail
 } // namespace cti
 
-#endif // CONTINUABLE_DETAIL_COMPOSITION_HPP_INCLUDED
+#endif // CONTINUABLE_DETAIL_CONNECTION_HPP_INCLUDED

include/continuable/detail/core/annotation.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,51 +21,33 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_DETAIL_HINTS_HPP_INCLUDED
+#ifndef CONTINUABLE_DETAIL_ANNOTATION_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_HINTS_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_ANNOTATION_HPP_INCLUDED
 
 #include <type_traits>
-
+#include <continuable/detail/core/types.hpp>
-#include <continuable/detail/traits.hpp>
+#include <continuable/detail/utility/traits.hpp>
-#include <continuable/detail/types.hpp>
 
 namespace cti {
 namespace detail {
 namespace hints {
-/// Represents a present signature hint
-template <typename... Args>
-using signature_hint_tag = traits::identity<Args...>;
-
-/// Returns the signature hint of the given continuable
-template <typename Data, typename... Args>
-constexpr auto
-hint_of(traits::identity<continuable_base<Data, signature_hint_tag<Args...>>>) {
-  return hints::signature_hint_tag<Args...>{};
-}
-
 /// Extracts the signature we pass to the internal continuable
 /// from an argument pack as specified by make_continuable.
 ///
 /// This is the overload taking an arbitrary amount of args
 template <typename... HintArgs>
-constexpr auto extract(traits::identity<HintArgs...> hint) {
+struct from_args : std::common_type<signature_arg_t<HintArgs...>> {};
-  return hint;
+template <>
-}
+struct from_args<void> : std::common_type<signature_arg_t<>> {};
-/// \copybrief extract
-///
-/// This is the overload taking a void arg.
-constexpr auto extract(traits::identity<void> /*hint*/) {
-  return traits::identity<>{};
-}
 } // namespace hints
 } // namespace detail
 } // namespace cti
 
-#endif // CONTINUABLE_DETAIL_HINTS_HPP_INCLUDED
+#endif // CONTINUABLE_DETAIL_ANNOTATION_HPP_INCLUDED

include/continuable/detail/core/types.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -31,9 +31,10 @@
 #ifndef CONTINUABLE_DETAIL_TYPES_HPP_INCLUDED
 #define CONTINUABLE_DETAIL_TYPES_HPP_INCLUDED
 
+#include <type_traits>
 #include <utility>
-
 #include <continuable/detail/features.hpp>
+#include <continuable/detail/utility/identity.hpp>
 
 #ifndef CONTINUABLE_WITH_CUSTOM_ERROR_TYPE
 #ifndef CONTINUABLE_WITH_NO_EXCEPTIONS
@@ -51,32 +52,37 @@ namespace detail {
 /// Contains types used globally across the library
 namespace types {
 #ifdef CONTINUABLE_WITH_CUSTOM_ERROR_TYPE
-using error_type = CONTINUABLE_WITH_CUSTOM_ERROR_TYPE;
+using exception_t = CONTINUABLE_WITH_CUSTOM_ERROR_TYPE;
 #else // CONTINUABLE_WITH_CUSTOM_ERROR_TYPE
 #ifndef CONTINUABLE_WITH_NO_EXCEPTIONS
-/// Represents the error type when exceptions are enabled
+/// Represents the exception type when exceptions are enabled
-using error_type = std::exception_ptr;
+using exception_t = std::exception_ptr;
 #else  // CONTINUABLE_WITH_NO_EXCEPTIONS
 /// Represents the error type when exceptions are disabled
-using error_type = std::error_condition;
+using exception_t = std::error_condition;
 #endif // CONTINUABLE_WITH_NO_EXCEPTIONS
 #endif // CONTINUABLE_WITH_CUSTOM_ERROR_TYPE
 
 /// A tag which is used to execute the continuation inside the current thread
 struct this_thread_executor_tag {};
-/// A tag which is used to continue with an error
-struct dispatch_error_tag {};
 
 /// Marks a given callable object as transformation
 template <typename T>
-class transform : T {
+class plain_tag {
+  T value_;
+
 public:
-  explicit transform(T callable) : T(std::move(callable)) {
+  template <typename O, std::enable_if_t<std::is_constructible<
+                            T, std::decay_t<O>>::value>* = nullptr>
+  /* implicit */ plain_tag(O&& value) : value_(std::forward<O>(value)) {
+  }
+  explicit plain_tag(T value) : value_(std::move(value)) {
   }
 
-  using T::operator();
+  T&& consume() && {
+    return std::move(value_);
+  }
 };
-
 } // namespace types
 } // namespace detail
 } // namespace cti

