🎨 Committing clang-format changes

* Fix #458: Support std::string_view interop with ChaiScript strings

Register std::string_view as the "string_view" user type with a built-in
implicit conversion from std::string, so a ChaiScript string can be passed
directly to a C++ function taking std::string_view. Adds the reverse
explicit conversion via string(sv) / to_string(sv), plus basic queries
(size, length, empty, data) and comparison operators on string_view.
String-style methods that take size_t (substr, find, ...) are intentionally
not duplicated on string_view: with the implicit conversion in place they
would create dispatch ambiguity for calls like string.substr(int, int).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Address review: expand string_view binding with substr/find/[]

Adds substr, find/rfind/find_first_of/find_last_of/find_first_not_of/
find_last_not_of, starts_with/ends_with, and operator[] to string_view_type,
mirroring string_type's search/substring surface so script authors can
traverse a buffer through string_view without allocating.

Sharing method names with string_type creates an ambiguity in
dispatch_with_conversions when the script call needs arithmetic conversion
(e.g. myString.substr(int, int)): both string::substr and string_view::substr
match-except-for-arithmetic, and the existing const/non-const tiebreaker
doesn't apply. Extend dispatch_with_conversions to prefer the candidate
whose first/receiver parameter type exactly matches the actual receiver,
mirroring the deprioritization already in dispatch(). With this in place,
myString.substr(1, 2) still resolves to string::substr while
mySV.substr(1, 2) resolves to string_view::substr (returning a string_view).

Updates the doc comment on string_view_type and adds a compiled test that
locks in both dispatch directions plus the new search/substring methods.

Requested by @lefticus in PR #697 review.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: leftibot <leftibot@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.clang-format

@@ -1,10 +1,14 @@
-# clang-format: 11
+# clang-format: 19
 AccessModifierOffset:                 -2
 AlignAfterOpenBracket:                Align
 AlignConsecutiveBitFields:            false
-AllowShortBlocksOnASingleLine:        false
+AllowShortBlocksOnASingleLine:        Always
+AllowShortCaseLabelsOnASingleLine:    true
+AllowShortEnumsOnASingleLine:         true
 AllowShortFunctionsOnASingleLine:     Inline
+AllowShortIfStatementsOnASingleLine:  AllIfsAndElse
 AllowShortLambdasOnASingleLine:       All
+AllowShortLoopsOnASingleLine:         true
 AlwaysBreakTemplateDeclarations:      true
 BasedOnStyle:                         WebKit
 BinPackArguments:                     true
@@ -13,12 +17,14 @@ BreakBeforeBraces:                    Attach
 ColumnLimit:                          0
 Cpp11BracedListStyle:                 true
 FixNamespaceComments:                 true
+IfMacros:                             ['SECTION']
 IncludeBlocks:                        Preserve
 IndentCaseLabels:                     true
 IndentPPDirectives:                   None
 IndentWidth:                          2
 KeepEmptyLinesAtTheStartOfBlocks:     false
 NamespaceIndentation:                 All
+PackConstructorInitializers:          CurrentLine
 PenaltyBreakBeforeFirstCallParameter: 200
 PenaltyBreakComment:                  5
 PenaltyBreakFirstLessLess:            50
@@ -27,6 +33,10 @@ PointerAlignment:                     Right
 SortIncludes:                         true
 SpaceAfterTemplateKeyword:            false
 SpaceBeforeCpp11BracedList:           false
+SpaceBeforeParens:                    Custom
+SpaceBeforeParensOptions:
+  AfterControlStatements:             true
+  AfterIfMacros:                      false
 SpaceInEmptyBlock:                    false
 Standard:                             Latest
 TabWidth:                             2

.github/workflows/auto-clang-format.yml

@@ -0,0 +1,27 @@
+name: auto-clang-format
+on:
+  push:
+    branches:
+      - develop
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v6
+    - uses: DoozyX/clang-format-lint-action@v0.20
+      with:
+        source: '.'
+        exclude: './third_party ./external ./unittests/catch.hpp'
+        extensions: 'h,cpp,hpp'
+        clangFormatVersion: 19
+        inplace: True
+    - uses: EndBug/add-and-commit@v9
+      with:
+        author_name: Clang Robot
+        author_email: robot@example.com
+        message: ':art: Committing clang-format changes'
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/ci.yml

@@ -9,39 +9,47 @@ on:
 
 jobs:
   linux:
-    name: Linux GCC ${{ matrix.build_type }}
+    name: Linux GCC ${{ matrix.build_type }} threads=${{ matrix.multithread }}
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
         build_type: [Debug, Release]
+        multithread: [ON, OFF]
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install Ninja
+        run: sudo apt-get install -y ninja-build
+
       - name: Configure
-        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
+        run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DMULTITHREAD_SUPPORT_ENABLED=${{ matrix.multithread }}
 
       - name: Build
-        run: cmake --build build -j
+        run: cmake --build build
 
       - name: Test
         run: ctest --test-dir build --output-on-failure
 
   macos:
-    name: macOS AppleClang ${{ matrix.build_type }}
+    name: macOS AppleClang ${{ matrix.build_type }} threads=${{ matrix.multithread }}
     runs-on: macos-latest
     strategy:
       fail-fast: false
       matrix:
         build_type: [Debug, Release]
+        multithread: [ON, OFF]
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install Ninja
+        run: brew install ninja
+
       - name: Configure
-        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
+        run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DMULTITHREAD_SUPPORT_ENABLED=${{ matrix.multithread }}
 
       - name: Build
-        run: cmake --build build -j
+        run: cmake --build build
 
       - name: Test
         run: ctest --test-dir build --output-on-failure
@@ -56,11 +64,14 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install Ninja
+        run: sudo apt-get install -y ninja-build
+
       - name: Configure
-        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_ADDRESS_SANITIZER=ON -DENABLE_UNDEFINED_SANITIZER=ON
+        run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_ADDRESS_SANITIZER=ON -DENABLE_UNDEFINED_SANITIZER=ON
 
       - name: Build
-        run: cmake --build build -j
+        run: cmake --build build
 
       - name: Test
         run: ctest --test-dir build --output-on-failure
@@ -75,27 +86,31 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install Ninja
+        run: brew install ninja
+
       - name: Configure
-        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_ADDRESS_SANITIZER=ON -DENABLE_UNDEFINED_SANITIZER=ON
+        run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_ADDRESS_SANITIZER=ON -DENABLE_UNDEFINED_SANITIZER=ON
 
       - name: Build
-        run: cmake --build build -j
+        run: cmake --build build
 
       - name: Test
         run: ctest --test-dir build --output-on-failure
 
   windows:
-    name: Windows MSVC ${{ matrix.build_type }}
+    name: Windows MSVC ${{ matrix.build_type }} threads=${{ matrix.multithread }}
     runs-on: windows-latest
     strategy:
       fail-fast: false
       matrix:
         build_type: [Debug, Release]
+        multithread: [ON, OFF]
     steps:
       - uses: actions/checkout@v4
 
       - name: Configure
-        run: cmake -B build
+        run: cmake -B build -DMULTITHREAD_SUPPORT_ENABLED=${{ matrix.multithread }}
 
       - name: Build
         run: cmake --build build --config ${{ matrix.build_type }} -j
@@ -113,11 +128,14 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install Ninja
+        run: sudo apt-get install -y ninja-build
+
       - name: Configure
-        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_THREAD_SANITIZER=ON
+        run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_THREAD_SANITIZER=ON -DMULTITHREAD_SUPPORT_ENABLED=ON
 
       - name: Build
-        run: cmake --build build -j
+        run: cmake --build build
 
       - name: Test
         run: ctest --test-dir build --output-on-failure
@@ -132,11 +150,14 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install Ninja
+        run: brew install ninja
+
       - name: Configure
-        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_THREAD_SANITIZER=ON
+        run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_THREAD_SANITIZER=ON -DMULTITHREAD_SUPPORT_ENABLED=ON
 
       - name: Build
-        run: cmake --build build -j
+        run: cmake --build build
 
       - name: Test
         run: ctest --test-dir build --output-on-failure

CMakeLists.txt

@@ -155,7 +155,7 @@ else()
 endif()
 
 if(MSVC)
-  add_definitions(/W4 /w14545 /w34242 /w34254 /w34287 /w44263 /w44265 /w44296 /w44311 /w44826 /we4289 /w14546 /w14547 /w14549 /w14555 /w14619 /w14905 /w14906 /w14928)
+  add_definitions(/WX /W4 /w14545 /w34242 /w34254 /w34287 /w44263 /w44265 /w44296 /w44311 /w44826 /we4289 /w14546 /w14547 /w14549 /w14555 /w14619 /w14905 /w14906 /w14928)
 
   if(MSVC_VERSION STREQUAL "1800")
     # VS2013 doesn't have magic statics
@@ -175,10 +175,10 @@ if(MSVC)
   # how to workaround or fix the error. So I'm disabling it globally.
   add_definitions(/wd4503)
 else()
-  add_definitions(-Wall -Wextra -Wconversion -Wshadow -Wnon-virtual-dtor -Wold-style-cast -Wcast-align -Wcast-qual -Wunused -Woverloaded-virtual -Wno-noexcept-type -Wpedantic -Werror=return-type)
+  add_definitions(-Werror -Wall -Wextra -Wconversion -Wshadow -Wnon-virtual-dtor -Wold-style-cast -Wcast-align -Wcast-qual -Wunused -Woverloaded-virtual -Wno-noexcept-type -Wpedantic -Werror=return-type)
 
   if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
-    add_definitions(-Weverything -Wno-c++98-compat-pedantic  -Wno-c++98-compat -Wno-documentation -Wno-switch-enum -Wno-weak-vtables -Wno-missing-prototypes -Wno-padded -Wno-missing-noreturn -Wno-exit-time-destructors -Wno-documentation-unknown-command -Wno-unused-template -Wno-undef -Wno-double-promotion)
+    add_definitions(-Weverything -Wno-c++98-compat-pedantic  -Wno-c++98-compat -Wno-documentation -Wno-switch-enum -Wno-weak-vtables -Wno-missing-prototypes -Wno-padded -Wno-missing-noreturn -Wno-exit-time-destructors -Wno-documentation-unknown-command -Wno-unused-template -Wno-undef -Wno-double-promotion -Wno-switch-default -Wno-nrvo -Wno-shadow-uncaptured-local -Wno-unsafe-buffer-usage-in-libc-call -Wno-c++20-extensions -Wno-unknown-warning-option -Wno-poison-system-directories -Wno-c++20-compat -Wno-c++17-compat)
   else()
     add_definitions(-Wnoexcept)
   endif()
@@ -292,6 +292,16 @@ endif()
 file(GLOB UNIT_TESTS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR}/unittests/ ${CMAKE_CURRENT_SOURCE_DIR}/unittests/*.chai ${CMAKE_CURRENT_SOURCE_DIR}/unittests/3.x/*.chai)
 list(SORT UNIT_TESTS)
 
+if(NOT MULTITHREAD_SUPPORT_ENABLED)
+  list(REMOVE_ITEM UNIT_TESTS
+    async_engine_lifetime.chai
+    async_return_value.chai
+    future.chai
+    list_push_front.chai
+    move_async.chai
+  )
+endif()
+
 file(GLOB PERFORMANCE_TESTS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR}/performance_tests/ ${CMAKE_CURRENT_SOURCE_DIR}/performance_tests/*.chai)
 list(SORT PERFORMANCE_TESTS)
 
@@ -380,8 +390,16 @@ if(BUILD_TESTING)
   )
 
   if(NOT UNIT_TEST_LIGHT)
+    add_library(catch2 STATIC unittests/catch_amalgamated.cpp)
+    if(NOT MSVC)
+      target_compile_options(catch2 PRIVATE -Wno-conversion -Wno-noexcept -Wno-maybe-uninitialized)
+    endif()
+    if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
+      target_compile_options(catch2 PUBLIC -Wno-unknown-warning-option -Wno-covered-switch-default -Wno-disabled-macro-expansion -Wno-unsafe-buffer-usage -Wno-unused-macros)
+    endif()
+
     add_executable(compiled_tests unittests/compiled_tests.cpp)
-    target_link_libraries(compiled_tests ${LIBS} ${CHAISCRIPT_LIBS})
+    target_link_libraries(compiled_tests catch2 ${LIBS} ${CHAISCRIPT_LIBS})
     catch_discover_tests(compiled_tests TEST_PREFIX "compiled.")
 
     add_executable(static_chaiscript_test unittests/static_chaiscript.cpp)
@@ -393,7 +411,7 @@ if(BUILD_TESTING)
     add_test(NAME Boxed_Cast_Test COMMAND boxed_cast_test)
 
     add_executable(type_info_test unittests/type_info_test.cpp)
-    target_link_libraries(type_info_test ${LIBS})
+    target_link_libraries(type_info_test catch2 ${LIBS})
     add_test(NAME Type_Info_Test COMMAND type_info_test)
 
     add_executable(c_linkage_test unittests/c_linkage_test.cpp)
@@ -413,6 +431,9 @@ if(BUILD_TESTING)
         "CHAI_USE_PATH=${CMAKE_CURRENT_SOURCE_DIR}/unittests/"
         "CHAI_MODULE_PATH=${CMAKE_CURRENT_BINARY_DIR}/"
       )
+      add_executable(async_engine_lifetime_test unittests/async_engine_lifetime_test.cpp)
+      target_link_libraries(async_engine_lifetime_test ${LIBS})
+      add_test(NAME Async_Engine_Lifetime_Test COMMAND async_engine_lifetime_test)
     endif()
 
     add_executable(multifile_test
@@ -427,6 +448,18 @@ if(BUILD_TESTING)
     target_link_libraries(emscripten_eval_test ${LIBS})
     add_test(NAME Emscripten_Eval_Test COMMAND emscripten_eval_test)
 
+    add_executable(emscripten_exception_test unittests/emscripten_exception_test.cpp)
+    target_link_libraries(emscripten_exception_test ${LIBS})
+    add_test(NAME Emscripten_Exception_Test COMMAND emscripten_exception_test)
+
+    add_executable(emscripten_state_test unittests/emscripten_state_test.cpp)
+    target_link_libraries(emscripten_state_test ${LIBS})
+    add_test(NAME Emscripten_State_Test COMMAND emscripten_state_test)
+
+    add_executable(threading_config_test unittests/threading_config_test.cpp)
+    target_link_libraries(threading_config_test ${LIBS})
+    add_test(NAME Threading_Config_Test COMMAND threading_config_test)
+
     install(TARGETS test_module RUNTIME DESTINATION bin LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}/chaiscript")
   endif()
 endif()

cheatsheet.md

@@ -16,6 +16,67 @@ chaiscript::ChaiScript chai; // initializes ChaiScript, adding the standard Chai
 
 Note that ChaiScript cannot be used as a global / static object unless it is being compiled with `CHAISCRIPT_NO_THREADS`.
 
