From 8d851d6d42ff236228d56336883b8b2384fa357d Mon Sep 17 00:00:00 2001
From: Denis Blank <denis.blank@outlook.com>
Date: Fri, 3 Mar 2017 17:10:29 +0100
Subject: [PATCH] Rework the alias trait

---
 include/continuable/continuable-base.hpp    | 29 ++++++++--
 include/continuable/continuable-testing.hpp |  2 +-
 include/continuable/continuable.hpp         | 63 +++++++++++++++++----
 test/playground/test-playground.cpp         | 25 --------
 test/unit-test/test-continuable-erasure.cpp | 11 ++++
 5 files changed, 86 insertions(+), 44 deletions(-)

diff --git a/include/continuable/continuable-base.hpp b/include/continuable/continuable-base.hpp
index c5def58..d3d289d 100644
--- a/include/continuable/continuable-base.hpp
+++ b/include/continuable/continuable-base.hpp
@@ -5,7 +5,7 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-
+                                   v0.8.0
 
   Copyright(c) 2015 - 2017 Denis Blank <denis.blank at outlook dot com>
 
@@ -1997,14 +1997,31 @@ auto seq_of(Continuables&&... continuables) {
                             std::forward<Continuables>(continuables)...);
 }
 
+/// 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 <typename> class CallbackWrapper,
           template <typename> class ContinuationWrapper, typename... Args>
-using continuable_erasure_of_t =
-    CallbackWrapper<void(ContinuationWrapper<void(Args...)>)>;
+struct continuable_trait {
+  /// The callback type which is passed to continuations
+  using callback = CallbackWrapper<void(Args...)>;
 
-template <typename Erasure, typename... Args>
-using continuable_of_t =
-    continuable_base<Erasure, detail::signature_hint_tag<Args...>>;
+  /// The continuation type which is used to erase the internal data.
+  using continuation =
+      ContinuationWrapper<void(CallbackWrapper<void(Args...)>)>;
+
+  /// The continuable type for the given parameters.
+  using continuable =
+      continuable_base<continuation, detail::signature_hint_tag<Args...>>;
+};
 
 /// \cond false
 } // end inline namespace abi_...
diff --git a/include/continuable/continuable-testing.hpp b/include/continuable/continuable-testing.hpp
index 3a3b518..e425be2 100644
--- a/include/continuable/continuable-testing.hpp
+++ b/include/continuable/continuable-testing.hpp
@@ -5,7 +5,7 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-
+                                   v0.8.0
 
   Copyright(c) 2015 - 2017 Denis Blank <denis.blank at outlook dot com>
 
diff --git a/include/continuable/continuable.hpp b/include/continuable/continuable.hpp
index 075579d..940c637 100644
--- a/include/continuable/continuable.hpp
+++ b/include/continuable/continuable.hpp
@@ -5,7 +5,7 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-
+                                   v0.8.0
 
   Copyright(c) 2015 - 2017 Denis Blank <denis.blank at outlook dot com>
 
@@ -31,30 +31,69 @@
 #ifndef CONTINUABLE_HPP_INCLUDED__
 #define CONTINUABLE_HPP_INCLUDED__
 
-#include <type_traits>
-
 #include "continuable/continuable-base.hpp"
 #include "function2/function2.hpp"
 
 namespace cti {
+// clang-format off
+/// \cond false
+inline namespace abi_v1 {
+/// \endcond
+namespace detail {
+template<typename... Args>
+using trait_of = continuable_trait<
+  fu2::function,
+  fu2::function,
+  Args...
+>;
+
+template<typename... Args>
+using unique_trait_of = continuable_trait<
+  fu2::unique_function,
+  fu2::unique_function,
+  Args...
+>;
+} // end namespace detail
+
 /// Defines a copyable continuation type which uses the
 /// function2 backend for type erasure.
 ///
-/// Usable like: continuable<int, float>
+/// Usable like: `cti::continuable<int, float>`
 template <typename... Args>
-using continuable = continuable_of_t<
-    continuable_erasure_of_t<fu2::function, fu2::unique_function, Args...>,
-    Args...>;
+using continuable = typename detail::trait_of<
+  Args...
+>::continuable;
+
+/// Defines a copyable callback type which uses the
+/// function2 backend for the continuable type erasure.
+///
+/// Usable like: `callback<int, float>`
+template <typename... Args>
+using callback = typename detail::trait_of<
+  Args...
+>::callback;
 
 /// Defines a non-copyable continuation type which uses the
 /// function2 backend for type erasure.
 ///
-/// Usable like: unique_continuable<int, float>
+/// Usable like: `unique_continuable<int, float>`
 template <typename... Args>
-using unique_continuable =
-    continuable_of_t<continuable_erasure_of_t<fu2::unique_function,
-                                              fu2::unique_function, Args...>,
-                     Args...>;
+using unique_continuable = typename detail::unique_trait_of<
+  Args...
+>::continuable;
+
+/// Defines a non-copyable callback type which uses the
+/// function2 backend for the continuable type erasure.
+///
+/// Usable like: `unique_callback<int, float>`
+template <typename... Args>
+using unique_callback = typename detail::unique_trait_of<
+  Args...
+>::callback;
+/// \cond false
+} // end inline namespace abi_...
+/// \endcond
+// clang-format on
 } // end namespace cti
 
 #endif // CONTINUABLE_HPP_INCLUDED__
diff --git a/test/playground/test-playground.cpp b/test/playground/test-playground.cpp
index 0e355f2..24f15ee 100644
--- a/test/playground/test-playground.cpp
+++ b/test/playground/test-playground.cpp
@@ -22,31 +22,6 @@
 
 #include "continuable/continuable.hpp"
 
-using namespace cti::detail;
-using namespace cti::detail::util;
-
-/// Predicate to check whether an object is callable with the given arguments
-template <typename... Args> auto is_invokable_with(identity<Args...>) {
-  return [](auto&& callable) {
-    (void)callable;
-    return is_invokable_t<decltype(callable), identity<Args...>>{};
-  };
-}
-
-template <typename... Right>
-auto reverse(identity<>, identity<Right...> right = identity<>{}) {
-  return right;
-}
-template <typename First, typename... Left, typename... Right>
-auto reverse(identity<First, Left...>, identity<Right...> = identity<>{}) {
-  return reverse(identity<Left...>{}, identity<First, Right...>{});
-}
-
 int main(int, char**) {
-
-  auto cb = [](int, int) { return 0; };
-
-  partial_invoke(cb, 0, 0, 0, 0, 0, 0, 0);
-
   return 0;
 }
diff --git a/test/unit-test/test-continuable-erasure.cpp b/test/unit-test/test-continuable-erasure.cpp
index f61d708..52ad436 100644
--- a/test/unit-test/test-continuable-erasure.cpp
+++ b/test/unit-test/test-continuable-erasure.cpp
@@ -38,3 +38,14 @@ TYPED_TEST(single_dimension_tests, is_eraseable) {
     EXPECT_ASYNC_RESULT(std::move(erasure), 0xDF);
   }
 }
+
+TYPED_TEST(single_dimension_tests, is_callable) {
+
+  cti::unique_continuable<int, int> erased =
+      [](cti::unique_callback<int, int>&& callback) {
+
+        std::move(callback)(0xDF, 0xDD);
+      };
+
+  EXPECT_ASYNC_RESULT(std::move(erased), 0xDF, 0xDD);
+}