include/continuable/detail/expected.hpp

@@ -1,394 +0,0 @@
-
-/*
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v3.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#ifndef CONTINUABLE_DETAIL_EXPECTED_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_EXPECTED_HPP_INCLUDED
-
-#include <cassert>
-#include <memory>
-#include <type_traits>
-#include <utility>
-
-#include <continuable/detail/hints.hpp>
-#include <continuable/detail/traits.hpp>
-#include <continuable/detail/types.hpp>
-
-namespace cti {
-namespace detail {
-namespace util {
-namespace detail {
-enum class slot_t { empty, value, error };
-
-template <typename T>
-using storage_of_t = //
-    std::aligned_storage_t<
-        (sizeof(types::error_type) > sizeof(T) ? sizeof(types::error_type)
-                                               : sizeof(T)),
-        (alignof(types::error_type) > alignof(T) ? alignof(types::error_type)
-                                                 : alignof(T))>;
-
-template <typename T>
-struct expected_base {
-  storage_of_t<T> storage_;
-  slot_t slot_;
-
-  constexpr expected_base() : slot_(slot_t::empty) {
-  }
-
-  expected_base(expected_base const&) noexcept {
-  }
-  expected_base(expected_base&&) noexcept {
-  }
-  expected_base& operator=(expected_base const&) {
-    return *this;
-  }
-  expected_base& operator=(expected_base&&) {
-    return *this;
-  }
-};
-
-template <typename Base>
-struct expected_move_base {
-  constexpr expected_move_base() = default;
-
-  expected_move_base(expected_move_base const&) = default;
-  explicit expected_move_base(expected_move_base&& right) {
-    Base& me = *static_cast<Base*>(this);
-    Base& other = *static_cast<Base*>(&right);
-    assert(!other.is_empty());
-
-#ifndef _NDEBUG
-    me.set(slot_t::empty);
-#endif
-
-    other.visit([&](auto&& value) {
-      // ...
-      me.init(std::move(value));
-    });
-    me.set(other.get());
-    other.destroy();
-  }
-  expected_move_base& operator=(expected_move_base const&) = default;
-  expected_move_base& operator=(expected_move_base&& right) {
-    Base& me = *static_cast<Base*>(this);
-    Base& other = *static_cast<Base*>(&right);
-    assert(!other.is_empty());
-
-    me.weak_destroy();
-
-    other.visit([&](auto&& value) {
-      // ...
-      me.init(std::move(value));
-    });
-    me.set(other.get());
-    other.destroy();
-    return *this;
-  }
-};
-template <typename Base, bool IsCopyable /*= true*/>
-struct expected_copy_base : expected_move_base<Base> {
-  constexpr expected_copy_base() = default;
-
-  expected_copy_base(expected_copy_base&&) = default;
-  explicit expected_copy_base(expected_copy_base const& right)
-      : expected_move_base<Base>()
-  // TODO noexcept(Base::is_nothrow_move_constructible)
-  {
-    Base& me = *static_cast<Base*>(this);
-    Base const& other = *static_cast<Base const*>(&right);
-    assert(!other.is_empty());
-
-#ifndef _NDEBUG
-    me.set(slot_t::empty);
-#endif
-
-    other.visit([&](auto&& value) {
-      // ...
-      me.init(std::move(value));
-    });
-    me.set(other.get());
-  }
-  expected_copy_base& operator=(expected_copy_base&&) = default;
-  expected_copy_base& operator=(expected_copy_base const& right)
-  // TODO  noexcept(Base::is_nothrow_move_constructible)
-  {
-    Base& me = *static_cast<Base*>(this);
-    Base const& other = *static_cast<Base const*>(&right);
-    assert(!other.is_empty());
-
-    me.weak_destroy();
-
-    other.visit([&](auto&& value) {
-      // ...
-      me.init(std::move(value));
-    });
-    me.set(other.get());
-    return *this;
-  }
-};
-template <typename Base /*, bool IsCopyable = false*/>
-struct expected_copy_base<Base, false> : expected_move_base<Base> {
-  constexpr expected_copy_base() = default;
-
-  expected_copy_base(expected_copy_base const&) = delete;
-  explicit expected_copy_base(expected_copy_base&& right) = default;
-  expected_copy_base& operator=(expected_copy_base const&) = delete;
-  expected_copy_base& operator=(expected_copy_base&& right) = default;
-};
-} // namespace detail
-
-/// A class similar to the one in the expected proposal,
-/// however it is capable of carrying an exception_ptr if
-/// exceptions are used.
-template <typename T>
-class expected
-    : detail::expected_copy_base<
-          expected<T>, std::is_copy_constructible<types::error_type>::value &&
-                           std::is_copy_constructible<T>::value>,
-      detail::expected_base<T> {
-
-  template <typename>
-  friend class expected;
-  template <typename>
-  friend struct detail::expected_move_base;
-  template <typename, bool>
-  friend struct detail::expected_copy_base;
-
-  template <typename V>
-  expected(V&& value, detail::slot_t const slot) {
-    using type = std::decay_t<decltype(value)>;
-    new (&this->storage_) type(std::forward<V>(value));
-    set(slot);
-  }
-
-public:
-  constexpr expected() = default;
-  expected(expected const&) = default;
-  expected(expected&&) = default;
-  expected& operator=(expected const&) = default;
-  expected& operator=(expected&&) = default;
-
-  ~expected() noexcept(
-      std::is_nothrow_destructible<T>::value&&
-          std::is_nothrow_destructible<types::error_type>::value) {
-    weak_destroy();
-  }
-
-  explicit expected(T value) //
-      : expected(std::move(value), detail::slot_t::value) {
-  }
-  explicit expected(types::error_type error) //
-      : expected(std::move(error), detail::slot_t::error) {
-  }
-
-  expected& operator=(T value) {
-    set_value(std::move(value));
-    return *this;
-  }
-  expected& operator=(types::error_type error) {
-    set_exception(std::move(error));
-    return *this;
-  }
-
-  bool is_value() const noexcept {
-    assert(!is_empty());
-    return is(detail::slot_t::value);
-  }
-  bool is_exception() const noexcept {
-    assert(!is_empty());
-    return is(detail::slot_t::error);
-  }
-
-  explicit constexpr operator bool() const noexcept {
-    return is_value();
-  }
-
-  void set_value(T value) {
-    weak_destroy();
-    init(std::move(value));
-    set(detail::slot_t::value);
-  }
-  void set_exception(types::error_type error) {
-    weak_destroy();
-    init(std::move(error));
-    set(detail::slot_t::error);
-  }
-
-  T& get_value() noexcept {
-    assert(is_value());
-    return cast<T>();
-  }
-  T const& get_value() const noexcept {
-    assert(is_value());
-    return cast<T>();
-  }
-  types::error_type& get_exception() noexcept {
-    assert(is_exception());
-    return cast<types::error_type>();
-  }
-  types::error_type const& get_exception() const noexcept {
-    assert(is_exception());
-    return cast<types::error_type>();
-  }
-
-  T& operator*() noexcept {
-    return get_value();
-  }
-  T const& operator*() const noexcept {
-    return get_value();
-  }
-
-private:
-  template <typename V>
-  void visit(V&& visitor) {
-    switch (this->slot_) {
-      case detail::slot_t::value:
-        return std::forward<V>(visitor)(cast<T>());
-      case detail::slot_t::error:
-        return std::forward<V>(visitor)(cast<types::error_type>());
-      default:
-        // We don't visit when there is no value
-        break;
-    }
-  }
-  template <typename V>
-  void visit(V&& visitor) const {
-    switch (this->slot_) {
-      case detail::slot_t::value:
-        return std::forward<V>(visitor)(cast<T>());
-      case detail::slot_t::error:
-        return std::forward<V>(visitor)(cast<types::error_type>());
-      default:
-        // We don't visit when there is no value
-        break;
-    }
-  }
-
-  bool is_empty() const noexcept {
-    return is(detail::slot_t::empty);
-  }
-
-  template <typename V>
-  V& cast() noexcept {
-    assert(!is_empty());
-    return *reinterpret_cast<V*>(&this->storage_);
-  }
-  template <typename V>
-  V const& cast() const noexcept {
-    assert(!is_empty());
-    return *reinterpret_cast<V const*>(&this->storage_);
-  }
-
-  template <typename V>
-  void init(V&& value) {
-    assert(is_empty());
-    using type = std::decay_t<decltype(value)>;
-    new (&this->storage_) type(std::forward<V>(value));
-  }
-  void destroy() {
-    weak_destroy();
-
-#ifdef NDEBUG
-    set(detail::slot_t::empty);
-#endif
-  }
-  void weak_destroy() {
-    visit([&](auto&& value) {
-      using type = std::decay_t<decltype(value)>;
-      value.~type();
-    });
-
-#ifndef NDEBUG
-    set(detail::slot_t::empty);
-#endif
-  }
-  detail::slot_t get() const noexcept {
-    return this->slot_;
-  }
-  bool is(detail::slot_t const slot) const noexcept {
-    return get() == slot;
-  }
-  void set(detail::slot_t const slot) {
-    this->slot_ = slot;
-  }
-};
-
-namespace detail {
-struct void_guard_tag {};
-
-template <typename T>
-struct expected_result_trait;
-template <>
-struct expected_result_trait<traits::identity<>> {
-  using expected_type = expected<void_guard_tag>;
-
-  static constexpr void_guard_tag wrap() noexcept {
-    return {};
-  }
-  static void unwrap(expected_type&& e) {
-    assert(e.is_value());
-    (void)e;
-  }
-};
-template <typename T>
-struct expected_result_trait<traits::identity<T>> {
-  using expected_type = expected<T>;
-
-  static auto wrap(T arg) {
-    return std::move(arg);
-  }
-  static auto unwrap(expected_type&& e) {
-    assert(e.is_value());
-    return std::move(e.get_value());
-  }
-};
-template <typename First, typename Second, typename... Rest>
-struct expected_result_trait<traits::identity<First, Second, Rest...>> {
-  using expected_type = expected<std::tuple<First, Second, Rest...>>;
-
-  static auto wrap(First first, Second second, Rest... rest) {
-    return std::make_tuple(std::move(first), std::move(second),
-                           std::move(rest)...);
-  }
-  static auto unwrap(expected_type&& e) {
-    assert(e.is_value());
-    return std::move(e.get_value());
-  }
-};
-} // namespace detail
-
-template <typename Continuable>
-using expected_result_trait_t = detail::expected_result_trait<decltype(
-    hints::hint_of(traits::identify<Continuable>{}))>;
-} // namespace util
-} // namespace detail
-} // namespace cti
-
-#endif // CONTINUABLE_DETAIL_EXPECTED_HPP_INCLUDED

include/continuable/detail/external/asio.hpp

@@ -0,0 +1,242 @@
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_ASIO_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_ASIO_HPP_INCLUDED
+
+#include <array>
+#include <utility>
+#include <continuable/continuable-base.hpp>
+#include <continuable/detail/core/base.hpp>
+#include <continuable/detail/features.hpp>
+
+#if defined(ASIO_STANDALONE)
+#  include <asio/async_result.hpp>
+#  include <asio/error.hpp>
+#  include <asio/error_code.hpp>
+#  include <asio/version.hpp>
+
+#  if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#    include <asio/system_error.hpp>
+#  endif
+
+#  if (ASIO_VERSION < 101300) // 1.13.0
+#    define CTI_DETAIL_ASIO_HAS_NO_INTEGRATION
+#  elif (ASIO_VERSION < 101600) // 1.16.0 (boost 1.72 baseline)
+#    define CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION
+#  endif
+
+#  define CTI_DETAIL_ASIO_NAMESPACE_BEGIN namespace asio {
+#  define CTI_DETAIL_ASIO_NAMESPACE_END }
+#else
+#  include <boost/asio/async_result.hpp>
+#  include <boost/asio/error.hpp>
+#  include <boost/system/error_code.hpp>
+#  include <boost/version.hpp>
+
+#  if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#    include <boost/system/system_error.hpp>
+#  endif
+
+#  if (BOOST_VERSION < 107000) // 1.70
+#    define CTI_DETAIL_ASIO_HAS_NO_INTEGRATION
+#  elif (BOOST_VERSION < 107200) // 1.72
+#    define CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION
+#  endif
+
+#  define CTI_DETAIL_ASIO_NAMESPACE_BEGIN                                      \
+    namespace boost {                                                          \
+    namespace asio {
+#  define CTI_DETAIL_ASIO_NAMESPACE_END                                        \
+    }                                                                          \
+    }
+#endif
+
+#if defined(CTI_DETAIL_ASIO_HAS_NO_INTEGRATION)
+#  error "First-class ASIO support for continuable requires the form of "\
+  "`async_result` with an `initiate` static member function, which was added " \
+  "in standalone ASIO 1.13.0 and Boost ASIO 1.70. Older versions can be " \
+  "integrated manually with `cti::promisify`."
+#endif
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#  include <exception>
+#endif
+
+namespace cti {
+namespace detail {
+namespace asio {
+
+#if defined(ASIO_STANDALONE)
+using error_code_t = ::asio::error_code;
+using basic_errors_t = ::asio::error::basic_errors;
+
+#  if defined(CONTINUABLE_HAS_EXCEPTIONS)
+using system_error_t = ::asio::system_error;
+#  endif
+#else
+using error_code_t = ::boost::system::error_code;
+using basic_errors_t = ::boost::asio::error::basic_errors;
+
+#  if defined(CONTINUABLE_HAS_EXCEPTIONS)
+using system_error_t = ::boost::system::system_error;
+#  endif
+#endif
+
+template <typename Promise, typename Token>
+class promise_resolver {
+public:
+  explicit promise_resolver(Promise promise, Token token)
+    : promise_(std::move(promise))
+    , token_(std::move(token)) {}
+
+  template <typename... T>
+  void operator()(T&&... args) noexcept {
+    promise_.set_value(std::forward<T>(args)...);
+  }
+
+  template <typename... T>
+  void operator()(error_code_t e, T&&... args) noexcept {
+    if (e) {
+      if (!token_.is_ignored(e)) {
+        if (token_.is_cancellation(e)) {
+          promise_.set_canceled();
+          return;
+        } else {
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+          promise_.set_exception(
+              std::make_exception_ptr(system_error_t(std::move(e))));
+#else
+          promise_.set_exception(exception_t(e.value(), e.category()));
+#endif
+          return;
+        }
+      }
+    }
+    promise_.set_value(std::forward<T>(args)...);
+  }
+
+private:
+  Promise promise_;
+  Token token_;
+};
+
+// Binds `promise` to the first argument of a continuable resolver, giving it
+// the signature of an ASIO handler.
+template <typename Promise, typename Token>
+auto promise_resolver_handler(Promise&& promise, Token&& token) noexcept {
+  return promise_resolver<std::decay_t<Promise>, std::decay_t<Token>>(
+      std::forward<Promise>(promise), std::forward<Token>(token));
+}
+
+// Helper struct wrapping a call to `cti::make_continuable` and, if needed,
+// providing an erased, explicit `return_type` for `async_result`.
+template <typename Signature>
+struct initiate_make_continuable;
+
+template <typename... Args>
+struct initiate_make_continuable<void(Args...)> {
+#if defined(CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION)
+  using erased_return_type = continuable<Args...>;
+#endif
+
+  template <typename Continuation>
+  auto operator()(Continuation&& continuation) {
+    return base::attorney::create_from(std::forward<Continuation>(continuation),
+                                       identity<Args...>{}, util::ownership{});
+  }
+};
+
+template <typename... Args>
+struct initiate_make_continuable<void(error_code_t, Args...)> {
+#if defined(CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION)
+  using erased_return_type = continuable<Args...>;
+#endif
+
+  template <typename Continuation>
+  auto operator()(Continuation&& continuation) {
+    return base::attorney::create_from(std::forward<Continuation>(continuation),
+                                       identity<Args...>{}, util::ownership{});
+  }
+};
+
+template <typename... Args>
+struct initiate_make_continuable<void(error_code_t const&, Args...)>
+  : initiate_make_continuable<void(error_code_t, Args...)> {};
+
+struct map_default {
+  constexpr map_default() noexcept {}
+
+  bool is_cancellation(error_code_t const& ec) const noexcept {
+    // Continuable uses a default constructed exception type to signal
+    // cancellation to the followed asynchronous control flow.
+    return ec == basic_errors_t::operation_aborted;
+  }
+  bool is_ignored(error_code_t const& /*ec*/) const noexcept {
+    return false;
+  }
+};
+
+struct map_none {
+  constexpr map_none() noexcept {}
+
+  bool is_cancellation(error_code_t const& /*ec*/) const noexcept {
+    return false;
+  }
+  bool is_ignored(error_code_t const& /*ec*/) const noexcept {
+    return false;
+  }
+};
+
+template <std::size_t Size>
+class map_ignore {
+public:
+  map_ignore(std::array<basic_errors_t, Size> ignored) noexcept
+    : ignored_(ignored) {}
+
+  bool is_cancellation(error_code_t const& ec) const noexcept {
+    return ec == basic_errors_t::operation_aborted;
+  }
+  bool is_ignored(error_code_t const& ec) const noexcept {
+    for (basic_errors_t ignored : ignored_) {
+      if (ec == ignored) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+private:
+  std::array<basic_errors_t, Size> ignored_;
+};
+} // namespace asio
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_ASIO_HPP_INCLUDED