+## Engine Options (`Options`)
+
+Engine-level options control which scripting capabilities are exposed. These are passed as a `std::vector<Options>` to the `ChaiScript` or `ChaiScript_Basic` constructor.
+
+| Option | Effect |
+|--------|--------|
+| `Options::Load_Modules` | Enables `load_module()` in scripts (default) |
+| `Options::No_Load_Modules` | Disables `load_module()` |
+| `Options::External_Scripts` | Enables `use()` and `eval_file()` in scripts (default) |
+| `Options::No_External_Scripts` | Disables `use()` and `eval_file()` |
+
+```cpp
+// Sandboxed engine: no dynamic module loading, no external script evaluation
+chaiscript::ChaiScript chai({}, {},
+    {chaiscript::Options::No_Load_Modules, chaiscript::Options::No_External_Scripts});
+```
+
+## Library Options (`Library_Options`)
+
+Library-level options control which parts of the standard library are registered. These are passed as a `std::vector<Library_Options>`.
+
+| Option | Effect |
+|--------|--------|
+| `Library_Options::No_Stdlib` | Disables the entire standard library (types, I/O, prelude, JSON — everything) |
+| `Library_Options::No_IO` | Disables `print_string` and `println_string` (and the prelude's `print`/`puts` wrappers) |
+| `Library_Options::No_Prelude` | Disables the ChaiScript prelude (`print`, `puts`, `filter`, `map`, `foldl`, `join`, etc.) |
+| `Library_Options::No_JSON` | Disables `from_json` and `to_json` |
+
+With the `ChaiScript` convenience class, pass library options as the fourth constructor parameter:
+
+```cpp
+// No I/O functions
+chaiscript::ChaiScript chai({}, {}, chaiscript::default_options(),
+    {chaiscript::Library_Options::No_IO});
+
+// No JSON support
+chaiscript::ChaiScript chai({}, {}, chaiscript::default_options(),
+    {chaiscript::Library_Options::No_JSON});
+
+// Completely bare engine — no stdlib at all
+chaiscript::ChaiScript chai({}, {}, chaiscript::default_options(),
+    {chaiscript::Library_Options::No_Stdlib});
+
+// Combine both: no external scripts and no I/O
+chaiscript::ChaiScript chai({}, {},
+    {chaiscript::Options::No_Load_Modules, chaiscript::Options::No_External_Scripts},
+    {chaiscript::Library_Options::No_IO});
+```
+
+With `ChaiScript_Basic`, pass library options directly to `Std_Lib::library()`:
+
+```cpp
+chaiscript::ChaiScript_Basic chai(
+    chaiscript::Std_Lib::library({chaiscript::Library_Options::No_IO}),
+    create_chaiscript_parser(),
+    {}, {},
+    {chaiscript::Options::No_Load_Modules, chaiscript::Options::No_External_Scripts});
+```
+
+Note: `No_Prelude` disables the prelude script which defines convenience functions like `print` (which wraps `print_string`). If you disable the prelude but not I/O, `print_string` and `println_string` are still available.
+
 # Adding Things To The Engine
 
 ## Adding a Function / Method / Member
@@ -604,6 +665,124 @@ copy.width = 99
 print(original.width)  // still 10
 ```
 
+## Enums
+
+ChaiScript supports strongly-typed enums using `enum class` (or equivalently `enum struct`),
+matching C++ scoped-enum semantics. Values are accessed via `::` syntax and are type-safe —
+a plain integer cannot be passed where an enum type is expected.
+
+### Basic Definition
+
+```
+enum class Color { Red, Green, Blue }
+```
+
+Values are auto-numbered starting from 0. Access them with `Color::Red`, `Color::Green`, etc.
+
+### Explicit Values
+
+```
+enum class Priority { Low = 10, Medium = 20, High = 30 }
+```
+
+Auto-numbering continues from the last explicit value:
+
+```
+enum class Status { Pending, Active = 5, Done }
+// Pending = 0, Active = 5, Done = 6
+```
+
+### Specifying an Underlying Type
+
+By default the underlying type is `int`. Use `: type` to choose a different numeric type:
+
+```
+enum class Flags : char { Read = 1, Write = 2, Execute = 4 }
+```
+
+The underlying type must be a numeric type registered in ChaiScript. `string` and other
+non-numeric types cannot be used. The available underlying types are:
+
+| Type | Description |
+|------|-------------|
+| `int` | (default) signed integer |
+| `unsigned_int` | unsigned integer |
+| `long` | signed long |
+| `unsigned_long` | unsigned long |
+| `long_long` | signed long long |
+| `unsigned_long_long` | unsigned long long |
+| `char` | character (8-bit) |
+| `wchar_t` | wide character |
+| `char16_t` | 16-bit character |
+| `char32_t` | 32-bit character |
+| `float` | single-precision float |
+| `double` | double-precision float |
+| `long_double` | extended-precision float |
+| `size_t` | unsigned size type |
+| `int8_t` | signed 8-bit |
+| `int16_t` | signed 16-bit |
+| `int32_t` | signed 32-bit |
+| `int64_t` | signed 64-bit |
+| `uint8_t` | unsigned 8-bit |
+| `uint16_t` | unsigned 16-bit |
+| `uint32_t` | unsigned 32-bit |
+
+### `enum struct` Syntax
+
+`enum struct` is accepted as a synonym for `enum class`, just like in C++:
+
+```
+enum struct Direction { North, East, South, West }
+```
+
+### Constructing from a Value
+
+Each enum type has a constructor that accepts the underlying type. It validates that the
+value matches one of the defined enumerators:
+
+```
+auto c = Color::Color(1)       // creates Color::Green
+Color::Color(52)               // throws: invalid value
+```
+
+### `to_underlying`
+
+Convert an enum value back to its underlying numeric type:
+
+```
+Color::Red.to_underlying()     // 0
+Priority::High.to_underlying() // 30
+```
+
+### Comparison
+
+`==` and `!=` are defined for values of the same enum type:
+
+```
+assert_true(Color::Red == Color::Red)
+assert_true(Color::Red != Color::Green)
+```
+
+### Type-Safe Dispatch
+
+Functions declared with an enum parameter type reject plain integers:
+
+```
+def handle(Color c) { /* ... */ }
+handle(Color::Red)    // ok
+handle(42)            // throws: dispatch error
+```
+
+### Using with `switch`
+
+```
+switch(Color::Green) {
+  case (Color::Red) { print("red"); break }
+  case (Color::Green) { print("green"); break }
+  case (Color::Blue) { print("blue"); break }
+}
+```
+
 ## Dynamic Objects
 
 All ChaiScript defined types and generic Dynamic_Object support dynamic parameters
@@ -650,6 +829,94 @@ class My_Class {
 };
 ```
 
+## Strong Typedefs
+
+Strong typedefs create distinct types that are not interchangeable with their underlying type
+or with other typedefs of the same underlying type. They use `Dynamic_Object` internally and
+automatically expose operators that the underlying type supports.
+
+### Basic Usage
+
+```
+using Meters = int
+using Seconds = int
+
+var d = Meters(100)
+var t = Seconds(10)
+
+// d and t are distinct types — you cannot accidentally mix them
+// Meters + Seconds would require an explicit conversion
+```
+
+### Arithmetic and Comparison
+
+Operators from the underlying type are forwarded and remain strongly typed:
+
+```
+using Meters = int
+
+var a = Meters(10)
+var b = Meters(20)
+
+var c = a + b        // Meters(30) — result is still Meters
+var bigger = b > a   // true — comparisons return bool
+
+// Compound assignment operators work too
+a += b               // a is now Meters(30)
+```
+
+### String-Based Strong Typedefs
+
+Strong typedefs work with any type, not just numeric types:
+
+```
+using Name = string
+
+var n = Name("Alice")
+var greeting = Name("Hello, ") + Name("world")  // Name — string concatenation is forwarded
+```
+
+### Accessing the Underlying Value
+
+Use `to_underlying` to extract the wrapped value:
+
+```
+using Meters = int
+
+var d = Meters(42)
+var raw = to_underlying(d)  // 42, plain int
+```
+
+### Extending Strong Typedefs
+
+You can add custom operations to strong typedefs just like any other ChaiScript type:
+
+```
+using Meters = int
+using Seconds = int
+using MetersPerSecond = int
+
+def speed(Meters d, Seconds t) {
+  MetersPerSecond(to_underlying(d) / to_underlying(t))
+}
+
+var s = speed(Meters(100), Seconds(10))  // MetersPerSecond(10)
+```
+
+You can also overload operators between different strong typedefs:
+
+```
+using Meters = int
+using Feet = int
+
+def to_feet(Meters m) {
+  Feet((to_underlying(m) * 328) / 100)
+}
+
+var m = Meters(10)
+var f = to_feet(m)  // Feet(32)
+```
+
 ## method_missing
 
 A function of the signature `method_missing(object, name, param1, param2, param3)` will be called if an appropriate
@@ -815,5 +1082,88 @@ m.is_type("MyClass")   // true (checks the ChaiScript class name)
  * `from_json` converts a JSON string into its strongly typed (map, vector, int, double, string) representations
  * `to_json` converts a ChaiScript object (either a `Object` or one of map, vector, int, double, string) tree into its JSON string representation
  
+## IO Redirection
+
+By default, ChaiScript's `print()` and `puts()` functions write to stdout. You can redirect
+output on a per-instance basis by setting a single print handler. Both `println_string`
+(used by `print()`) and `print_string` (used by `puts()`) dispatch through the same handler —
+`println_string` simply appends a newline before calling it.
+
+```cpp
+chaiscript::ChaiScript chai;
+
+// Redirect all output (print_string and println_string both use this handler)
+chai.set_print_handler([](const std::string &s) {
+  my_log_window.append(s);
+});
+```
+
+This is useful for embedding ChaiScript in GUI applications, logging frameworks, or any
+context where stdout is not the desired output destination.
+
+```cpp
+// Example: capture all output to a string
+std::string captured;
+chai.set_print_handler([&captured](const std::string &s) {
+  captured += s;
+});
+
+chai.eval("print(42)");    // captured == "42\n"
+chai.eval("puts(\"hi\")"); // captured == "42\nhi"
+```
+
+The print handler can also be set from within ChaiScript itself via `set_print_handler`:
+
+```chaiscript
+// Redirect output from within a script
+set_print_handler(fun(s) { my_custom_log(s) })
+```
+
+## Custom File Loading
+
+By default, ChaiScript reads files from the filesystem when `eval_file()` or `use()` is called.
+You can override this behavior on a per-instance basis by setting a custom file reader callback.
+This follows the same pattern as `set_print_handler` and enables use cases such as encrypted
+script files, in-memory virtual filesystems, or platform-specific file access (e.g., Android assets).
+
+```cpp
+chaiscript::ChaiScript chai;
+
+// Provide scripts from an in-memory map instead of the filesystem
+std::map<std::string, std::string> virtual_fs = {
+  {"init.chai", "var x = 42"},
+  {"utils.chai", "def add(a, b) { a + b }"}
+};
+
+chai.set_file_reader([&virtual_fs](const std::string &filename) -> std::string {
+  const auto it = virtual_fs.find(filename);
+  if (it != virtual_fs.end()) {
+    return it->second;
+  }
+  throw chaiscript::exception::file_not_found_error(filename);
+});
+
+chai.eval_file("init.chai"); // evaluates "var x = 42"
+chai.use("utils.chai");      // evaluates "def add(a, b) { a + b }"
+```
+
+The file reader can also be set from within ChaiScript itself via `set_file_reader`:
+
+```chaiscript
+// Override file loading from within a script
+set_file_reader(fun(filename) { return my_custom_read(filename) })
+```
+
+When no custom file reader is set, ChaiScript uses its built-in filesystem reader.
+
 ## Extras
 ChaiScript itself does not provide a link to the math functions defined in `<cmath>`. You can either add them yourself, or use the [ChaiScript_Extras](https://github.com/ChaiScript/ChaiScript_Extras) helper library. (Which also provides some additional string functions.)
+
+## Grammar Railroad Diagrams
+
+A formal EBNF grammar for ChaiScript is available in [`grammar/chaiscript.ebnf`](grammar/chaiscript.ebnf). You can visualize it as navigable railroad diagrams by pasting its contents into one of these tools:
+
+  * [rr — Railroad Diagram Generator (IPv6)](https://www.bottlecaps.de/rr/ui)
+  * [rr — Railroad Diagram Generator (IPv4)](https://rr.red-dove.com/ui)
+
+Open either link, switch to the **Edit Grammar** tab, paste the file contents, then click **View Diagram**.

cmake/Catch.cmake

@@ -33,6 +33,13 @@ same as the Catch name; see also ``TEST_PREFIX`` and ``TEST_SUFFIX``.
                          [TEST_SUFFIX suffix]
                          [PROPERTIES name1 value1...]
                          [TEST_LIST var]
+                         [REPORTER reporter]
+                         [OUTPUT_DIR dir]
+                         [OUTPUT_PREFIX prefix]
+                         [OUTPUT_SUFFIX suffix]
+                         [DISCOVERY_MODE <POST_BUILD|PRE_TEST>]
+                         [SKIP_IS_FAILURE]
+                         [ADD_TAGS_AS_LABELS]
     )
 
   ``catch_discover_tests`` sets up a post-build command on the test executable
@@ -90,86 +97,222 @@ same as the Catch name; see also ``TEST_PREFIX`` and ``TEST_SUFFIX``.
     executable is being used in multiple calls to ``catch_discover_tests()``.
     Note that this variable is only available in CTest.
 
+  ``REPORTER reporter``
+    Use the specified reporter when running the test case. The reporter will
+    be passed to the Catch executable as ``--reporter reporter``.
+
+  ``OUTPUT_DIR dir``
+    If specified, the parameter is passed along as
+    ``--out dir/<test_name>`` to Catch executable. The actual file name is the
+    same as the test name. This should be used instead of
+    ``EXTRA_ARGS --out foo`` to avoid race conditions writing the result output
+    when using parallel test execution.
+
+  ``OUTPUT_PREFIX prefix``
+    May be used in conjunction with ``OUTPUT_DIR``.
+    If specified, ``prefix`` is added to each output file name, like so
+    ``--out dir/prefix<test_name>``.
+
+  ``OUTPUT_SUFFIX suffix``
+    May be used in conjunction with ``OUTPUT_DIR``.
+    If specified, ``suffix`` is added to each output file name, like so
+    ``--out dir/<test_name>suffix``. This can be used to add a file extension to
+    the output e.g. ".xml".
+
+  ``DL_PATHS path...``
+    Specifies paths that need to be set for the dynamic linker to find shared
+    libraries/DLLs when running the test executable (PATH/LD_LIBRARY_PATH respectively).
+    These paths will both be set when retrieving the list of test cases from the
+    test executable and when the tests are executed themselves. This requires
+    cmake/ctest >= 3.22.
+
+  ``DL_FRAMEWORK_PATHS path...``
+    Specifies paths that need to be set for the dynamic linker to find libraries
+    packaged as frameworks on Apple platforms when running the test executable
+    (DYLD_FRAMEWORK_PATH). These paths will both be set when retrieving the list
+    of test cases from the test executable and when the tests are executed themselves.
+    This requires cmake/ctest >= 3.22.
+
+  ``DISCOVERY_MODE mode``
+    Provides control over when ``catch_discover_tests`` performs test discovery.
+    By default, ``POST_BUILD`` sets up a post-build command to perform test discovery
+    at build time. In certain scenarios, like cross-compiling, this ``POST_BUILD``
+    behavior is not desirable. By contrast, ``PRE_TEST`` delays test discovery until
+    just prior to test execution. This way test discovery occurs in the target environment
+    where the test has a better chance at finding appropriate runtime dependencies.
+
+    ``DISCOVERY_MODE`` defaults to the value of the
+    ``CMAKE_CATCH_DISCOVER_TESTS_DISCOVERY_MODE`` variable if it is not passed when
+    calling ``catch_discover_tests``. This provides a mechanism for globally selecting
+    a preferred test discovery behavior without having to modify each call site.
+
+  ``SKIP_IS_FAILURE``
+    Disables skipped test detection.
+
+  ``ADD_TAGS_AS_LABELS``
+    Adds all test tags as CTest labels.
+
 #]=======================================================================]
 
 #------------------------------------------------------------------------------
 function(catch_discover_tests TARGET)
+
   cmake_parse_arguments(
     ""
-    ""
-    "TEST_PREFIX;TEST_SUFFIX;WORKING_DIRECTORY;TEST_LIST"
-    "TEST_SPEC;EXTRA_ARGS;PROPERTIES"
+    "SKIP_IS_FAILURE;ADD_TAGS_AS_LABELS"
+    "TEST_PREFIX;TEST_SUFFIX;WORKING_DIRECTORY;TEST_LIST;REPORTER;OUTPUT_DIR;OUTPUT_PREFIX;OUTPUT_SUFFIX;DISCOVERY_MODE"
+    "TEST_SPEC;EXTRA_ARGS;PROPERTIES;DL_PATHS;DL_FRAMEWORK_PATHS"
     ${ARGN}
   )
 
+  if(${CMAKE_VERSION} VERSION_LESS "3.19")
+    message(FATAL_ERROR "This script requires JSON support from CMake version 3.19 or greater.")
+  endif()
+
   if(NOT _WORKING_DIRECTORY)
     set(_WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
   endif()
   if(NOT _TEST_LIST)
     set(_TEST_LIST ${TARGET}_TESTS)
   endif()
+  if(_DL_PATHS AND ${CMAKE_VERSION} VERSION_LESS "3.22.0")
+    message(FATAL_ERROR "The DL_PATHS option requires at least cmake 3.22")
+  endif()
+  if(_DL_FRAMEWORK_PATHS AND ${CMAKE_VERSION} VERSION_LESS "3.22.0")
+    message(FATAL_ERROR "The DL_FRAMEWORK_PATHS option requires at least cmake 3.22")
+  endif()
+  if(NOT _DISCOVERY_MODE)
+    if(NOT CMAKE_CATCH_DISCOVER_TESTS_DISCOVERY_MODE)
+      set(CMAKE_CATCH_DISCOVER_TESTS_DISCOVERY_MODE "POST_BUILD")
+    endif()
+    set(_DISCOVERY_MODE ${CMAKE_CATCH_DISCOVER_TESTS_DISCOVERY_MODE})
+  endif()
+  if(NOT _DISCOVERY_MODE MATCHES "^(POST_BUILD|PRE_TEST)$")
+    message(FATAL_ERROR "Unknown DISCOVERY_MODE: ${_DISCOVERY_MODE}")
+  endif()
 
   ## Generate a unique name based on the extra arguments
-  string(SHA1 args_hash "${_TEST_SPEC} ${_EXTRA_ARGS}")
+  string(SHA1 args_hash "${_TEST_SPEC} ${_EXTRA_ARGS} ${_REPORTER} ${_OUTPUT_DIR} ${_OUTPUT_PREFIX} ${_OUTPUT_SUFFIX}")
   string(SUBSTRING ${args_hash} 0 7 args_hash)
 
   # Define rule to generate test list for aforementioned test executable
-  set(ctest_include_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}_include-${args_hash}.cmake")
-  set(ctest_tests_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}_tests-${args_hash}.cmake")
+  set(ctest_file_base "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}-${args_hash}")
+  set(ctest_include_file "${ctest_file_base}_include.cmake")
+  set(ctest_tests_file "${ctest_file_base}_tests.cmake")
+
   get_property(crosscompiling_emulator
     TARGET ${TARGET}
     PROPERTY CROSSCOMPILING_EMULATOR
   )
-  add_custom_command(
-    TARGET ${TARGET} POST_BUILD
-    BYPRODUCTS "${ctest_tests_file}"
-    COMMAND "${CMAKE_COMMAND}"
-            -D "TEST_TARGET=${TARGET}"
-            -D "TEST_EXECUTABLE=$<TARGET_FILE:${TARGET}>"
-            -D "TEST_EXECUTOR=${crosscompiling_emulator}"
-            -D "TEST_WORKING_DIR=${_WORKING_DIRECTORY}"
-            -D "TEST_SPEC=${_TEST_SPEC}"
-            -D "TEST_EXTRA_ARGS=${_EXTRA_ARGS}"
-            -D "TEST_PROPERTIES=${_PROPERTIES}"
-            -D "TEST_PREFIX=${_TEST_PREFIX}"
-            -D "TEST_SUFFIX=${_TEST_SUFFIX}"
-            -D "TEST_LIST=${_TEST_LIST}"
-            -D "CTEST_FILE=${ctest_tests_file}"
-            -P "${_CATCH_DISCOVER_TESTS_SCRIPT}"
-    VERBATIM
-  )
+  if(NOT _SKIP_IS_FAILURE)
+    set(_PROPERTIES ${_PROPERTIES} SKIP_RETURN_CODE 4)
+  endif()
 