include/continuable/detail/features.hpp

@@ -1,12 +1,13 @@
+
 /*
 
                         /~` _  _ _|_. _     _ |_ | _
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -20,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -32,19 +33,19 @@
 
 // Defines CONTINUABLE_WITH_NO_EXCEPTIONS when exception support is disabled
 #ifndef CONTINUABLE_WITH_NO_EXCEPTIONS
-#if defined(_MSC_VER)
+#  if defined(_MSC_VER)
-#if !defined(_HAS_EXCEPTIONS) || (_HAS_EXCEPTIONS == 0)
+#    if !defined(_HAS_EXCEPTIONS) || (_HAS_EXCEPTIONS == 0)
-#define CONTINUABLE_WITH_NO_EXCEPTIONS
+#      define CONTINUABLE_WITH_NO_EXCEPTIONS
-#endif
+#    endif
-#elif defined(__clang__)
+#  elif defined(__clang__)
-#if !(__EXCEPTIONS && __has_feature(cxx_exceptions))
+#    if !(__EXCEPTIONS && __has_feature(cxx_exceptions))
-#define CONTINUABLE_WITH_NO_EXCEPTIONS
+#      define CONTINUABLE_WITH_NO_EXCEPTIONS
-#endif
+#    endif
-#elif defined(__GNUC__)
+#  elif defined(__GNUC__)
-#if !__EXCEPTIONS
+#    if !__EXCEPTIONS
-#define CONTINUABLE_WITH_NO_EXCEPTIONS
+#      define CONTINUABLE_WITH_NO_EXCEPTIONS
-#endif
+#    endif
-#endif
+#  endif
 #endif // CONTINUABLE_WITH_NO_EXCEPTIONS
 
 // clang-format off
@@ -54,8 +55,11 @@
   #define CONTINUABLE_HAS_CXX17_CONSTEXPR_IF
   #define CONTINUABLE_HAS_CXX17_DISJUNCTION
   #define CONTINUABLE_HAS_CXX17_CONJUNCTION
+  #define CONTINUABLE_HAS_CXX17_VOID_T
 #else
   // Generic feature detection based on __has_feature
+  // and other preprocessor definitions based on:
+  // http://en.cppreference.com/w/User:D41D8CD98F/feature_testing_macros
   #if defined(__has_feature)
     #if !defined(CONTINUABLE_HAS_CXX17_CONSTEXPR_IF) &&                        \
         __has_feature(cxx_if_constexpr)
@@ -74,12 +78,49 @@
       (__cpp_lib_experimental_logical_traits >= 201511)
     #define CONTINUABLE_HAS_CXX17_CONJUNCTION
   #endif
+
+  #if !defined(CONTINUABLE_HAS_CXX17_VOID_T) &&                                \
+      defined(__cpp_lib_void_t) &&                                             \
+      (__cpp_lib_void_t >= 201411)
+    #define CONTINUABLE_HAS_CXX17_VOID_T
+  #endif
 #endif
 
-/// Usually this is enabled by the CMake project
+// Automatically detects support for coroutines.
-#if !defined(CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE) &&                        \
+// Parts of this detection mechanism were adapted from boost::asio,
-    defined(__cpp_coroutines) && (__cpp_coroutines >= 201707)
+// with support added for experimental coroutines.
-  #define CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE
+#if !defined(CONTINUABLE_HAS_DISABLED_COROUTINE) \
+ && !defined(CONTINUABLE_HAS_COROUTINE)
+  /// Define CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE when
+  /// CONTINUABLE_WITH_EXPERIMENTAL_COROUTINE is defined.
+  #if defined(CONTINUABLE_WITH_EXPERIMENTAL_COROUTINE)
+    #define CONTINUABLE_HAS_COROUTINE 1
+  #elif defined(CONTINUABLE_WITH_COROUTINE)
+    #define CONTINUABLE_HAS_COROUTINE 1
+    #define CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE 1
+  #elif defined(_MSC_VER) // Visual Studio
+    #if (_MSC_VER >= 1928) && (_MSVC_LANG >= 201705)
+      #define CONTINUABLE_HAS_COROUTINE 1
+    #elif _MSC_FULL_VER >= 190023506
+      #if defined(_RESUMABLE_FUNCTIONS_SUPPORTED)
+        #define CONTINUABLE_HAS_COROUTINE 1
+        #define CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE 1
+      #endif // defined(_RESUMABLE_FUNCTIONS_SUPPORTED)
+    #endif // _MSC_FULL_VER >= 190023506
+  #elif defined(__clang__) // Clang
+    #if defined(__cpp_coroutines) && (__cpp_coroutines >= 201703L)
+      #define CONTINUABLE_HAS_COROUTINE 1
+      #if defined(_LIBCPP_EXPERIMENTAL_COROUTINE)
+        #define CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE 1
+      #endif
+    #endif // defined(__cpp_coroutines) && (__cpp_coroutines >= 201703L)
+  #elif defined(__GNUC__) // GCC
+    #if (__cplusplus >= 201709) && (__cpp_impl_coroutine >= 201902)
+      #if __has_include(<coroutine>)
+        #define CONTINUABLE_HAS_COROUTINE 1
+      #endif // __has_include(<coroutine>)
+    #endif // (__cplusplus >= 201709) && (__cpp_impl_coroutine >= 201902)
+  #endif
 #endif
 
 /// Define CONTINUABLE_HAS_EXCEPTIONS when exceptions are used
@@ -89,6 +130,18 @@
 #else
   #undef CONTINUABLE_HAS_EXCEPTIONS
 #endif
+
+/// Define CONTINUABLE_HAS_IMMEDIATE_TYPES when either
+/// - CONTINUABLE_WITH_IMMEDIATE_TYPES is defined
+/// - Building in release mode (NDEBUG is defined)
+///
+/// Build error messages will become more readable in debug mode while
+/// we don't suffer any runtime penalty in release.
+#if defined(CONTINUABLE_WITH_IMMEDIATE_TYPES) || defined(NDEBUG)
+  #define CONTINUABLE_HAS_IMMEDIATE_TYPES 1
+#else
+  #undef CONTINUABLE_HAS_IMMEDIATE_TYPES
+#endif
 // clang-format on
 