-  file(WRITE "${ctest_include_file}"
-    "if(EXISTS \"${ctest_tests_file}\")\n"
-    "  include(\"${ctest_tests_file}\")\n"
-    "else()\n"
-    "  add_test(${TARGET}_NOT_BUILT-${args_hash} ${TARGET}_NOT_BUILT-${args_hash})\n"
-    "endif()\n"
-  )
-
-  if(NOT ${CMAKE_VERSION} VERSION_LESS "3.10.0") 
-    # Add discovered tests to directory TEST_INCLUDE_FILES
-    set_property(DIRECTORY
-      APPEND PROPERTY TEST_INCLUDE_FILES "${ctest_include_file}"
+  if(_DISCOVERY_MODE STREQUAL "POST_BUILD")
+    add_custom_command(
+      TARGET ${TARGET} POST_BUILD
+      BYPRODUCTS "${ctest_tests_file}"
+      COMMAND "${CMAKE_COMMAND}"
+              -D "TEST_TARGET=${TARGET}"
+              -D "TEST_EXECUTABLE=$<TARGET_FILE:${TARGET}>"
+              -D "TEST_EXECUTOR=${crosscompiling_emulator}"
+              -D "TEST_WORKING_DIR=${_WORKING_DIRECTORY}"
+              -D "TEST_SPEC=${_TEST_SPEC}"
+              -D "TEST_EXTRA_ARGS=${_EXTRA_ARGS}"
+              -D "TEST_PROPERTIES=${_PROPERTIES}"
+              -D "TEST_PREFIX=${_TEST_PREFIX}"
+              -D "TEST_SUFFIX=${_TEST_SUFFIX}"
+              -D "TEST_LIST=${_TEST_LIST}"
+              -D "TEST_REPORTER=${_REPORTER}"
+              -D "TEST_OUTPUT_DIR=${_OUTPUT_DIR}"
+              -D "TEST_OUTPUT_PREFIX=${_OUTPUT_PREFIX}"
+              -D "TEST_OUTPUT_SUFFIX=${_OUTPUT_SUFFIX}"
+              -D "TEST_DL_PATHS=${_DL_PATHS}"
+              -D "TEST_DL_FRAMEWORK_PATHS=${_DL_FRAMEWORK_PATHS}"
+              -D "CTEST_FILE=${ctest_tests_file}"
+              -D "ADD_TAGS_AS_LABELS=${_ADD_TAGS_AS_LABELS}"
+              -P "${_CATCH_DISCOVER_TESTS_SCRIPT}"
+      VERBATIM
     )
-  else()
-    # Add discovered tests as directory TEST_INCLUDE_FILE if possible
-    get_property(test_include_file_set DIRECTORY PROPERTY TEST_INCLUDE_FILE SET)
-    if (NOT ${test_include_file_set})
-      set_property(DIRECTORY
-        PROPERTY TEST_INCLUDE_FILE "${ctest_include_file}"
+
+    file(WRITE "${ctest_include_file}"
+      "if(EXISTS \"${ctest_tests_file}\")\n"
+      "  include(\"${ctest_tests_file}\")\n"
+      "else()\n"
+      "  add_test(${TARGET}_NOT_BUILT-${args_hash} ${TARGET}_NOT_BUILT-${args_hash})\n"
+      "endif()\n"
+    )
+
+  elseif(_DISCOVERY_MODE STREQUAL "PRE_TEST")
+
+    get_property(GENERATOR_IS_MULTI_CONFIG GLOBAL
+        PROPERTY GENERATOR_IS_MULTI_CONFIG
+    )
+
+    if(GENERATOR_IS_MULTI_CONFIG)
+      set(ctest_tests_file "${ctest_file_base}_tests-$<CONFIG>.cmake")
+    endif()
+
+    string(CONCAT ctest_include_content
+      "if(EXISTS \"$<TARGET_FILE:${TARGET}>\")"                                    "\n"
+      "  if(NOT EXISTS \"${ctest_tests_file}\" OR"                                 "\n"
+      "     NOT \"${ctest_tests_file}\" IS_NEWER_THAN \"$<TARGET_FILE:${TARGET}>\" OR\n"
+      "     NOT \"${ctest_tests_file}\" IS_NEWER_THAN \"\${CMAKE_CURRENT_LIST_FILE}\")\n"
+      "    include(\"${_CATCH_DISCOVER_TESTS_SCRIPT}\")"                           "\n"
+      "    catch_discover_tests_impl("                                             "\n"
+      "      TEST_EXECUTABLE"        " [==[" "$<TARGET_FILE:${TARGET}>"   "]==]"   "\n"
+      "      TEST_EXECUTOR"          " [==[" "${crosscompiling_emulator}" "]==]"   "\n"
+      "      TEST_WORKING_DIR"       " [==[" "${_WORKING_DIRECTORY}"      "]==]"   "\n"
+      "      TEST_SPEC"              " [==[" "${_TEST_SPEC}"              "]==]"   "\n"
+      "      TEST_EXTRA_ARGS"        " [==[" "${_EXTRA_ARGS}"             "]==]"   "\n"
+      "      TEST_PROPERTIES"        " [==[" "${_PROPERTIES}"             "]==]"   "\n"
+      "      TEST_PREFIX"            " [==[" "${_TEST_PREFIX}"            "]==]"   "\n"
+      "      TEST_SUFFIX"            " [==[" "${_TEST_SUFFIX}"            "]==]"   "\n"
+      "      TEST_LIST"              " [==[" "${_TEST_LIST}"              "]==]"   "\n"
+      "      TEST_REPORTER"          " [==[" "${_REPORTER}"               "]==]"   "\n"
+      "      TEST_OUTPUT_DIR"        " [==[" "${_OUTPUT_DIR}"             "]==]"   "\n"
+      "      TEST_OUTPUT_PREFIX"     " [==[" "${_OUTPUT_PREFIX}"          "]==]"   "\n"
+      "      TEST_OUTPUT_SUFFIX"     " [==[" "${_OUTPUT_SUFFIX}"          "]==]"   "\n"
+      "      CTEST_FILE"             " [==[" "${ctest_tests_file}"        "]==]"   "\n"
+      "      TEST_DL_PATHS"          " [==[" "${_DL_PATHS}"               "]==]"   "\n"
+      "      TEST_DL_FRAMEWORK_PATHS" " [==[" "${_DL_FRAMEWORK_PATHS}"     "]==]"   "\n"
+      "      ADD_TAGS_AS_LABELS"     " [==[" "${_ADD_TAGS_AS_LABELS}"     "]==]"   "\n"
+      "    )"                                                                      "\n"
+      "  endif()"                                                                  "\n"
+      "  include(\"${ctest_tests_file}\")"                                         "\n"
+      "else()"                                                                     "\n"
+      "  add_test(${TARGET}_NOT_BUILT ${TARGET}_NOT_BUILT)"                        "\n"
+      "endif()"                                                                    "\n"
+    )
+
+    if(GENERATOR_IS_MULTI_CONFIG)
+      foreach(_config ${CMAKE_CONFIGURATION_TYPES})
+        file(GENERATE OUTPUT "${ctest_file_base}_include-${_config}.cmake" CONTENT "${ctest_include_content}" CONDITION $<CONFIG:${_config}>)
+      endforeach()
+      string(CONCAT ctest_include_multi_content
+        "if(NOT CTEST_CONFIGURATION_TYPE)"                                              "\n"
+        "  message(\"No configuration for testing specified, use '-C <cfg>'.\")"        "\n"
+        "else()"                                                                        "\n"
+        "  include(\"${ctest_file_base}_include-\${CTEST_CONFIGURATION_TYPE}.cmake\")"  "\n"
+        "endif()"                                                                       "\n"
       )
+      file(GENERATE OUTPUT "${ctest_include_file}" CONTENT "${ctest_include_multi_content}")
     else()
-      message(FATAL_ERROR
-        "Cannot set more than one TEST_INCLUDE_FILE"
-      )
+      file(GENERATE OUTPUT "${ctest_file_base}_include.cmake" CONTENT "${ctest_include_content}")
+      file(WRITE "${ctest_include_file}" "include(\"${ctest_file_base}_include.cmake\")")
     endif()
   endif()
 
+  # Add discovered tests to directory TEST_INCLUDE_FILES
+  set_property(DIRECTORY
+    APPEND PROPERTY TEST_INCLUDE_FILES "${ctest_include_file}"
+  )
+
 endfunction()
 
 ###############################################################################
 
 set(_CATCH_DISCOVER_TESTS_SCRIPT
   ${CMAKE_CURRENT_LIST_DIR}/CatchAddTests.cmake
+  CACHE INTERNAL "Catch2 full path to CatchAddTests.cmake helper file"
 )

cmake/CatchAddTests.cmake

@@ -1,18 +1,12 @@
 # Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
 # file Copyright.txt or https://cmake.org/licensing for details.
 
-set(prefix "${TEST_PREFIX}")
-set(suffix "${TEST_SUFFIX}")
-set(spec ${TEST_SPEC})
-set(extra_args ${TEST_EXTRA_ARGS})
-set(properties ${TEST_PROPERTIES})
-set(script)
-set(suite)
-set(tests)
-
 function(add_command NAME)
   set(_args "")
-  foreach(_arg ${ARGN})
+  # use ARGV* instead of ARGN, because ARGN splits arrays into multiple arguments
+  math(EXPR _last_arg ${ARGC}-1)
+  foreach(_n RANGE 1 ${_last_arg})
+    set(_arg "${ARGV${_n}}")
     if(_arg MATCHES "[^-./:a-zA-Z0-9_]")
       set(_args "${_args} [==[${_arg}]==]") # form a bracket_argument
     else()
@@ -22,55 +16,239 @@ function(add_command NAME)
   set(script "${script}${NAME}(${_args})\n" PARENT_SCOPE)
 endfunction()
 
-# Run test executable to get list of available tests
-if(NOT EXISTS "${TEST_EXECUTABLE}")
-  message(FATAL_ERROR
-    "Specified test executable '${TEST_EXECUTABLE}' does not exist"
+function(catch_discover_tests_impl)
+
+  cmake_parse_arguments(
+    ""
+    ""
+    "TEST_EXECUTABLE;TEST_WORKING_DIR;TEST_OUTPUT_DIR;TEST_OUTPUT_PREFIX;TEST_OUTPUT_SUFFIX;TEST_PREFIX;TEST_REPORTER;TEST_SPEC;TEST_SUFFIX;TEST_LIST;CTEST_FILE"
+    "TEST_EXTRA_ARGS;TEST_PROPERTIES;TEST_EXECUTOR;TEST_DL_PATHS;TEST_DL_FRAMEWORK_PATHS;ADD_TAGS_AS_LABELS"
+    ${ARGN}
+  )
+
+  set(add_tags "${_ADD_TAGS_AS_LABELS}")
+  set(prefix "${_TEST_PREFIX}")
+  set(suffix "${_TEST_SUFFIX}")
+  set(spec ${_TEST_SPEC})
+  set(extra_args ${_TEST_EXTRA_ARGS})
+  set(properties ${_TEST_PROPERTIES})
+  set(reporter ${_TEST_REPORTER})
+  set(output_dir ${_TEST_OUTPUT_DIR})
+  set(output_prefix ${_TEST_OUTPUT_PREFIX})
+  set(output_suffix ${_TEST_OUTPUT_SUFFIX})
+  set(dl_paths ${_TEST_DL_PATHS})
+  set(dl_framework_paths ${_TEST_DL_FRAMEWORK_PATHS})
+  set(environment_modifications "")
+  set(script)
+  set(suite)
+  set(tests)
+
+  if(WIN32)
+    set(dl_paths_variable_name PATH)
+  elseif(APPLE)
+    set(dl_paths_variable_name DYLD_LIBRARY_PATH)
+  else()
+    set(dl_paths_variable_name LD_LIBRARY_PATH)
+  endif()
+
+  # Run test executable to get list of available tests
+  if(NOT EXISTS "${_TEST_EXECUTABLE}")
+    message(FATAL_ERROR
+      "Specified test executable '${_TEST_EXECUTABLE}' does not exist"
+    )
+  endif()
+
+  if(dl_paths)
+    cmake_path(CONVERT "$ENV{${dl_paths_variable_name}}" TO_NATIVE_PATH_LIST env_dl_paths)
+    list(PREPEND env_dl_paths "${dl_paths}")
+    cmake_path(CONVERT "${env_dl_paths}" TO_NATIVE_PATH_LIST paths)
+    set(ENV{${dl_paths_variable_name}} "${paths}")
+  endif()
+
+  if(APPLE AND dl_framework_paths)
+    cmake_path(CONVERT "$ENV{DYLD_FRAMEWORK_PATH}" TO_NATIVE_PATH_LIST env_dl_framework_paths)
+    list(PREPEND env_dl_framework_paths "${dl_framework_paths}")
+    cmake_path(CONVERT "${env_dl_framework_paths}" TO_NATIVE_PATH_LIST paths)
+    set(ENV{DYLD_FRAMEWORK_PATH} "${paths}")
+  endif()
+
+  execute_process(
+    COMMAND ${_TEST_EXECUTOR} "${_TEST_EXECUTABLE}" ${spec} --list-tests --reporter json
+    OUTPUT_VARIABLE listing_output
+    RESULT_VARIABLE result
+    WORKING_DIRECTORY "${_TEST_WORKING_DIR}"
+  )
+  if(NOT ${result} EQUAL 0)
+    message(FATAL_ERROR
+      "Error listing tests from executable '${_TEST_EXECUTABLE}':\n"
+      "  Result: ${result}\n"
+      "  Output: ${listing_output}\n"
+    )
+  endif()
+
+  # Prepare reporter
+  if(reporter)
+    set(reporter_arg "--reporter ${reporter}")
+
+    # Run test executable to check whether reporter is available
+    # note that the use of --list-reporters is not the important part,
+    # we only want to check whether the execution succeeds with ${reporter_arg}
+    execute_process(
+      COMMAND ${_TEST_EXECUTOR} "${_TEST_EXECUTABLE}" ${spec} ${reporter_arg} --list-reporters
+      OUTPUT_VARIABLE reporter_check_output
+      RESULT_VARIABLE reporter_check_result
+      WORKING_DIRECTORY "${_TEST_WORKING_DIR}"
+    )
+    if(${reporter_check_result} EQUAL 255)
+      message(FATAL_ERROR
+        "\"${reporter}\" is not a valid reporter!\n"
+      )
+    elseif(NOT ${reporter_check_result} EQUAL 0)
+      message(FATAL_ERROR
+        "Error checking for reporter in test executable '${_TEST_EXECUTABLE}':\n"
+        "  Result: ${reporter_check_result}\n"
+        "  Output: ${reporter_check_output}\n"
+      )
+    endif()
+  endif()
+
+  # Prepare output dir
+  if(output_dir AND NOT IS_ABSOLUTE ${output_dir})
+    set(output_dir "${_TEST_WORKING_DIR}/${output_dir}")
+    if(NOT EXISTS ${output_dir})
+      file(MAKE_DIRECTORY ${output_dir})
+    endif()
+  endif()
+
+  if(dl_paths)
+    foreach(path ${dl_paths})
+      cmake_path(NATIVE_PATH path native_path)
+      list(PREPEND environment_modifications "${dl_paths_variable_name}=path_list_prepend:${native_path}")
+    endforeach()
+  endif()
+
+  if(APPLE AND dl_framework_paths)
+    foreach(path ${dl_framework_paths})
+      cmake_path(NATIVE_PATH path native_path)
+      list(PREPEND environment_modifications "DYLD_FRAMEWORK_PATH=path_list_prepend:${native_path}")
+    endforeach()
+  endif()
+
+  # Parse JSON output for list of tests/class names/tags
+  string(JSON version GET "${listing_output}" "version")
+  if(NOT version STREQUAL "1")
+    message(FATAL_ERROR "Unsupported catch output version: '${version}'")
+  endif()
+
+  # Speed-up reparsing by cutting away unneeded parts of JSON.
+  string(JSON test_listing GET "${listing_output}" "listings" "tests")
+  string(JSON num_tests LENGTH "${test_listing}")
+
+  # Exit early if no tests are detected
+  if(num_tests STREQUAL "0")
+    file(WRITE "${_CTEST_FILE}" "")
+    return()
+  endif()
+
+  # CMake's foreach-RANGE is inclusive, so we have to subtract 1
+  math(EXPR num_tests "${num_tests} - 1")
+
+  foreach(idx RANGE ${num_tests})
+    string(JSON single_test GET ${test_listing} ${idx})
+    string(JSON test_tags GET "${single_test}" "tags")
+    string(JSON plain_name GET "${single_test}" "name")
+
+    # Escape characters in test case names that would be parsed by Catch2
+    # Note that the \ escaping must happen FIRST! Do not change the order.
+    set(escaped_name "${plain_name}")
+    foreach(char \\ , [ ] ;)
+      string(REPLACE ${char} "\\${char}" escaped_name "${escaped_name}")
+    endforeach(char)
+    # ...add output dir
+    if(output_dir)
+      string(REGEX REPLACE "[^A-Za-z0-9_]" "_" escaped_name_clean "${escaped_name}")
+      set(output_dir_arg "--out ${output_dir}/${output_prefix}${escaped_name_clean}${output_suffix}")
+    endif()
+
+    # ...and add to script
+    add_command(add_test
+      "${prefix}${plain_name}${suffix}"
+      ${_TEST_EXECUTOR}
+      "${_TEST_EXECUTABLE}"
+      "${escaped_name}"
+      ${extra_args}
+      "${reporter_arg}"
+      "${output_dir_arg}"
+    )
+    add_command(set_tests_properties
+      "${prefix}${plain_name}${suffix}"
+      PROPERTIES
+      WORKING_DIRECTORY "${_TEST_WORKING_DIR}"
+      ${properties}
+    )
+
+    if(add_tags)
+      string(JSON num_tags LENGTH "${test_tags}")
+      math(EXPR num_tags "${num_tags} - 1")
+      set(tag_list "")
+      if(num_tags GREATER_EQUAL "0")
+        foreach(tag_idx RANGE ${num_tags})
+          string(JSON a_tag GET "${test_tags}" "${tag_idx}")
+          # Catch2's tags can contain semicolons, which are list element separators
+          # in CMake, so we have to escape them. Ideally we could use the [=[...]=]
+          # syntax for this, but CTest currently keeps the square quotes in the label
+          # name. So we add 2 backslashes to escape it instead.
+          # **IMPORTANT**: The number of backslashes depends on how many layers
+          #                of CMake the tag goes. If this script is changed, the
+          #                number of backslashes to escape may change as well.
+          string(REPLACE ";" "\\;" a_tag "${a_tag}")
+          list(APPEND tag_list "${a_tag}")
+        endforeach()
+
+        add_command(set_tests_properties
+          "${prefix}${plain_name}${suffix}"
+          PROPERTIES
+          LABELS "${tag_list}"
+        )
+      endif()
+    endif(add_tags)
+
+    if(environment_modifications)
+      add_command(set_tests_properties
+        "${prefix}${plain_name}${suffix}"
+        PROPERTIES
+        ENVIRONMENT_MODIFICATION "${environment_modifications}")
+    endif()
+
+    list(APPEND tests "${prefix}${plain_name}${suffix}")
+  endforeach()
+
+  # Create a list of all discovered tests, which users may use to e.g. set
+  # properties on the tests
+  add_command(set ${_TEST_LIST} ${tests})
+
+  # Write CTest script
+  file(WRITE "${_CTEST_FILE}" "${script}")
+endfunction()
+
+if(CMAKE_SCRIPT_MODE_FILE)
+  catch_discover_tests_impl(
+    TEST_EXECUTABLE ${TEST_EXECUTABLE}
+    TEST_EXECUTOR ${TEST_EXECUTOR}
+    TEST_WORKING_DIR ${TEST_WORKING_DIR}
+    TEST_SPEC ${TEST_SPEC}
+    TEST_EXTRA_ARGS ${TEST_EXTRA_ARGS}
+    TEST_PROPERTIES ${TEST_PROPERTIES}
+    TEST_PREFIX ${TEST_PREFIX}
+    TEST_SUFFIX ${TEST_SUFFIX}
+    TEST_LIST ${TEST_LIST}
+    TEST_REPORTER ${TEST_REPORTER}
+    TEST_OUTPUT_DIR ${TEST_OUTPUT_DIR}
+    TEST_OUTPUT_PREFIX ${TEST_OUTPUT_PREFIX}
+    TEST_OUTPUT_SUFFIX ${TEST_OUTPUT_SUFFIX}
+    TEST_DL_PATHS ${TEST_DL_PATHS}
+    TEST_DL_FRAMEWORK_PATHS ${TEST_DL_FRAMEWORK_PATHS}
+    CTEST_FILE ${CTEST_FILE}
+    ADD_TAGS_AS_LABELS ${ADD_TAGS_AS_LABELS}
   )
 endif()
-execute_process(
-  COMMAND ${TEST_EXECUTOR} "${TEST_EXECUTABLE}" ${spec} --list-test-names-only
-  OUTPUT_VARIABLE output
-  RESULT_VARIABLE result
-)
-# Catch --list-test-names-only reports the number of tests, so 0 is... surprising
-if(${result} EQUAL 0)
-  message(WARNING
-    "Test executable '${TEST_EXECUTABLE}' contains no tests!\n"
-  )
-elseif(${result} LESS 0)
-  message(FATAL_ERROR
-    "Error running test executable '${TEST_EXECUTABLE}':\n"
-    "  Result: ${result}\n"
-    "  Output: ${output}\n"
-  )
-endif()
-
-string(REPLACE "\n" ";" output "${output}")
-
-# Parse output
-foreach(line ${output})
-  set(test ${line})
-  # ...and add to script
-  add_command(add_test
-    "${prefix}${test}${suffix}"
-    ${TEST_EXECUTOR}
-    "${TEST_EXECUTABLE}"
-    ${test}
-    ${extra_args}
-  )
-  add_command(set_tests_properties
-    "${prefix}${test}${suffix}"
-    PROPERTIES
-    WORKING_DIRECTORY "${TEST_WORKING_DIR}"
-    ${properties}
-  )
-  list(APPEND tests "${prefix}${test}${suffix}")
-endforeach()
-
-# Create a list of all discovered tests, which users may use to e.g. set
-# properties on the tests
-add_command(set ${TEST_LIST} ${tests})
-
-# Write CTest script
-file(WRITE "${CTEST_FILE}" "${script}")