 #endif // CONTINUABLE_DETAIL_FEATURES_HPP_INCLUDED

include/continuable/detail/operations/async.hpp

@@ -0,0 +1,80 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_OPERATIONS_ASYNC_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_OPERATIONS_ASYNC_HPP_INCLUDED
+
+#include <continuable/continuable-base.hpp>
+#include <continuable/detail/core/annotation.hpp>
+#include <continuable/detail/core/base.hpp>
+#include <continuable/detail/utility/identity.hpp>
+
+namespace cti {
+namespace detail {
+namespace operations {
+template <typename Callable, typename Executor, typename... Args>
+auto async(Callable&& callable, Executor&& executor, Args&&... args) {
+  using result_t =
+      decltype(util::invoke(std::forward<decltype(callable)>(callable),
+                            std::forward<decltype(args)>(args)...));
+
+  constexpr auto hint =
+      decltype(base::decoration::invoker_of(identity<result_t>{}))::hint();
+
+  auto continuation = [callable = std::forward<decltype(callable)>(callable),
+                       executor = std::forward<decltype(executor)>(executor),
+                       args = std::make_tuple(std::forward<decltype(args)>(
+                           args)...)](auto&& promise) mutable {
+    auto invoker = base::decoration::invoker_of(identity<result_t>{});
+
+    using promise_t = decltype(promise);
+
+    // Invoke the callback
+    traits::unpack(
+        [&](auto&&... args) mutable {
+          // Invoke the promise through the dedicated invoker
+          // and through the given executor
+          base::on_executor(std::move(executor), std::move(invoker),
+                            std::move(callable),
+                            std::forward<promise_t>(promise),
+                            std::forward<decltype(args)>(args)...);
+        },
+        std::move(args));
+  };
+
+  return base::attorney::create_from(std::move(continuation), //
+                                     hint, util::ownership{});
+}
+} // namespace operations
+
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_OPERATIONS_ASYNC_HPP_INCLUDED

include/continuable/detail/operations/loop.hpp

@@ -0,0 +1,180 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_OPERATIONS_LOOP_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_OPERATIONS_LOOP_HPP_INCLUDED
+
+#include <cassert>
+#include <memory>
+#include <tuple>
+#include <type_traits>
+#include <continuable/continuable-base.hpp>
+#include <continuable/continuable-result.hpp>
+#include <continuable/detail/features.hpp>
+#include <continuable/detail/utility/traits.hpp>
+#include <continuable/detail/utility/util.hpp>
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#include <exception>
+#endif // CONTINUABLE_HAS_EXCEPTIONS
+
+namespace cti {
+namespace detail {
+template <typename T>
+struct loop_trait {
+  static_assert(!std::is_same<T, T>::value,
+                "The callable passed to cti::loop must always return a "
+                "cti::continuable_base which resolves to a cti::result.");
+};
+
+template <typename... Args>
+struct loop_trait<identity<result<Args...>>> {
+  template <typename Callable>
+  static auto make(Callable&& callable) {
+    return make_continuable<Args...>(std::forward<Callable>(callable));
+  }
+};
+template <>
+struct loop_trait<identity<result<>>> {
+  template <typename Callable>
+  static auto make(Callable&& callable) {
+    return make_continuable<void>(std::forward<Callable>(callable));
+  }
+};
+
+namespace operations {
+template <typename Promise, typename Callable, typename ArgsTuple>
+class loop_frame : public std::enable_shared_from_this<
+                       loop_frame<Promise, Callable, ArgsTuple>> {
+  Promise promise_;
+  Callable callable_;
+  ArgsTuple args_;
+
+public:
+  explicit loop_frame(Promise promise, Callable callable, ArgsTuple args)
+      : promise_(std::move(promise)), callable_(std::move(callable)),
+        args_(std::move(args)) {
+  }
+
+  void loop() {
+    // MSVC can't evaluate this inside the lambda capture
+    auto me = this->shared_from_this();
+
+    traits::unpack(
+        [&](auto&&... args) mutable {
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+          try {
+#endif // CONTINUABLE_HAS_EXCEPTIONS
+
+            util::invoke(callable_, std::forward<decltype(args)>(args)...)
+                .next([me = std::move(me)](auto&&... args) {
+                  me->resolve(std::forward<decltype(args)>(args)...);
+                });
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+          } catch (...) {
+            me->resolve(exception_arg_t{}, std::current_exception());
+          }
+#endif // CONTINUABLE_HAS_EXCEPTIONS
+        },
+        args_);
+  }
+
+  template <typename Result>
+  void resolve(Result&& result) {
+    if (result.is_empty()) {
+      loop();
+    } else if (result.is_value()) {
+      traits::unpack(std::move(promise_), std::forward<Result>(result));
+    } else {
+      assert(result.is_exception());
+      std::move(promise_).set_exception(
+          std::forward<Result>(result).get_exception());
+    }
+  }
+
+  void resolve(exception_arg_t, exception_t exception) {
+    promise_.set_exception(std::move(exception));
+  }
+};
+
+template <typename Promise, typename Callable, typename ArgsTuple>
+auto make_loop_frame(Promise&& promise, Callable&& callable,
+                     ArgsTuple&& args_tuple) {
+  using frame_t =
+      loop_frame<traits::unrefcv_t<Promise>, traits::unrefcv_t<Callable>,
+                 traits::unrefcv_t<ArgsTuple>>;
+
+  return std::make_shared<frame_t>(std::forward<Promise>(promise),
+                                   std::forward<Callable>(callable),
+                                   std::forward<ArgsTuple>(args_tuple));
+}
+
+template <typename Callable, typename... Args>
+auto loop(Callable&& callable, Args&&... args) {
+  using invocation_result_t =
+      decltype(util::invoke(callable, args...).finish());
+
+  auto constexpr hint = base::annotation_of(identify<invocation_result_t>{});
+
+  using trait_t = loop_trait<std::remove_const_t<decltype(hint)>>;
+
+  return trait_t::make([callable = std::forward<decltype(callable)>(callable),
+                        args = std::make_tuple(std::forward<decltype(args)>(
+                            args)...)](auto&& promise) mutable {
+    // Do the actual looping
+    auto frame = make_loop_frame(std::forward<decltype(promise)>(promise),
+                                 std::move(callable), std::move(args));
+    frame->loop();
+  });
+}
+
+template <typename Callable, typename Begin, typename End>
+auto make_range_looper(Callable&& callable, Begin&& begin, End&& end) {
+  return [callable = std::forward<Callable>(callable),
+          begin = std::forward<Begin>(begin),
+          end = std::forward<End>(end)]() mutable {
+    return util::invoke(callable, begin)
+        .then([&begin, &end]() mutable -> plain_t<result<>> {
+          // begin and end stays valid over the `then` here
+          if (++begin != end) {
+            return make_plain(result<>::empty());
+          } else {
+            return make_plain(make_result());
+          }
+        });
+  };
+}
+} // namespace operations
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_OPERATIONS_LOOP_HPP_INCLUDED

include/continuable/detail/operations/split.hpp

@@ -0,0 +1,118 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_OPERATIONS_SPLIT_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_OPERATIONS_SPLIT_HPP_INCLUDED
+
+#include <tuple>
+#include <utility>
+#include <continuable/continuable-base.hpp>
+#include <continuable/continuable-traverse.hpp>
+#include <continuable/continuable-types.hpp>
+#include <continuable/detail/utility/traits.hpp>
+
+namespace cti {
+namespace detail {
+namespace operations {
+template <typename T, bool Else, typename = void>
+struct operator_bool_or {
+  template <typename O>
+  static bool get(O&& /*obj*/) noexcept {
+    return Else;
+  }
+};
+template <typename T, bool Else>
+struct operator_bool_or<T, Else,
+                        traits::void_t<decltype(bool(std::declval<T&>()))>> {
+  template <typename O>
+  static bool get(O&& obj) noexcept {
+    return bool(obj);
+  }
+};
+
+template <typename First, typename... Promises>
+class split_promise {
+  First first_;
+  std::tuple<Promises...> promises_;
+
+public:
+  explicit split_promise(First first, Promises... promises)
+      : first_(std::move(first)), promises_(std::move(promises)...) {
+  }
+
+  template <typename... Args>
+  void operator()(Args&&... args) && {
+    traverse_pack(
+        [&](auto&& promise) mutable -> void {
+          using accessor =
+              operator_bool_or<traits::unrefcv_t<decltype(promise)>, true>;
+          if (accessor::get(promise)) {
+            std::forward<decltype(promise)>(promise)(args...);
+          }
+        },
+        std::move(promises_));
+
+    if (operator_bool_or<First, true>::get(first_)) {
+      std::move(first_)(std::forward<Args>(args)...);
+    }
+  }
+
+  template <typename... Args>
+  void set_value(Args... args) noexcept {
+    std::move (*this)(std::move(args)...);
+  }
+
+  void set_exception(exception_t error) noexcept {
+    std::move (*this)(exception_arg_t{}, std::move(error));
+  }
+
+  void set_canceled() noexcept {
+    std::move (*this)(exception_arg_t{}, exception_t{});
+  }
+
+  explicit operator bool() const noexcept {
+    bool is_valid = operator_bool_or<First, true>::get(first_);
+    traverse_pack(
+        [&](auto&& promise) mutable -> void {
+          using accessor =
+              operator_bool_or<traits::unrefcv_t<decltype(promise)>, true>;
+          if (!is_valid && accessor::get(promise)) {
+            is_valid = true;
+          }
+        },
+        promises_);
+    return is_valid;
+  }
+};
+} // namespace operations
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_OPERATIONS_SPLIT_HPP_INCLUDED