cmake/CatchShardTests.cmake

@@ -0,0 +1,72 @@
+
+#              Copyright Catch2 Authors
+# Distributed under the Boost Software License, Version 1.0.
+#   (See accompanying file LICENSE.txt or copy at
+#        https://www.boost.org/LICENSE_1_0.txt)
+
+# SPDX-License-Identifier: BSL-1.0
+
+# Supported optional args:
+#  * SHARD_COUNT - number of shards to split target's tests into
+#  * REPORTER    - reporter spec to use for tests
+#  * TEST_SPEC   - test spec used for filtering tests
+function(catch_add_sharded_tests TARGET)
+  if(${CMAKE_VERSION} VERSION_LESS "3.10.0")
+    message(FATAL_ERROR "add_sharded_catch_tests only supports CMake versions 3.10.0 and up")
+  endif()
+
+  cmake_parse_arguments(
+    ""
+    ""
+    "SHARD_COUNT;REPORTER;TEST_SPEC"
+    ""
+    ${ARGN}
+  )
+  
+  if(NOT DEFINED _SHARD_COUNT)
+    set(_SHARD_COUNT 2)
+  endif()
+
+  # Generate a unique name based on the extra arguments
+  string(SHA1 args_hash "${_TEST_SPEC} ${_EXTRA_ARGS} ${_REPORTER} ${_OUTPUT_DIR} ${_OUTPUT_PREFIX} ${_OUTPUT_SUFFIX} ${_SHARD_COUNT}")
+  string(SUBSTRING ${args_hash} 0 7 args_hash)
+
+  set(ctest_include_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}-sharded-tests-include-${args_hash}.cmake")
+  set(ctest_tests_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}-sharded-tests-impl-${args_hash}.cmake")
+
+  file(WRITE "${ctest_include_file}"
+    "if(EXISTS \"${ctest_tests_file}\")\n"
+    "  include(\"${ctest_tests_file}\")\n"
+    "else()\n"
+    "  add_test(${TARGET}_NOT_BUILT-${args_hash} ${TARGET}_NOT_BUILT-${args_hash})\n"
+    "endif()\n"
+  )
+
+  set_property(DIRECTORY
+    APPEND PROPERTY TEST_INCLUDE_FILES "${ctest_include_file}"
+  )
+
+  set(shard_impl_script_file "${_CATCH_DISCOVER_SHARD_TESTS_IMPL_SCRIPT}")
+
+  add_custom_command(
+    TARGET ${TARGET} POST_BUILD
+    BYPRODUCTS "${ctest_tests_file}"
+    COMMAND "${CMAKE_COMMAND}"
+            -D "TARGET_NAME=${TARGET}"
+            -D "TEST_BINARY=$<TARGET_FILE:${TARGET}>"
+            -D "CTEST_FILE=${ctest_tests_file}"
+            -D "SHARD_COUNT=${_SHARD_COUNT}"
+            -D "REPORTER_SPEC=${_REPORTER}"
+            -D "TEST_SPEC=${_TEST_SPEC}"
+            -P "${shard_impl_script_file}"
+    VERBATIM
+  )
+endfunction()
+
+
+###############################################################################
+
+set(_CATCH_DISCOVER_SHARD_TESTS_IMPL_SCRIPT
+    ${CMAKE_CURRENT_LIST_DIR}/CatchShardTestsImpl.cmake
+  CACHE INTERNAL "Catch2 full path to CatchShardTestsImpl.cmake helper file"
+)

cmake/CatchShardTestsImpl.cmake

@@ -0,0 +1,52 @@
+
+#              Copyright Catch2 Authors
+# Distributed under the Boost Software License, Version 1.0.
+#   (See accompanying file LICENSE.txt or copy at
+#        https://www.boost.org/LICENSE_1_0.txt)
+
+# SPDX-License-Identifier: BSL-1.0
+
+# Indirection for CatchShardTests that allows us to delay the script
+# file generation until build time.
+
+# Expected args:
+#  * TEST_BINARY - full path to the test binary to run sharded
+#  * CTEST_FILE  - full path to ctest script file to write to
+#  * TARGET_NAME - name of the target to shard (used for test names)
+#  * SHARD_COUNT - number of shards to split the binary into
+# Optional args:
+#  * REPORTER_SPEC - reporter specs to be passed down to the binary
+#  * TEST_SPEC     - test spec to pass down to the test binary
+
+if(NOT EXISTS "${TEST_BINARY}")
+  message(FATAL_ERROR
+    "Specified test binary '${TEST_BINARY}' does not exist"
+  )
+endif()
+
+set(other_args "")
+if(TEST_SPEC)
+  set(other_args "${other_args} ${TEST_SPEC}")
+endif()
+if(REPORTER_SPEC)
+  set(other_args "${other_args} --reporter ${REPORTER_SPEC}")
+endif()
+
+# foreach RANGE in cmake is inclusive of the end, so we have to adjust it
+math(EXPR adjusted_shard_count "${SHARD_COUNT} - 1")
+
+file(WRITE "${CTEST_FILE}"
+  "string(RANDOM LENGTH 8 ALPHABET \"0123456789abcdef\" rng_seed)\n"
+  "\n"
+  "foreach(shard_idx RANGE ${adjusted_shard_count})\n"
+  "  add_test(${TARGET_NAME}-shard-" [[${shard_idx}]] "/${adjusted_shard_count}\n"
+  "    ${TEST_BINARY}"
+  " --shard-index " [[${shard_idx}]]
+  " --shard-count ${SHARD_COUNT}"
+  " --rng-seed " [[0x${rng_seed}]]
+  " --order rand"
+  "${other_args}"
+  "\n"
+  "  )\n"
+  "endforeach()\n"
+)

cmake/ParseAndAddCatchTests.cmake

@@ -1,9 +1,11 @@
 #==================================================================================================#
 #  supported macros                                                                                #
 #    - TEST_CASE,                                                                                  #
+#    - TEMPLATE_TEST_CASE                                                                          #
 #    - SCENARIO,                                                                                   #
 #    - TEST_CASE_METHOD,                                                                           #
 #    - CATCH_TEST_CASE,                                                                            #
+#    - CATCH_TEMPLATE_TEST_CASE                                                                    #
 #    - CATCH_SCENARIO,                                                                             #
 #    - CATCH_TEST_CASE_METHOD.                                                                     #
 #                                                                                                  #
@@ -39,9 +41,24 @@
 #    PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS (Default OFF)                                      #
 #    -- causes CMake to rerun when file with tests changes so that new tests will be discovered    #
 #                                                                                                  #
+# One can also set (locally) the optional variable OptionalCatchTestLauncher to precise the way    #
+# a test should be run. For instance to use test MPI, one can write                                #
+#     set(OptionalCatchTestLauncher ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${NUMPROC})                 #
+# just before calling this ParseAndAddCatchTests function                                          #
+#                                                                                                  #
+# The AdditionalCatchParameters optional variable can be used to pass extra argument to the test   #
+# command. For example, to include successful tests in the output, one can write                   #
+#     set(AdditionalCatchParameters --success)                                                     #
+#                                                                                                  #
+# After the script, the ParseAndAddCatchTests_TESTS property for the target, and for each source   #
+# file in the target is set, and contains the list of the tests extracted from that target, or     #
+# from that file. This is useful, for example to add further labels or properties to the tests.    #
+#                                                                                                  #
 #==================================================================================================#
 