include/continuable/detail/other/coroutines.hpp

@@ -0,0 +1,273 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+// Exclude this header when coroutines are not available
+#ifndef CONTINUABLE_DETAIL_AWAITING_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_AWAITING_HPP_INCLUDED
+
+#include <cassert>
+#include <type_traits>
+#include <continuable/continuable-primitives.hpp>
+#include <continuable/continuable-result.hpp>
+#include <continuable/detail/core/annotation.hpp>
+#include <continuable/detail/core/base.hpp>
+#include <continuable/detail/core/types.hpp>
+#include <continuable/detail/features.hpp>
+#include <continuable/detail/utility/traits.hpp>
+#include <continuable/detail/utility/util.hpp>
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#  include <exception>
+#endif // CONTINUABLE_HAS_EXCEPTIONS
+
+#if defined(CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
+#  include <experimental/coroutine>
+#elif defined(CONTINUABLE_HAS_COROUTINE)
+#  include <coroutine>
+#endif
+
+#if defined(CONTINUABLE_HAS_COROUTINE)
+namespace cti {
+namespace detail {
+namespace awaiting {
+/// We import the coroutine handle in our namespace
+#  if defined(CONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
+using std::experimental::coroutine_handle;
+using std::experimental::suspend_never;
+#  else
+using std::coroutine_handle;
+using std::suspend_never;
+#  endif
+
+#  if defined(CONTINUABLE_HAS_EXCEPTIONS)
+class await_canceled_exception : public std::exception {
+public:
+  await_canceled_exception() noexcept = default;
+
+  char const* what() const noexcept override {
+    return "co_await canceled due to cancellation of the continuation";
+  }
+};
+#  endif // CONTINUABLE_HAS_EXCEPTIONS
+
+template <typename T>
+struct result_from_identity;
+template <typename... T>
+struct result_from_identity<identity<T...>> {
+  using result_t = result<T...>;
+};
+
+/// An object which provides the internal buffer and helper methods
+/// for waiting on a continuable in a stackless coroutine.
+template <typename Continuable>
+class awaitable {
+  using hint_t = decltype(base::annotation_of(identify<Continuable>{}));
+  using result_t = typename result_from_identity<hint_t>::result_t;
+
+  /// The continuable which is invoked upon suspension
+  Continuable continuable_;
+  /// A cache which is used to pass the result of the continuation
+  /// to the coroutine.
+  result_t result_;
+  /// Enumeration that represents the suspension state of the awaitable.
+  enum class state : std::uint8_t {
+    suspended,
+    pending,
+    resolved,
+  };
+  /// An atomic that specifies whether the awaitable has suspended or not.
+  /// Allows to perform symmetric transfer on continuables that are
+  /// immediately resolved.
+  std::atomic<state> state_{state::pending};
+
+public:
+  explicit constexpr awaitable(Continuable&& continuable)
+    : continuable_(std::move(continuable)) {
+
+    // If the continuable is ready resolve the result from the
+    // continuable immediately.
+    if (base::attorney::is_ready(continuable_)) {
+      assert(result_.is_empty());
+      result_ = base::attorney::query(std::move(continuable_));
+    }
+  }
+
+  /// Return whether the continuable can provide its result instantly,
+  /// which also means its execution is side-effect free.
+  bool await_ready() const noexcept {
+    return !result_.is_empty();
+  }
+
+  /// Suspend the current context
+  // TODO Convert this to an r-value function once possible
+  bool await_suspend(coroutine_handle<> h) {
+    assert(result_.is_empty());
+    // Forward every result to the current awaitable
+    std::move(continuable_)
+        .next([h, this](auto&&... args) mutable {
+          assert(result_.is_empty());
+          result_ = result_t::from(std::forward<decltype(args)>(args)...);
+
+          // If true, it means that the promise was suspended (i.e., the
+          // awaitable await_suspend method has already returned). That
+          // means we must call the resume coroutine from the continuation
+          // chain.
+          if (state_.exchange(state::resolved, std::memory_order_acq_rel) ==
+              state::suspended) {
+            return h.resume();
+          }
+        })
+        .done();
+
+    return state_.exchange(state::suspended, std::memory_order_acq_rel) !=
+           state::resolved;
+  }
+
+  /// Resume the coroutine represented by the handle
+  typename result_t::value_t await_resume() noexcept(false) {
+    if (result_.is_value()) {
+      // When the result was resolved return it
+      return std::move(result_).get_value();
+    }
+
+    assert(result_.is_exception());
+
+#  if defined(CONTINUABLE_HAS_EXCEPTIONS)
+    if (exception_t e = result_.get_exception()) {
+      std::rethrow_exception(std::move(e));
+    } else {
+      throw await_canceled_exception();
+    }
+#  else  // CONTINUABLE_HAS_EXCEPTIONS
+    // Returning error types from co_await isn't supported!
+    CTI_DETAIL_TRAP();
+#  endif // CONTINUABLE_HAS_EXCEPTIONS
+  }
+};
+
+/// Converts a continuable into an awaitable object as described by
+/// the C++ coroutine TS.
+template <typename T>
+constexpr auto create_awaiter(T&& continuable) {
+  return awaitable<std::decay_t<T>>(std::forward<T>(continuable));
+}
+
+/// This makes it possible to take the coroutine_handle over on suspension
+struct handle_takeover {
+  coroutine_handle<>& handle_;
+
+  bool await_ready() noexcept {
+    return false;
+  }
+
+  void await_suspend(coroutine_handle<> handle) noexcept {
+    handle_ = handle;
+  }
+
+  void await_resume() noexcept {}
+};
+
+/// The type which is passed to the compiler that describes the properties
+/// of a continuable_base used as coroutine promise type.
+template <typename Continuable, typename Promise, typename... Args>
+struct promise_type;
+
+/// Implements the resolving method return_void and return_value accordingly
+template <typename Base>
+struct promise_resolver_base;
+
+template <typename Continuable, typename Promise>
+struct promise_resolver_base<promise_type<Continuable, Promise>> {
+  void return_void() {
+    auto me = static_cast<promise_type<Continuable, Promise>*>(this);
+    me->promise_.set_value();
+  }
+};
+template <typename Continuable, typename Promise, typename T>
+struct promise_resolver_base<promise_type<Continuable, Promise, T>> {
+  void return_value(T value) {
+    auto me = static_cast<promise_type<Continuable, Promise, T>*>(this);
+    me->promise_.set_value(std::move(value));
+  }
+};
+template <typename Continuable, typename Promise, typename... Args>
+struct promise_resolver_base<promise_type<Continuable, Promise, Args...>> {
+  template <typename T>
+  void return_value(T&& tuple_like) {
+    auto me = static_cast<promise_type<Continuable, Promise, Args...>*>(this);
+    traits::unpack(std::move(me->promise_), std::forward<T>(tuple_like));
+  }
+};
+
+template <typename Continuable, typename Promise, typename... Args>
+struct promise_type
+  : promise_resolver_base<promise_type<Continuable, Promise, Args...>> {
+
+  coroutine_handle<> handle_;
+  Promise promise_;
+
+  explicit promise_type() = default;
+
+  Continuable get_return_object() {
+    return [this](auto&& promise) {
+      promise_ = std::forward<decltype(promise)>(promise);
+      handle_.resume();
+    };
+  }
+
+  handle_takeover initial_suspend() {
+    return {handle_};
+  }
+
+  suspend_never final_suspend() noexcept {
+    return {};
+  }
+
+  void unhandled_exception() noexcept {
+#  if defined(CONTINUABLE_HAS_EXCEPTIONS)
+    try {
+      std::rethrow_exception(std::current_exception());
+    } catch (await_canceled_exception const&) {
+      promise_.set_canceled();
+    } catch (...) {
+      promise_.set_exception(std::current_exception());
+    }
+#  else  // CONTINUABLE_HAS_EXCEPTIONS
+    // Returning exception types from a coroutine isn't supported
+    CTI_DETAIL_TRAP();
+#  endif // CONTINUABLE_HAS_EXCEPTIONS
+  }
+};
+} // namespace awaiting
+} // namespace detail
+} // namespace cti
+#endif // defined(CONTINUABLE_HAS_COROUTINE)
+
+#endif // CONTINUABLE_DETAIL_UTIL_HPP_INCLUDED