-cmake_minimum_required(VERSION 2.8.8)
+if(CMAKE_MINIMUM_REQUIRED_VERSION VERSION_LESS 2.8.8)
+  message(FATAL_ERROR "ParseAndAddCatchTests requires CMake 2.8.8 or newer")
+endif()
 
 option(PARSE_CATCH_TESTS_VERBOSE "Print Catch to CTest parser debug messages" OFF)
 option(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS "Exclude tests with [!hide], [.] or [.foo] tags" OFF)
@@ -49,10 +66,10 @@ option(PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME "Add fixture class name to the
 option(PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME "Add target name to the test name" ON)
 option(PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS "Add test file to CMAKE_CONFIGURE_DEPENDS property" OFF)
 
-function(PrintDebugMessage)
-    if(PARSE_CATCH_TESTS_VERBOSE)
-            message(STATUS "ParseAndAddCatchTests: ${ARGV}")
-    endif()
+function(ParseAndAddCatchTests_PrintDebugMessage)
+  if(PARSE_CATCH_TESTS_VERBOSE)
+    message(STATUS "ParseAndAddCatchTests: ${ARGV}")
+  endif()
 endfunction()
 
 # This removes the contents between
@@ -60,7 +77,7 @@ endfunction()
 #  - full line comments (i.e. // ... )
 # contents have been read into '${CppCode}'.
 # !keep partial line comments
-function(RemoveComments CppCode)
+function(ParseAndAddCatchTests_RemoveComments CppCode)
   string(ASCII 2 CMakeBeginBlockComment)
   string(ASCII 3 CMakeEndBlockComment)
   string(REGEX REPLACE "/\\*" "${CMakeBeginBlockComment}" ${CppCode} "${${CppCode}}")
@@ -72,114 +89,162 @@ function(RemoveComments CppCode)
 endfunction()
 
 # Worker function
-function(ParseFile SourceFile TestTarget)
-    # According to CMake docs EXISTS behavior is well-defined only for full paths.
-    get_filename_component(SourceFile ${SourceFile} ABSOLUTE)
-    if(NOT EXISTS ${SourceFile})
-        message(WARNING "Cannot find source file: ${SourceFile}")
-        return()
+function(ParseAndAddCatchTests_ParseFile SourceFile TestTarget)
+  # If SourceFile is an object library, do not scan it (as it is not a file). Exit without giving a warning about a missing file.
+  if(SourceFile MATCHES "\\\$<TARGET_OBJECTS:.+>")
+    ParseAndAddCatchTests_PrintDebugMessage("Detected OBJECT library: ${SourceFile} this will not be scanned for tests.")
+    return()
+  endif()
+  # According to CMake docs EXISTS behavior is well-defined only for full paths.
+  get_filename_component(SourceFile ${SourceFile} ABSOLUTE)
+  if(NOT EXISTS ${SourceFile})
+    message(WARNING "Cannot find source file: ${SourceFile}")
+    return()
+  endif()
+  ParseAndAddCatchTests_PrintDebugMessage("parsing ${SourceFile}")
+  file(STRINGS ${SourceFile} Contents NEWLINE_CONSUME)
+
+  # Remove block and fullline comments
+  ParseAndAddCatchTests_RemoveComments(Contents)
+
+  # Find definition of test names
+  # https://regex101.com/r/JygOND/1
+  string(REGEX MATCHALL "[ \t]*(CATCH_)?(TEMPLATE_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)[ \t]*\\([ \t\n]*\"[^\"]*\"[ \t\n]*(,[ \t\n]*\"[^\"]*\")?(,[ \t\n]*[^\,\)]*)*\\)[ \t\n]*\{+[ \t]*(//[^\n]*[Tt][Ii][Mm][Ee][Oo][Uu][Tt][ \t]*[0-9]+)*" Tests "${Contents}")
+
+  if(PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS AND Tests)
+    ParseAndAddCatchTests_PrintDebugMessage("Adding ${SourceFile} to CMAKE_CONFIGURE_DEPENDS property")
+    set_property(
+      DIRECTORY
+      APPEND
+      PROPERTY CMAKE_CONFIGURE_DEPENDS ${SourceFile}
+    )
+  endif()
+
+  # check CMP0110 policy for new add_test() behavior
+  if(POLICY CMP0110)
+    cmake_policy(GET CMP0110 _cmp0110_value) # new add_test() behavior
+  else()
+    # just to be thorough explicitly set the variable
+    set(_cmp0110_value)
+  endif()
+
+  foreach(TestName ${Tests})
+    # Strip newlines
+    string(REGEX REPLACE "\\\\\n|\n" "" TestName "${TestName}")
+
+    # Get test type and fixture if applicable
+    string(REGEX MATCH "(CATCH_)?(TEMPLATE_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)[ \t]*\\([^,^\"]*" TestTypeAndFixture "${TestName}")
+    string(REGEX MATCH "(CATCH_)?(TEMPLATE_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)" TestType "${TestTypeAndFixture}")
+    string(REGEX REPLACE "${TestType}\\([ \t]*" "" TestFixture "${TestTypeAndFixture}")
+
+    # Get string parts of test definition
+    string(REGEX MATCHALL "\"+([^\\^\"]|\\\\\")+\"+" TestStrings "${TestName}")
+
+    # Strip wrapping quotation marks
+    string(REGEX REPLACE "^\"(.*)\"$" "\\1" TestStrings "${TestStrings}")
+    string(REPLACE "\";\"" ";" TestStrings "${TestStrings}")
+
+    # Validate that a test name and tags have been provided
+    list(LENGTH TestStrings TestStringsLength)
+    if(TestStringsLength GREATER 2 OR TestStringsLength LESS 1)
+      message(FATAL_ERROR "You must provide a valid test name and tags for all tests in ${SourceFile}")
     endif()
-    PrintDebugMessage("parsing ${SourceFile}")
-    file(STRINGS ${SourceFile} Contents NEWLINE_CONSUME)
 
-    # Remove block and fullline comments
-    RemoveComments(Contents)
+    # Assign name and tags
+    list(GET TestStrings 0 Name)
+    if("${TestType}" STREQUAL "SCENARIO")
+      set(Name "Scenario: ${Name}")
+    endif()
+    if(PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME AND "${TestType}" MATCHES "(CATCH_)?TEST_CASE_METHOD" AND TestFixture)
+      set(CTestName "${TestFixture}:${Name}")
+    else()
+      set(CTestName "${Name}")
+    endif()
+    if(PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME)
+      set(CTestName "${TestTarget}:${CTestName}")
+    endif()
+    # add target to labels to enable running all tests added from this target
+    set(Labels ${TestTarget})
+    if(TestStringsLength EQUAL 2)
+      list(GET TestStrings 1 Tags)
+      string(TOLOWER "${Tags}" Tags)
+      # remove target from labels if the test is hidden
+      if("${Tags}" MATCHES ".*\\[!?(hide|\\.)\\].*")
+        list(REMOVE_ITEM Labels ${TestTarget})
+      endif()
+      string(REPLACE "]" ";" Tags "${Tags}")
+      string(REPLACE "[" "" Tags "${Tags}")
+    else()
+      # unset tags variable from previous loop
+      unset(Tags)
+    endif()
 
-    # Find definition of test names
-    string(REGEX MATCHALL "[ \t]*(CATCH_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)[ \t]*\\([^\)]+\\)+[ \t\n]*{+[ \t]*(//[^\n]*[Tt][Ii][Mm][Ee][Oo][Uu][Tt][ \t]*[0-9]+)*" Tests "${Contents}")
+    list(APPEND Labels ${Tags})
 
-    if(PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS AND Tests)
-      PrintDebugMessage("Adding ${SourceFile} to CMAKE_CONFIGURE_DEPENDS property")
+    set(HiddenTagFound OFF)
+    foreach(label ${Labels})
+      string(REGEX MATCH "^!hide|^\\." result ${label})
+      if(result)
+        set(HiddenTagFound ON)
+        break()
+      endif()
+    endforeach(label)
+    if(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS AND ${HiddenTagFound} AND ${CMAKE_VERSION} VERSION_LESS "3.9")
+      ParseAndAddCatchTests_PrintDebugMessage("Skipping test \"${CTestName}\" as it has [!hide], [.] or [.foo] label")
+    else()
+      ParseAndAddCatchTests_PrintDebugMessage("Adding test \"${CTestName}\"")
+      if(Labels)
+        ParseAndAddCatchTests_PrintDebugMessage("Setting labels to ${Labels}")
+      endif()
+
+      # Escape commas in the test spec
+      string(REPLACE "," "\\," Name ${Name})
+
+      # Work around CMake 3.18.0 change in `add_test()`, before the escaped quotes were necessary,
+      # only with CMake 3.18.0 the escaped double quotes confuse the call. This change is reverted in 3.18.1
+      # And properly introduced in 3.19 with the CMP0110 policy
+      if(_cmp0110_value STREQUAL "NEW" OR ${CMAKE_VERSION} VERSION_EQUAL "3.18")
+        ParseAndAddCatchTests_PrintDebugMessage("CMP0110 set to NEW, no need for add_test(\"\") workaround")
+      else()
+        ParseAndAddCatchTests_PrintDebugMessage("CMP0110 set to OLD adding \"\" for add_test() workaround")
+        set(CTestName "\"${CTestName}\"")
+      endif()
+
+      # Handle template test cases
+      if("${TestTypeAndFixture}" MATCHES ".*TEMPLATE_.*")
+        set(Name "${Name} - *")
+      endif()
+
+      # Add the test and set its properties
+      add_test(NAME "${CTestName}" COMMAND ${OptionalCatchTestLauncher} $<TARGET_FILE:${TestTarget}> ${Name} ${AdditionalCatchParameters})
+      # Old CMake versions do not document VERSION_GREATER_EQUAL, so we use VERSION_GREATER with 3.8 instead
+      if(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS AND ${HiddenTagFound} AND ${CMAKE_VERSION} VERSION_GREATER "3.8")
+        ParseAndAddCatchTests_PrintDebugMessage("Setting DISABLED test property")
+        set_tests_properties("${CTestName}" PROPERTIES DISABLED ON)
+      else()
+        set_tests_properties("${CTestName}" PROPERTIES FAIL_REGULAR_EXPRESSION "No tests ran"
+                                                LABELS "${Labels}")
+      endif()
       set_property(
-        DIRECTORY
+        TARGET ${TestTarget}
         APPEND
-        PROPERTY CMAKE_CONFIGURE_DEPENDS ${SourceFile}
-      )
+        PROPERTY ParseAndAddCatchTests_TESTS "${CTestName}")
+      set_property(
+        SOURCE ${SourceFile}
+        APPEND
+        PROPERTY ParseAndAddCatchTests_TESTS "${CTestName}")
     endif()
-
-    foreach(TestName ${Tests})
-        # Strip newlines
-        string(REGEX REPLACE "\\\\\n|\n" "" TestName "${TestName}")
-
-        # Get test type and fixture if applicable
-        string(REGEX MATCH "(CATCH_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)[ \t]*\\([^,^\"]*" TestTypeAndFixture "${TestName}")
-        string(REGEX MATCH "(CATCH_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)" TestType "${TestTypeAndFixture}")
-        string(REPLACE "${TestType}(" "" TestFixture "${TestTypeAndFixture}")
-
-        # Get string parts of test definition
-        string(REGEX MATCHALL "\"+([^\\^\"]|\\\\\")+\"+" TestStrings "${TestName}")
-
-        # Strip wrapping quotation marks
-        string(REGEX REPLACE "^\"(.*)\"$" "\\1" TestStrings "${TestStrings}")
-        string(REPLACE "\";\"" ";" TestStrings "${TestStrings}")
-
-        # Validate that a test name and tags have been provided
-        list(LENGTH TestStrings TestStringsLength)
-        if(TestStringsLength GREATER 2 OR TestStringsLength LESS 1)
-            message(FATAL_ERROR "You must provide a valid test name and tags for all tests in ${SourceFile}")
-        endif()
-
-        # Assign name and tags
-        list(GET TestStrings 0 Name)
-        if("${TestType}" STREQUAL "SCENARIO")
-            set(Name "Scenario: ${Name}")
-        endif()
-        if(PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME AND TestFixture)
-            set(CTestName "${TestFixture}:${Name}")
-        else()
-            set(CTestName "${Name}")
-        endif()
-        if(PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME)
-            set(CTestName "${TestTarget}:${CTestName}")
-        endif()
-        # add target to labels to enable running all tests added from this target
-        set(Labels ${TestTarget})
-        if(TestStringsLength EQUAL 2)
-            list(GET TestStrings 1 Tags)
-            string(TOLOWER "${Tags}" Tags)
-            # remove target from labels if the test is hidden
-            if("${Tags}" MATCHES ".*\\[!?(hide|\\.)\\].*")
-                list(REMOVE_ITEM Labels ${TestTarget})
-            endif()
-            string(REPLACE "]" ";" Tags "${Tags}")
-            string(REPLACE "[" "" Tags "${Tags}")
-        endif()
-
-        list(APPEND Labels ${Tags})
-
-        list(FIND Labels "!hide" IndexOfHideLabel)
-        set(HiddenTagFound OFF)
-        foreach(label ${Labels})
-            string(REGEX MATCH "^!hide|^\\." result ${label})
-            if(result)
-                set(HiddenTagFound ON)
-                break()
-            endif(result)
-        endforeach(label)
-        if(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS AND ${HiddenTagFound})
-            PrintDebugMessage("Skipping test \"${CTestName}\" as it has [!hide], [.] or [.foo] label")
-        else()
-            PrintDebugMessage("Adding test \"${CTestName}\"")
-            if(Labels)
-                PrintDebugMessage("Setting labels to ${Labels}")
-            endif()
-
-            # Add the test and set its properties
-            add_test(NAME "\"${CTestName}\"" COMMAND ${TestTarget} ${Name} ${AdditionalCatchParameters})
-            set_tests_properties("\"${CTestName}\"" PROPERTIES FAIL_REGULAR_EXPRESSION "No tests ran"
-                                                    LABELS "${Labels}")
-        endif()
-
-    endforeach()
+  endforeach()
 endfunction()
 
 # entry point
 function(ParseAndAddCatchTests TestTarget)
-    PrintDebugMessage("Started parsing ${TestTarget}")
-    get_target_property(SourceFiles ${TestTarget} SOURCES)
-    PrintDebugMessage("Found the following sources: ${SourceFiles}")
-    foreach(SourceFile ${SourceFiles})
-        ParseFile(${SourceFile} ${TestTarget})
-    endforeach()
-    PrintDebugMessage("Finished parsing ${TestTarget}")
+  message(DEPRECATION "ParseAndAddCatchTest: function deprecated because of possibility of missed test cases. Consider using 'catch_discover_tests' from 'Catch.cmake'")
+  ParseAndAddCatchTests_PrintDebugMessage("Started parsing ${TestTarget}")
+  get_target_property(SourceFiles ${TestTarget} SOURCES)
+  ParseAndAddCatchTests_PrintDebugMessage("Found the following sources: ${SourceFiles}")
+  foreach(SourceFile ${SourceFiles})
+    ParseAndAddCatchTests_ParseFile(${SourceFile} ${TestTarget})
+  endforeach()
+  ParseAndAddCatchTests_PrintDebugMessage("Finished parsing ${TestTarget}")
 endfunction()

emscripten/CMakeLists.txt

@@ -17,9 +17,14 @@ add_definitions(-DCHAISCRIPT_NO_THREADS -DCHAISCRIPT_NO_DYNLOAD)
 add_executable(chaiscript chaiscript_em.cpp)
 target_include_directories(chaiscript PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/../include)
 
+# Enable WASM exception handling — ChaiScript relies on C++ exceptions for
+# error propagation; without this flag exceptions cause an abort in WASM.
+target_compile_options(chaiscript PRIVATE -fwasm-exceptions)
+
 # Emscripten link flags: enable embind, allow memory growth, export as ES module-compatible
 target_link_options(chaiscript PRIVATE
   --bind
+  -fwasm-exceptions
   -sALLOW_MEMORY_GROWTH=1
   -sEXPORT_ES6=0
   -sMODULARIZE=0

emscripten/chaiscript.html

@@ -185,6 +185,8 @@ print("10! = " + to_string(factorial(10)))
       outputEl.scrollTop = outputEl.scrollHeight;
     }
 
+    var chaiHandle = 0;
+
     var Module = {
       print: function(text) {
         appendOutput(text);
@@ -193,6 +195,7 @@ print("10! = " + to_string(factorial(10)))
         appendOutput(text, 'output-error');
       },
       onRuntimeInitialized: function() {
+        chaiHandle = Module.create();
         statusEl.textContent = 'Ready';
         statusEl.className = 'ready';
         btnRun.disabled = false;
@@ -205,7 +208,7 @@ print("10! = " + to_string(factorial(10)))
 
       appendOutput('> Running...', 'output-line');
       try {
-        Module.eval(code);
+        Module.eval(chaiHandle, code);
       } catch (e) {
         appendOutput('Error: ' + e.message, 'output-error');
       }

emscripten/chaiscript_em.cpp

@@ -13,11 +13,16 @@
 #include <emscripten/bind.h>
 
 EMSCRIPTEN_BINDINGS(chaiscript) {
+  emscripten::function("create", &chaiscript_create);
+  emscripten::function("destroy", &chaiscript_destroy);
   emscripten::function("eval", &chaiscript_eval);
   emscripten::function("evalString", &chaiscript_eval_string);
   emscripten::function("evalBool", &chaiscript_eval_bool);
   emscripten::function("evalInt", &chaiscript_eval_int);
   emscripten::function("evalFloat", &chaiscript_eval_float);
   emscripten::function("evalDouble", &chaiscript_eval_double);
+  emscripten::function("saveState", &chaiscript_save_state);
+  emscripten::function("restoreState", &chaiscript_restore_state);
+  emscripten::function("releaseState", &chaiscript_release_state);
 }
 #endif

emscripten/chaiscript_eval.hpp

@@ -7,42 +7,118 @@
 // Shared eval helper functions for the ChaiScript Emscripten wrapper.
 // These functions provide typed evaluation of ChaiScript expressions,
 // used by both the Emscripten/WebAssembly build and native tests.
+//
+// The interface is opaque and handle-based: JS callers create one or more
+// engines via chaiscript_create(), pass the resulting handle to the eval and
+// state helpers, and release the engine with chaiscript_destroy() when done.
+// State snapshots are themselves opaque handles produced by
+// chaiscript_save_state() and consumed by chaiscript_restore_state() /
+// chaiscript_release_state(). Hiding ChaiScript and ChaiScript::State behind
+// integer handles keeps embind from having to manage their lifetimes and
+// avoids forcing a static singleton on the C++ side.
 
 #ifndef CHAISCRIPT_EMSCRIPTEN_EVAL_HPP_
 #define CHAISCRIPT_EMSCRIPTEN_EVAL_HPP_
 
-#include <string>
 #include <chaiscript/chaiscript.hpp>
+#include <map>
+#include <memory>
+#include <string>
+#include <unordered_map>
 
 namespace detail {
-inline chaiscript::ChaiScript &get_chai_instance() {
-  static chaiscript::ChaiScript chai;
-  return chai;
-}
+  // ChaiScript::State captures globals/functions/types but not the top-level
+  // scripting locals (variables created by `var x = ...` at the script's
+  // outermost scope). The playground's reset-between-runs use case needs both,
+  // so the snapshot pairs the engine state with the locals map.
+  struct Snapshot {
+    chaiscript::ChaiScript::State engine_state;
+    std::map<std::string, chaiscript::Boxed_Value> locals;
+  };
+
+  inline std::unordered_map<int, std::unique_ptr<chaiscript::ChaiScript>> &chai_registry() {
+    static std::unordered_map<int, std::unique_ptr<chaiscript::ChaiScript>> registry;
+    return registry;
+  }
+
+  inline std::unordered_map<int, Snapshot> &state_registry() {
+    static std::unordered_map<int, Snapshot> registry;
+    return registry;
+  }
+
+  inline int next_handle() {
+    static int handle = 0;
+    return ++handle;
+  }
+
+  inline chaiscript::ChaiScript &get_chai(const int handle) {
+    return *chai_registry().at(handle);
+  }
 } // namespace detail
 
-inline void chaiscript_eval(const std::string &input) {
-  detail::get_chai_instance().eval(input);
+// Construct a fresh ChaiScript engine and return an opaque handle. The handle
+// is owned by the caller and must be released with chaiscript_destroy().
+inline int chaiscript_create() {
+  const int handle = detail::next_handle();
+  detail::chai_registry().emplace(handle, std::make_unique<chaiscript::ChaiScript>());
+  return handle;
 }
 
-inline std::string chaiscript_eval_string(const std::string &input) {
-  return detail::get_chai_instance().eval<std::string>(input);
+// Destroy an engine handle. Unknown handles are silently ignored so JS callers
+// do not need to track validity defensively.
+inline void chaiscript_destroy(const int handle) {
+  detail::chai_registry().erase(handle);
 }
 
-inline bool chaiscript_eval_bool(const std::string &input) {
-  return detail::get_chai_instance().eval<bool>(input);
+inline void chaiscript_eval(const int handle, const std::string &input) {
+  detail::get_chai(handle).eval(input);
 }
 
-inline int chaiscript_eval_int(const std::string &input) {
-  return detail::get_chai_instance().eval<int>(input);
+inline std::string chaiscript_eval_string(const int handle, const std::string &input) {
+  return detail::get_chai(handle).eval<std::string>(input);
 }
 
-inline float chaiscript_eval_float(const std::string &input) {
-  return detail::get_chai_instance().eval<float>(input);
+inline bool chaiscript_eval_bool(const int handle, const std::string &input) {
+  return detail::get_chai(handle).eval<bool>(input);
 }
 
-inline double chaiscript_eval_double(const std::string &input) {
-  return detail::get_chai_instance().eval<double>(input);
+inline int chaiscript_eval_int(const int handle, const std::string &input) {
+  return detail::get_chai(handle).eval<int>(input);
+}
+
+inline float chaiscript_eval_float(const int handle, const std::string &input) {
+  return detail::get_chai(handle).eval<float>(input);
+}
+
+inline double chaiscript_eval_double(const int handle, const std::string &input) {
+  return detail::get_chai(handle).eval<double>(input);
+}
+
+// Snapshot the engine identified by chai_handle and return a fresh opaque
+// state handle. Release it with chaiscript_release_state() when no longer
+// needed.
+inline int chaiscript_save_state(const int chai_handle) {
+  const int state_handle = detail::next_handle();
+  auto &chai = detail::get_chai(chai_handle);
+  detail::state_registry().emplace(state_handle, detail::Snapshot{chai.get_state(), chai.get_locals()});
+  return state_handle;
+}
+
+// Restore a previously snapshotted state onto the engine identified by
+// chai_handle. Unknown state handles are silently ignored.
+inline void chaiscript_restore_state(const int chai_handle, const int state_handle) {
+  const auto it = detail::state_registry().find(state_handle);
+  if (it != detail::state_registry().end()) {
+    auto &chai = detail::get_chai(chai_handle);
+    chai.set_state(it->second.engine_state);
+    chai.set_locals(it->second.locals);
+  }
+}
+
+// Release a state handle returned by chaiscript_save_state. Releasing an
+// unknown handle is a no-op.
+inline void chaiscript_release_state(const int state_handle) {
+  detail::state_registry().erase(state_handle);
 }
 