include/continuable/detail/other/erasure.hpp

@@ -0,0 +1,241 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_ERASURE_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_ERASURE_HPP_INCLUDED
+
+#include <type_traits>
+#include <utility>
+#include <function2/function2.hpp>
+#include <continuable/detail/core/base.hpp>
+#include <continuable/detail/features.hpp>
+#include <continuable/detail/utility/traits.hpp>
+
+namespace cti {
+namespace detail {
+namespace erasure {
+template <typename... Args>
+using callback_erasure_t =
+    fu2::function_base<true, false, fu2::capacity_none, true, false,
+                       void(Args...)&&, void(exception_arg_t, exception_t) &&>;
+
+#ifdef CONTINUABLE_HAS_IMMEDIATE_TYPES
+template <typename... Args>
+using callback = callback_erasure_t<Args...>;
+#else
+template <typename... Args>
+class callback;
+
+template <typename T>
+struct is_callback : std::false_type {};
+template <typename... Args>
+struct is_callback<callback<Args...>> : std::true_type {};
+
+template <typename... Args>
+class callback : public callback_erasure_t<Args...> {
+public:
+  using erasure_t = callback_erasure_t<Args...>;
+  erasure_t erasure_;
+
+  callback() = default;
+  ~callback() = default;
+  callback(callback const&) = delete;
+  callback(callback&&) = default;
+  callback& operator=(callback const&) = delete;
+  callback& operator=(callback&&) = default;
+
+  template <
+      typename T,
+      std::enable_if_t<std::is_convertible<T, erasure_t>::value>* = nullptr,
+      std::enable_if_t<!is_callback<traits::unrefcv_t<T>>::value>* = nullptr>
+  /* implicit */ callback(T&& callable) : erasure_(std::forward<T>(callable)) {
+  }
+
+  template <
+      typename T,
+      std::enable_if_t<std::is_assignable<erasure_t, T>::value>* = nullptr,
+      std::enable_if_t<!is_callback<traits::unrefcv_t<T>>::value>* = nullptr>
+  callback& operator=(T&& callable) {
+    erasure_ = std::forward<T>(callable);
+    return *this;
+  }
+
+  void operator()(Args... args) && noexcept {
+    std::move(erasure_)(std::move(args)...);
+  }
+
+  void operator()(exception_arg_t exception_arg, exception_t exception) &&
+      noexcept {
+    std::move(erasure_)(exception_arg, std::move(exception));
+  }
+
+  explicit operator bool() const noexcept {
+    return bool(erasure_);
+  }
+};
+#endif
+
+using work_erasure_t =
+    fu2::function_base<true, false, fu2::capacity_fixed<32UL>, true, false,
+                       void()&&, void(exception_arg_t, exception_t) &&>;
+
+#ifdef CONTINUABLE_HAS_IMMEDIATE_TYPES
+using work = work_erasure_t;
+#else
+class work;
+
+template <typename T>
+struct is_work : std::false_type {};
+template <>
+struct is_work<work> : std::true_type {};
+
+class work {
+  using erasure_t = work_erasure_t;
+  erasure_t erasure_;
+
+public:
+  work() = default;
+  ~work() = default;
+  work(work const&) = delete;
+  work(work&&) = default;
+  work& operator=(work const&) = delete;
+  work& operator=(work&&) = default;
+
+  template <
+      typename T,
+      std::enable_if_t<std::is_convertible<T, erasure_t>::value>* = nullptr,
+      std::enable_if_t<!is_work<traits::unrefcv_t<T>>::value>* = nullptr>
+  /* implicit */ work(T&& callable) : erasure_(std::forward<T>(callable)) {
+  }
+
+  template <
+      typename T,
+      std::enable_if_t<std::is_assignable<erasure_t, T>::value>* = nullptr,
+      std::enable_if_t<!is_work<traits::unrefcv_t<T>>::value>* = nullptr>
+  work& operator=(T&& callable) {
+    erasure_ = std::forward<T>(callable);
+    return *this;
+  }
+
+  void operator()() && noexcept {
+    std::move(erasure_)();
+  }
+
+  void operator()(exception_arg_t, exception_t exception) && noexcept {
+    std::move(erasure_)(exception_arg_t{}, std::move(exception));
+  }
+
+  explicit operator bool() const noexcept {
+    return bool(erasure_);
+  }
+};
+#endif
+
+template <typename... Args>
+struct continuation_capacity {
+  using type = union {
+    void* pointer_;
+    base::ready_continuation<Args...> continuation_;
+  };
+
+  static constexpr std::size_t capacity = sizeof(type);
+  static constexpr std::size_t alignment = alignof(type);
+};
+
+template <typename... Args>
+using continuation_erasure_t = fu2::function_base<
+    true, false, continuation_capacity<Args...>, true, false,
+    void(promise_base<callback<Args...>, signature_arg_t<Args...>>),
+    bool(is_ready_arg_t) const, result<Args...>(unpack_arg_t)>;
+
+#ifdef CONTINUABLE_HAS_IMMEDIATE_TYPES
+template <typename... Args>
+using continuation = continuation_erasure_t<Args...>;
+#else
+template <typename... Args>
+class continuation;
+
+template <typename T>
+struct is_continuation : std::false_type {};
+template <typename... Args>
+struct is_continuation<continuation<Args...>> : std::true_type {};
+
+template <typename... Args>
+class continuation {
+  using erasure_t = continuation_erasure_t<Args...>;
+  erasure_t erasure_;
+
+public:
+  continuation() = default;
+  ~continuation() = default;
+  continuation(continuation const&) = delete;
+  continuation(continuation&&) = default;
+  continuation& operator=(continuation const&) = delete;
+  continuation& operator=(continuation&&) = default;
+
+  template <
+      typename T,
+      std::enable_if_t<std::is_convertible<T, erasure_t>::value>* = nullptr,
+      std::enable_if_t<!is_continuation<traits::unrefcv_t<T>>::value>* =
+          nullptr>
+  /* implicit */ continuation(T&& callable)
+      : erasure_(std::forward<T>(callable)) {
+  }
+
+  template <
+      typename T,
+      std::enable_if_t<std::is_assignable<erasure_t, T>::value>* = nullptr,
+      std::enable_if_t<!is_continuation<traits::unrefcv_t<T>>::value>* =
+          nullptr>
+  continuation& operator=(T&& callable) {
+    erasure_ = std::forward<T>(callable);
+    return *this;
+  }
+
+  void operator()(promise_base<callback<Args...>, //
+                               signature_arg_t<Args...>>
+                      promise) {
+    erasure_(std::move(promise));
+  }
+
+  bool operator()(is_ready_arg_t is_ready_arg) const {
+    return erasure_(is_ready_arg);
+  }
+
+  result<Args...> operator()(unpack_arg_t query_arg) {
+    return erasure_(query_arg);
+  }
+};
+#endif
+} // namespace erasure
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_ERASURE_HPP_INCLUDED

include/continuable/detail/other/promisify.hpp

@@ -0,0 +1,97 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.2.0
+
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_PROMISIFY_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_PROMISIFY_HPP_INCLUDED
+
+#include <type_traits>
+#include <continuable/continuable-base.hpp>
+#include <continuable/continuable-primitives.hpp>
+#include <continuable/detail/features.hpp>
+#include <continuable/detail/utility/traits.hpp>
+#include <continuable/detail/utility/util.hpp>
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#include <exception>
+#endif // CONTINUABLE_HAS_EXCEPTIONS
+
+namespace cti {
+namespace detail {
+namespace convert {
+/// A resolver for promisifying asio and js style callbacks.
+inline auto default_resolver() {
+  return [](auto&& promise, auto&& e, auto&&... args) {
+    static_assert(
+        std::is_convertible<std::decay_t<decltype(e)>, exception_t>::value,
+        "The given error type must be convertible to the error type used! "
+        "Specify a custom resolver in order to apply a conversion to the "
+        "used error type.");
+
+    if (e) {
+      promise.set_exception(std::forward<decltype(e)>(e));
+    } else {
+      promise.set_value(std::forward<decltype(args)>(args)...);
+    }
+  };
+}
+
+template <typename... Result>
+struct promisify_helper {
+  template <typename Resolver, typename Callable, typename... Args>
+  static auto from(Resolver&& resolver, Callable&& callable, Args&&... args) {
+    return make_continuable<Result...>(
+        [resolver = std::forward<Resolver>(resolver),
+         args = traits::make_flat_tuple(std::forward<Callable>(callable),
+                                        std::forward<Args>(args)...)](
+            auto&& promise) mutable {
+          traits::unpack(
+              [promise = std::forward<decltype(promise)>(promise),
+               &resolver](auto&&... args) mutable {
+                // Call the resolver from with the promise and result
+                auto callback =
+                    [resolver = std::move(resolver),
+                     promise = std::move(promise)](auto&&... args) mutable {
+                      resolver(std::move(promise),
+                               std::forward<decltype(args)>(args)...);
+                    };
+
+                // Invoke the callback taking function
+                util::invoke(std::forward<decltype(args)>(args)...,
+                             std::move(callback));
+              },
+              std::move(args));
+        });
+  }
+};
+} // namespace convert
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_PROMISIFY_HPP_INCLUDED

include/continuable/detail/other/testing.hpp

@@ -5,9 +5,9 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.2.0
 
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
+  Copyright(c) 2015 - 2022 Denis Blank <denis.blank at outlook dot com>
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files(the "Software"), to deal
@@ -21,7 +21,7 @@
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
@@ -33,13 +33,12 @@
 
 #include <type_traits>
 #include <utility>
-
 #include <gtest/gtest.h>
-
+#include <continuable/continuable-primitives.hpp>
+#include <continuable/detail/core/types.hpp>
 #include <continuable/detail/features.hpp>
-#include <continuable/detail/traits.hpp>
+#include <continuable/detail/utility/traits.hpp>
-#include <continuable/detail/types.hpp>
+#include <continuable/detail/utility/util.hpp>
-#include <continuable/detail/util.hpp>
 
 namespace cti {
 namespace detail {
@@ -55,7 +54,7 @@ void assert_async_completion(C&& continuable) {
         // Workaround for our known GCC bug.
         util::unused(std::forward<decltype(args)>(args)...);
       })
-      .fail([](cti::error_type /*error*/) {
+      .fail([](cti::exception_t /*error*/) {
         // ...
         FAIL();
       });
@@ -74,7 +73,28 @@ void assert_async_exception_completion(C&& continuable) {
         // ...
         FAIL();
       })
-      .fail([called](cti::error_type /*error*/) {
+      .fail([called](cti::exception_t error) {
+        ASSERT_TRUE(bool(error));
+        ASSERT_FALSE(*called);
+        *called = true;
+      });
+
+  ASSERT_TRUE(*called);
+}
+
+template <typename C>
+void assert_async_cancellation(C&& continuable) {
+  auto called = std::make_shared<bool>(false);
+  std::forward<C>(continuable)
+      .then([](auto&&... args) {
+        // Workaround for our known GCC bug.
+        util::unused(std::forward<decltype(args)>(args)...);
+
+        // ...
+        FAIL();
+      })
+      .fail([called](cti::exception_t error) {
+        ASSERT_FALSE(bool(error));
         ASSERT_FALSE(*called);
         *called = true;
       });
@@ -91,7 +111,7 @@ void assert_async_never_completed(C&& continuable) {
 
         FAIL();
       })
-      .fail([](cti::error_type /*error*/) {
+      .fail([](cti::exception_t) {
         // ...
         FAIL();
       });
@@ -101,11 +121,10 @@ template <typename C, typename V>
 void assert_async_validation(C&& continuable, V&& validator) {
   assert_async_completion(
       std::forward<C>(continuable)
-          .then([validator =
+          .then(
-                     std::forward<V>(validator)](auto&&... args) mutable {
+              [validator = std::forward<V>(validator)](auto&&... args) mutable {
-
+                validator(std::forward<decltype(args)>(args)...);
-            validator(std::forward<decltype(args)>(args)...);
+              }));
-          }));
 }
 
 /// Expects that the continuable is finished with the given arguments
@@ -115,18 +134,17 @@ void assert_async_binary_validation(V&& validator, C&& continuable,
 
   using size = std::integral_constant<std::size_t, sizeof...(expected)>;
 
-  assert_async_validation(std::forward<C>(continuable), [
+  assert_async_validation(
-    expected_pack = std::make_tuple(std::forward<Args>(expected)...),
+      std::forward<C>(continuable),
-    validator = std::forward<V>(validator)
+      [expected_pack = std::make_tuple(std::forward<Args>(expected)...),
-  ](auto&&... args) mutable {
+       validator = std::forward<V>(validator)](auto&&... args) mutable {
+        static_assert(size::value == sizeof...(args),
+                      "Async completion handler called with a different count "
+                      "of arguments!");
 
-    static_assert(size::value == sizeof...(args),
+        validator(std::make_tuple(std::forward<decltype(args)>(args)...),
-                  "Async completion handler called with a different count "
+                  expected_pack);
-                  "of arguments!");
+      });
-
-    validator(std::make_tuple(std::forward<decltype(args)>(args)...),
-              expected_pack);
-  });
 }
 
 /// Expects that the continuable is finished with the given arguments
@@ -139,20 +157,19 @@ void assert_async_binary_exception_validation(V&& validator, C&& continuable,
         // Workaround for our known GCC bug.
         util::unused(std::forward<decltype(args)>(args)...);
 
-        // ...
+        // The exception was not thrown!
         FAIL();
       })
-      .fail([
+      .fail([called, validator = std::forward<decltype(validator)>(validator),
-        called, validator = std::forward<decltype(validator)>(validator),
+             expected = std::forward<decltype(expected)>(expected)](
-        expected = std::forward<decltype(expected)>(expected)
+                exception_t error) {
-      ](types::error_type error) {
         ASSERT_FALSE(*called);
         *called = true;
 
 #if defined(CONTINUABLE_HAS_EXCEPTIONS)
         try {
           std::rethrow_exception(error);
-        } catch (std::decay_t<decltype(expected)>& exception) {
+        } catch (std::decay_t<decltype(expected)> const& exception) {
           validator(exception, expected);
         } catch (...) {
           FAIL();
@@ -183,15 +200,14 @@ template <typename... Expected>
 struct assert_async_types_validator {
   template <typename... Actual>
   void operator()(Actual...) {
-    static_assert(std::is_same<traits::identity<Actual...>,
+    static_assert(
-                               traits::identity<Expected...>>::value,
+        std::is_same<identity<Actual...>, identity<Expected...>>::value,
-                  "The called arguments don't match with the expected ones!");
+        "The called arguments don't match with the expected ones!");
   }
 };
 
 template <typename C, typename... Args>
-void assert_async_types(C&& continuable,
+void assert_async_types(C&& continuable, identity<Args...> /*expected*/) {
-                        traits::identity<Args...> /*expected*/) {
   assert_async_validation(std::forward<C>(continuable),
                           assert_async_types_validator<Args...>{});
 }

include/continuable/detail/promisify.hpp

@@ -1,95 +0,0 @@
-
-/*
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v3.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#ifndef CONTINUABLE_DETAIL_PROMISIFY_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_PROMISIFY_HPP_INCLUDED
-
-#include <type_traits>
-
-#if defined(CONTINUABLE_HAS_EXCEPTIONS)
-#include <exception>
-#endif // CONTINUABLE_HAS_EXCEPTIONS
-
-#include <continuable/continuable-base.hpp>
-#include <continuable/detail/traits.hpp>
-#include <continuable/detail/util.hpp>
-
-namespace cti {
-namespace detail {
-namespace convert {
-/// A helper class for promisifying asio style callback taking functions
-/// into a continuable.
-template <typename P>
-struct promisify_asio {
-  P promise;
-
-  template <typename E, typename... T>
-  void operator()(E&& error, T&&... result) {
-    if (error) {
-#if defined(CONTINUABLE_HAS_EXCEPTIONS)
-      promise.set_exception(std::make_exception_ptr(std::forward<E>(error)));
-#else
-      promise.set_exception(
-          std::error_condition(error.value(), error.category()));
-#endif // CONTINUABLE_HAS_EXCEPTIONS
-
-    } else {
-      promise.set_value(std::forward<T>(result)...);
-    }
-  }
-};
-
-template <typename... Result>
-struct promisify_helper {
-  template <template <class T> class Evaluator, typename Callable,
-            typename... Args>
-  static auto from(Callable&& callable, Args&&... args) {
-    return make_continuable<Result...>([args = std::make_tuple(
-                                            std::forward<Callable>(callable),
-                                            std::forward<Args>(args)...)](
-        auto&& promise) mutable {
-
-      traits::unpack(
-          std::move(args), [promise = std::forward<decltype(promise)>(promise)](
-                               auto&&... args) mutable {
-            Evaluator<std::decay_t<decltype(promise)>> evaluator{
-                std::move(promise)};
-
-            util::invoke(std::forward<decltype(args)>(args)...,
-                         std::move(evaluator));
-          });
-    });
-  }
-};
-} // namespace convert
-} // namespace detail
-} // namespace cti
-
-#endif // CONTINUABLE_DETAIL_PROMISIFY_HPP_INCLUDED

include/continuable/detail/traits.hpp

@@ -1,342 +0,0 @@
-
-/*
-
-                        /~` _  _ _|_. _     _ |_ | _
-                        \_,(_)| | | || ||_|(_||_)|(/_
-
-                    https://github.com/Naios/continuable
-                                   v3.0.0
-
-  Copyright(c) 2015 - 2018 Denis Blank <denis.blank at outlook dot com>
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy
-  of this software and associated documentation files(the "Software"), to deal
-  in the Software without restriction, including without limitation the rights
-  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
-  copies of the Software, and to permit persons to whom the Software is
-  furnished to do so, subject to the following conditions :
-
-  The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-**/
-
-#ifndef CONTINUABLE_DETAIL_TRAITS_HPP_INCLUDED
-#define CONTINUABLE_DETAIL_TRAITS_HPP_INCLUDED
-
-#include <cstdint>
-#include <initializer_list>
-#include <tuple>
-#include <type_traits>
-#include <utility>
-
-#include <continuable/detail/features.hpp>
-
-namespace cti {
-namespace detail {
-namespace traits {
-/// Evaluates to the element at position I.
-template <std::size_t I, typename... Args>
-using at_t = decltype(std::get<I>(std::declval<std::tuple<Args...>>()));
-
-/// A tagging type for wrapping other types
-template <typename... T>
-struct identity {};
-template <typename T>
-struct identity<T> : std::common_type<T> {};
-
-template <typename>
-struct is_identity : std::false_type {};
-template <typename... Args>
-struct is_identity<identity<Args...>> : std::true_type {};
-
-template <typename T>
-constexpr identity<std::decay_t<T>> identity_of(T const& /*type*/) noexcept {
-  return {};
-}
-template <typename... Args>
-constexpr identity<Args...> identity_of(identity<Args...> /*type*/) noexcept {
-  return {};
-}
-template <typename T>
-using identify = std::conditional_t<is_identity<std::decay_t<T>>::value, T,
-                                    identity<std::decay_t<T>>>;
-
-template <std::size_t I, typename... T>
-constexpr auto get(identity<T...>) noexcept {
-  return identify<at_t<I, T...>>{};
-}
-
-namespace detail {
-// Equivalent to C++17's std::void_t which targets a bug in GCC,
-// that prevents correct SFINAE behavior.
-// See http://stackoverflow.com/questions/35753920 for details.
-template <typename...>
-struct deduce_to_void : std::common_type<void> {};
-} // namespace detail
-
-/// C++17 like void_t type
-template <typename... T>
-using void_t = typename detail::deduce_to_void<T...>::type;
-
-namespace detail {
-template <typename Type, typename TrueCallback>
-constexpr void static_if_impl(std::true_type, Type&& type,
-                              TrueCallback&& trueCallback) {
-  std::forward<TrueCallback>(trueCallback)(std::forward<Type>(type));
-}
-
-template <typename Type, typename TrueCallback>
-constexpr void static_if_impl(std::false_type, Type&& /*type*/,
-                              TrueCallback&& /*trueCallback*/) {
-}
-
-template <typename Type, typename TrueCallback, typename FalseCallback>
-constexpr auto static_if_impl(std::true_type, Type&& type,
-                              TrueCallback&& trueCallback,
-                              FalseCallback&& /*falseCallback*/) {
-  return std::forward<TrueCallback>(trueCallback)(std::forward<Type>(type));
-}
-
-template <typename Type, typename TrueCallback, typename FalseCallback>
-constexpr auto static_if_impl(std::false_type, Type&& type,
-                              TrueCallback&& /*trueCallback*/,
-                              FalseCallback&& falseCallback) {
-  return std::forward<FalseCallback>(falseCallback)(std::forward<Type>(type));
-}
-
-/// Evaluates to the size of the given tuple like type,
-// / if the type has no static size it will be one.
-template <typename T, typename Enable = void>
-struct tuple_like_size : std::integral_constant<std::size_t, 1U> {};
-template <typename T>
-struct tuple_like_size<T, void_t<decltype(std::tuple_size<T>::value)>>
-    : std::tuple_size<T> {};
-} // namespace detail
-
-/// Returns the pack size of the given empty pack
-constexpr std::size_t pack_size_of(identity<>) noexcept {
-  return 0U;
-}
-/// Returns the pack size of the given type
-template <typename T>
-constexpr std::size_t pack_size_of(identity<T>) noexcept {
-  return detail::tuple_like_size<T>::value;
-}
-/// Returns the pack size of the given type
-template <typename First, typename Second, typename... Args>
-constexpr std::size_t pack_size_of(identity<First, Second, Args...>) noexcept {
-  return 2U + sizeof...(Args);
-}
-
-/// Returns an index sequence of the given type
-template <typename T>
-constexpr auto sequence_of(identity<T>) noexcept {
-  constexpr auto const size = pack_size_of(identity<T>{});
-  return std::make_index_sequence<size>();
-}
-
-/// Invokes the callback only if the given type matches the check
-template <typename Type, typename Check, typename TrueCallback>
-constexpr void static_if(Type&& type, Check&& check,
-                         TrueCallback&& trueCallback) {
-  detail::static_if_impl(std::forward<Check>(check)(type),
-                         std::forward<Type>(type),
-                         std::forward<TrueCallback>(trueCallback));
-}
-
-/// Invokes the callback only if the given type matches the check
-template <typename Type, typename Check, typename TrueCallback,
-          typename FalseCallback>
-constexpr auto static_if(Type&& type, Check&& check,
-                         TrueCallback&& trueCallback,
-                         FalseCallback&& falseCallback) {
-  return detail::static_if_impl(std::forward<Check>(check)(type),
-                                std::forward<Type>(type),
-                                std::forward<TrueCallback>(trueCallback),
-                                std::forward<FalseCallback>(falseCallback));
-}
-
-/// Calls the given unpacker with the content of the given sequence
-template <typename U, std::size_t... I>
-constexpr decltype(auto) unpack(std::integer_sequence<std::size_t, I...>,
-                                U&& unpacker) {
-  return std::forward<U>(unpacker)(std::integral_constant<std::size_t, I>{}...);
-}
-
-/// Calls the given unpacker with the content of the given sequenceable
-template <typename F, typename U, std::size_t... I>
-constexpr auto unpack(F&& first_sequenceable, U&& unpacker,
-                      std::integer_sequence<std::size_t, I...>)
-    -> decltype(std::forward<U>(unpacker)(
-        get<I>(std::forward<F>(first_sequenceable))...)) {
-  (void)first_sequenceable;
-  return std::forward<U>(unpacker)(
-      get<I>(std::forward<F>(first_sequenceable))...);
-}
-/// Calls the given unpacker with the content of the given sequenceable
-template <typename F, typename S, typename U, std::size_t... If,
-          std::size_t... Is>
-constexpr auto unpack(F&& first_sequenceable, S&& second_sequenceable,
-                      U&& unpacker, std::integer_sequence<std::size_t, If...>,
-                      std::integer_sequence<std::size_t, Is...>)
-    -> decltype(std::forward<U>(unpacker)(
-        get<If>(std::forward<F>(first_sequenceable))...,
-        get<Is>(std::forward<S>(second_sequenceable))...)) {
-  (void)first_sequenceable;
-  (void)second_sequenceable;
-  return std::forward<U>(unpacker)(
-      get<If>(std::forward<F>(first_sequenceable))...,
-      get<Is>(std::forward<S>(second_sequenceable))...);
-}
-/// Calls the given unpacker with the content of the given sequenceable
-template <typename F, typename U>
-constexpr auto unpack(F&& first_sequenceable, U&& unpacker)
-    -> decltype(unpack(std::forward<F>(first_sequenceable),
-                       std::forward<U>(unpacker),
-                       sequence_of(identify<decltype(first_sequenceable)>{}))) {
-  return unpack(std::forward<F>(first_sequenceable), std::forward<U>(unpacker),
-                sequence_of(identify<decltype(first_sequenceable)>{}));
-}
-/// Calls the given unpacker with the content of the given sequenceables
-template <typename F, typename S, typename U>
-constexpr auto unpack(F&& first_sequenceable, S&& second_sequenceable,
-                      U&& unpacker)
-    -> decltype(unpack(std::forward<F>(first_sequenceable),
-                       std::forward<S>(second_sequenceable),
-                       std::forward<U>(unpacker),
-                       sequence_of(identity_of(first_sequenceable)),
-                       sequence_of(identity_of(second_sequenceable)))) {
-  return unpack(std::forward<F>(first_sequenceable),
-                std::forward<S>(second_sequenceable), std::forward<U>(unpacker),
-                sequence_of(identity_of(first_sequenceable)),
-                sequence_of(identity_of(second_sequenceable)));
-}
-
-/// Adds the given type at the back of the left sequenceable
-template <typename Left, typename Element>
-constexpr auto push(Left&& left, Element&& element) {
-  return unpack(std::forward<Left>(left), [&](auto&&... args) {
-    return std::make_tuple(std::forward<decltype(args)>(args)...,
-                           std::forward<Element>(element));
-  });
-}
-
-/// Adds the element to the back of the identity
-template <typename... Args, typename Element>
-constexpr auto push(identity<Args...>, identity<Element>) noexcept {
-  return identity<Args..., Element>{};
-}
-
-/// Removes the first element from the identity
-template <typename First, typename... Rest>
-constexpr auto pop_first(identity<First, Rest...>) noexcept {
-  return identity<Rest...>{};
-}
-
-/// Returns the merged sequence
-template <typename Left>
-constexpr auto merge(Left&& left) {
-  return std::forward<Left>(left);
-}
-/// Merges the left sequenceable with the right ones
-template <typename Left, typename Right, typename... Rest>
-constexpr auto merge(Left&& left, Right&& right, Rest&&... rest) {
-  // Merge the left with the right sequenceable and
-  // merge the result with the rest.
-  return merge(unpack(std::forward<Left>(left), std::forward<Right>(right),
-                      [&](auto&&... args) {
-                        // Maybe use: template <template<typename...> class T,
-                        // typename... Args>
-                        return std::make_tuple(
-                            std::forward<decltype(args)>(args)...);
-                      }),
-               std::forward<Rest>(rest)...);
-}
-/// Merges the left identity with the right ones
-template <typename... LeftArgs, typename... RightArgs, typename... Rest>
-constexpr auto merge(identity<LeftArgs...> /*left*/,
-                     identity<RightArgs...> /*right*/, Rest&&... rest) {
-  return merge(identity<LeftArgs..., RightArgs...>{},
-               std::forward<Rest>(rest)...);
-}
-
-namespace detail {
-template <typename T, typename Args, typename = traits::void_t<>>
-struct is_invokable_impl : std::common_type<std::false_type> {};
-
-template <typename T, typename... Args>
-struct is_invokable_impl<
-    T, std::tuple<Args...>,
-    void_t<decltype(std::declval<T>()(std::declval<Args>()...))>>
-    : std::common_type<std::true_type> {};
-} // namespace detail
-
-/// Deduces to a std::true_type if the given type is callable with the arguments
-/// inside the given tuple.
-/// The main reason for implementing it with the detection idiom instead of
-/// hana like detection is that MSVC has issues with capturing raw template
-/// arguments inside lambda closures.
-///
-/// ```cpp
-/// traits::is_invokable<object, std::tuple<Args...>>
-/// ```
-template <typename T, typename Args>
-using is_invokable_from_tuple =
-    typename detail::is_invokable_impl<T, Args>::type;
-
-// Checks whether the given callable object is invocable with the given
-// arguments. This doesn't take member functions into account!
-template <typename T, typename... Args>
-using is_invocable = is_invokable_from_tuple<T, std::tuple<Args...>>;
-
-/// Deduces to a std::false_type
-template <typename T>
-using fail = std::integral_constant<bool, !std::is_same<T, T>::value>;
-
-#ifdef CONTINUABLE_HAS_CXX17_DISJUNCTION
-using std::disjunction;
-#else
-namespace detail {
-/// Declares a C++14 polyfill for C++17 std::disjunction.
-template <typename Args, typename = void_t<>>
-struct disjunction_impl : std::common_type<std::true_type> {};
-template <typename... Args>
-struct disjunction_impl<identity<Args...>,
-                        void_t<std::enable_if_t<!bool(Args::value)>...>>
-    : std::common_type<std::false_type> {};
-} // namespace detail
-
-template <typename... Args>
-using disjunction = typename detail::disjunction_impl<identity<Args...>>::type;
-#endif // CONTINUABLE_HAS_CXX17_DISJUNCTION
-
-#ifdef CONTINUABLE_HAS_CXX17_CONJUNCTION
-using std::conjunction;
-#else
-namespace detail {
-/// Declares a C++14 polyfill for C++17 std::conjunction.
-template <typename Args, typename = void_t<>>
-struct conjunction_impl : std::common_type<std::false_type> {};
-template <typename... Args>
-struct conjunction_impl<identity<Args...>,
-                        void_t<std::enable_if_t<bool(Args::value)>...>>
-    : std::common_type<std::true_type> {};
-} // namespace detail
-
-template <typename... Args>
-using conjunction = typename detail::conjunction_impl<identity<Args...>>::type;
-#endif // CONTINUABLE_HAS_CXX17_CONJUNCTION
-
-} // namespace traits
-} // namespace detail
-} // namespace cti
-
-#endif // CONTINUABLE_DETAIL_TRAITS_HPP_INCLUDED