 #endif /* CHAISCRIPT_EMSCRIPTEN_EVAL_HPP_ */

grammar/chaiscript.ebnf

@@ -0,0 +1,189 @@
+/*
+ * ChaiScript Grammar — EBNF for Railroad Diagram Generation
+ *
+ * View as navigable railroad diagrams at:
+ *    https://www.bottlecaps.de/rr/ui  (IPv6)
+ *    https://rr.red-dove.com/ui       (IPv4)
+ *
+ * Copy and paste this file into the 'Edit Grammar' tab, then
+ * click 'View Diagram'.
+ *
+ * This grammar uses the notation accepted by
+ * https://github.com/GuntherRademacher/rr :
+ *   - "::=" as rule separator
+ *   - no semicolon at end of rule
+ *   - "?" "+" "*" for repetition
+ *   - C comments
+ */
+
+/* ---- Top-level ---- */
+
+statements           ::= ( def | try | if | while | class | enum
+                           | for | switch | return | break | continue
+                           | equation | block | eol )+
+
+/* ---- Functions ---- */
+
+def                  ::= "def" id ( "::" id )? "(" decl_arg_list ")" eol*
+                           ( ":" guard )? eol* block
+
+lambda               ::= "fun" ( "[" id_arg_list "]" )? "(" decl_arg_list ")" eol* block
+
+guard                ::= operator
+
+/* ---- Exception handling ---- */
+
+try                  ::= "try" eol* block catch* finally?
+catch                ::= "catch" ( "(" arg ")" )? eol* block
+finally              ::= "finally" eol* block
+
+/* ---- Control flow ---- */
+
+if                   ::= "if" "(" equation ( eol equation )? ")" eol* block
+                           ( "else" ( if | eol* block ) )*
+
+while                ::= "while" "(" operator ")" eol* block
+
+for                  ::= "for" "(" ( for_guards | equation ":" equation ) ")" eol* block
+for_guards           ::= equation eol equation eol equation
+
+switch               ::= "switch" "(" operator ")" eol* "{" ( case | default )+ "}"
+case                 ::= "case" "(" operator ")" eol* block
+default              ::= "default" eol* block
+
+/* ---- Classes ---- */
+
+class                ::= "class" id ( ":" id )? eol* class_block
+class_block          ::= "{" class_statements* "}"
+class_statements     ::= def | var_decl | eol
+
+/* ---- Enums ---- */
+
+enum                 ::= "enum" ( "class" | "struct" ) id ( ":" underlying_type )?
+                           "{" enum_entries? "}"
+
+enum_entries         ::= enum_entry ( "," enum_entry )*
+
+enum_entry           ::= id ( "=" integer )?
+
+underlying_type      ::= id
+
+
+/* ---- Blocks & flow keywords ---- */
+
+block                ::= "{" statements* "}"
+return               ::= "return" operator?
+break                ::= "break"
+continue             ::= "continue"
+
+/* ---- Line termination ---- */
+
+eol                  ::= "\n" | "\r\n" | ";"
+
+/* ---- Equations & operators ---- */
+
+equation             ::= operator ( ( "=" | ":=" | "+=" | "-=" | "*=" | "/="
+                           | "%=" | "<<=" | ">>=" | "&=" | "^=" | "|=" )
+                           equation )?
+
+operator             ::= prefix
+                       | value
+                       | operator binary_operator operator
+                       | operator "?" operator ":" operator
+
+prefix               ::= ( "++" | "--" | "-" | "+" | "!" | "~" ) operator
+
+binary_operator      ::= "||" | "&&"
+                       | "|" | "^" | "&"
+                       | "==" | "!="
+                       | "<" | "<=" | ">" | ">="
+                       | "<<" | ">>"
+                       | "+" | "-"
+                       | "*" | "/" | "%"
+
+/* ---- Values & access ---- */
+
+value                ::= var_decl | dot_fun_array | prefix
+
+dot_fun_array        ::= ( lambda | num | quoted_string
+                           | single_quoted_string | raw_string
+                           | paren_expression | inline_container
+                           | id )
+                           ( fun_call | array_call | dot_access )*
+
+fun_call             ::= "(" arg_list ")"
+array_call           ::= "[" operator "]"
+dot_access           ::= "." id
+
+/* ---- Variable declarations ---- */
+
+var_decl             ::= ( "auto" | "var" | "const" ) ( reference | id )
+                       | "global" ( reference | id )
+                       | "attr" id ( "::" id )?
+
+reference            ::= "&" id
+
+/* ---- Parenthesised & inline containers ---- */
+
+paren_expression     ::= "(" operator ")"
+
+inline_container     ::= "[" container_arg_list "]"
+container_arg_list   ::= value_range
+                       | map_pair ( "," map_pair )*
+                       | operator ( "," operator )*
+
+value_range          ::= operator ".." operator
+map_pair             ::= operator ":" operator
+
+/* ---- String literals ---- */
+
+quoted_string        ::= '"' ( char | escape | interpolation )* '"'
+single_quoted_string ::= "'" ( char | escape ) "'"
+raw_string           ::= 'R"' delimiter? "(" char* ")" delimiter? '"'
+delimiter            ::= [a-zA-Z0-9_]+
+interpolation        ::= "${" equation "}"
+
+/* ---- Escape sequences ---- */
+
+escape               ::= "\" ( "'" | '"' | "?" | "\" | "a" | "b"
+                           | "f" | "n" | "r" | "t" | "v" | "$"
+                           | "0"
+                           | "x" hex_digit+
+                           | "u" hex_digit hex_digit hex_digit hex_digit
+                           | "U" hex_digit hex_digit hex_digit hex_digit
+                               hex_digit hex_digit hex_digit hex_digit
+                           | octal_digit+ )
+
+/* ---- Argument lists ---- */
+
+id_arg_list          ::= id ( "," id )*
+decl_arg_list        ::= ( arg ( "," arg )* )?
+arg_list             ::= ( equation ( "," equation )* )?
+arg                  ::= id id?
+
+/* ---- Identifiers ---- */
+
+id                   ::= ( [a-zA-Z_] [a-zA-Z0-9_]* )
+                       | ( "`" [^`]+ "`" )
+                       | "true" | "false"
+                       | "Infinity" | "NaN"
+                       | "_"
+                       | "__LINE__" | "__FILE__" | "__FUNC__" | "__CLASS__"
+
+/* ---- Numeric literals ---- */
+
+num                  ::= hex | binary | float | integer
+
+hex                  ::= "0" ( "x" | "X" ) [0-9a-fA-F]+ int_suffix*
+binary               ::= "0" ( "b" | "B" ) [01]+ int_suffix*
+float                ::= [0-9]+ "." [0-9]+ ( ( "e" | "E" ) ( "+" | "-" )? [0-9]+ )? float_suffix?
+integer              ::= [0-9]+ int_suffix*
+
+int_suffix           ::= "l" | "L" | "ll" | "LL" | "u" | "U"
+float_suffix         ::= "l" | "L" | "f" | "F"
+
+/* ---- Character classes ---- */
+
+octal_digit          ::= [0-7]
+hex_digit            ::= [0-9a-fA-F]
+char                 ::= [^"\]

include/chaiscript/chaiscript.hpp

@@ -824,12 +824,14 @@ namespace chaiscript {
   public:
     ChaiScript(std::vector<std::string> t_modulepaths = {},
                std::vector<std::string> t_usepaths = {},
-               std::vector<Options> t_opts = chaiscript::default_options())
-        : ChaiScript_Basic(chaiscript::Std_Lib::library(),
+               std::vector<Options> t_opts = chaiscript::default_options(),
+               std::vector<Library_Options> t_lib_opts = {})
+        : ChaiScript_Basic(chaiscript::Std_Lib::library(t_lib_opts),
                            std::make_unique<parser::ChaiScript_Parser<eval::Noop_Tracer, optimizer::Optimizer_Default>>(),
                            std::move(t_modulepaths),
                            std::move(t_usepaths),
-                           std::move(t_opts)) {
+                           std::move(t_opts),
+                           std::find(t_lib_opts.begin(), t_lib_opts.end(), Library_Options::No_IO) != t_lib_opts.end()) {
     }
   };
 } // namespace chaiscript

include/chaiscript/chaiscript_defines.hpp

@@ -7,6 +7,16 @@
 #ifndef CHAISCRIPT_DEFINES_HPP_
 #define CHAISCRIPT_DEFINES_HPP_
 
+// MacOSX Fix: std::get/std::get_if/std::visit for std::variant are annotated
+// __attribute__((availability(macos,strict,introduced=10.14))) in Apple libc++.
+// Defining this macro before any libc++ header strips those annotations so
+// ChaiScript can be built against older MacOSX deployment targets.
+#if defined(__APPLE__) && defined(__clang__)
+#ifndef _LIBCPP_DISABLE_AVAILABILITY
+#define _LIBCPP_DISABLE_AVAILABILITY
+#endif
+#endif
+
 #ifdef _MSC_VER
 #define CHAISCRIPT_STRINGIZE(x) "" #x
 #define CHAISCRIPT_STRINGIZE_EXPANDED(x) CHAISCRIPT_STRINGIZE(x)
@@ -59,16 +69,30 @@ static_assert(_MSC_FULL_VER >= 190024210, "Visual C++ 2015 Update 3 or later req
 #define CHAISCRIPT_MODULE_EXPORT extern "C"
 #endif
 
-#if defined(CHAISCRIPT_MSVC) || (defined(__GNUC__) && __GNUC__ >= 5) || defined(CHAISCRIPT_CLANG)
-#define CHAISCRIPT_UTF16_UTF32
-#endif
-
 #ifdef _DEBUG
 #define CHAISCRIPT_DEBUG true
 #else
 #define CHAISCRIPT_DEBUG false
 #endif
 
+// Upper bound on the depth of nested ChaiScript function calls. Hitting it
+// causes the dispatcher to throw chaiscript::exception::stack_overflow_error
+// instead of letting the native call stack overflow. Defining the macro on
+// the command line overrides the default.
+//
+// MSVC Debug builds emit very large per-frame native stack usage (no inlining,
+// /RTC, buffer security checks) and Windows defaults to a 1 MiB thread stack,
+// so the same ChaiScript depth that fits comfortably on Linux/macOS or in an
+// MSVC Release build overflows the native stack before the depth check fires.
+// We pick a tighter default in that configuration to keep the throw reachable.
+#ifndef CHAISCRIPT_MAX_CALL_DEPTH
+#if defined(CHAISCRIPT_MSVC) && CHAISCRIPT_DEBUG
+#define CHAISCRIPT_MAX_CALL_DEPTH 32
+#else
+#define CHAISCRIPT_MAX_CALL_DEPTH 256
+#endif
+#endif
+
 #include <cmath>
 #include <memory>
 #include <string>
@@ -82,6 +106,9 @@ namespace chaiscript {
   constexpr static const char *compiler_name = CHAISCRIPT_COMPILER_NAME;
   constexpr static const bool debug_build = CHAISCRIPT_DEBUG;
 
+  constexpr static const int max_call_depth = CHAISCRIPT_MAX_CALL_DEPTH;
+  static_assert(max_call_depth > 0, "CHAISCRIPT_MAX_CALL_DEPTH must be a positive integer");
+
   template<typename B, typename D, typename... Arg>
   inline std::shared_ptr<B> make_shared(Arg &&...arg) {
 #ifdef CHAISCRIPT_USE_STD_MAKE_SHARED
@@ -211,6 +238,13 @@ namespace chaiscript {
     External_Scripts
   };
 
+  enum class Library_Options {
+    No_Stdlib,
+    No_IO,
+    No_Prelude,
+    No_JSON
+  };
+
   template<typename From, typename To>
   struct is_nothrow_forward_constructible : std::bool_constant<noexcept(To{std::declval<From>()})> {
   };

include/chaiscript/chaiscript_stdlib.hpp

@@ -10,6 +10,7 @@
 #include <map>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <utility>
 #include <vector>
 
@@ -18,11 +19,11 @@
 
 #include "dispatchkit/function_call.hpp"
 
-//#include "dispatchkit/dispatchkit.hpp"
+// #include "dispatchkit/dispatchkit.hpp"
 #include "dispatchkit/bootstrap.hpp"
 #include "dispatchkit/bootstrap_stl.hpp"
 #include "dispatchkit/operators.hpp"
-//#include "dispatchkit/boxed_value.hpp"
+// #include "dispatchkit/boxed_value.hpp"
 #include "dispatchkit/register_function.hpp"
 #include "language/chaiscript_prelude.hpp"
 #include "utility/json_wrap.hpp"
@@ -38,25 +39,41 @@
 namespace chaiscript {
   class Std_Lib {
   public:
-    [[nodiscard]] static ModulePtr library() {
+    [[nodiscard]] static ModulePtr library(const std::vector<Library_Options> &t_opts = {}) {
+      if (std::find(t_opts.begin(), t_opts.end(), Library_Options::No_Stdlib) != t_opts.end()) {
+        return std::make_shared<Module>();
+      }
+
       auto lib = std::make_shared<Module>();
+
+      const bool no_prelude = std::find(t_opts.begin(), t_opts.end(), Library_Options::No_Prelude) != t_opts.end();
+      const bool no_json = std::find(t_opts.begin(), t_opts.end(), Library_Options::No_JSON) != t_opts.end();
+
       bootstrap::Bootstrap::bootstrap(*lib);
 
       bootstrap::standard_library::vector_type<std::vector<Boxed_Value>>("Vector", *lib);
       bootstrap::standard_library::string_type<std::string>("string", *lib);
+      bootstrap::standard_library::string_view_type<std::string_view, std::string>("string_view", *lib);
       bootstrap::standard_library::map_type<std::map<std::string, Boxed_Value>>("Map", *lib);
       bootstrap::standard_library::pair_type<std::pair<Boxed_Value, Boxed_Value>>("Pair", *lib);
 
+      // Allow explicit conversion from std::string_view back to std::string,
+      // e.g. `string(sv)` in ChaiScript.
+      lib->add(fun([](const std::string_view sv) { return std::string{sv}; }), "string");
+
 #ifndef CHAISCRIPT_NO_THREADS
       bootstrap::standard_library::future_type<std::future<chaiscript::Boxed_Value>>("future", *lib);
-      lib->add(chaiscript::fun(
-                   [](const std::function<chaiscript::Boxed_Value()> &t_func) { return std::async(std::launch::async, t_func); }),
-               "async");
+      // Note: async() is registered in ChaiScript_Basic::build_eval_system()
+      // with thread tracking to prevent heap-use-after-free on engine destruction.
 #endif
 
-      json_wrap::library(*lib);
+      if (!no_json) {
+        json_wrap::library(*lib);
+      }
 
-      lib->eval(ChaiScript_Prelude::chaiscript_prelude() /*, "standard prelude"*/);
+      if (!no_prelude) {
+        lib->eval(ChaiScript_Prelude::chaiscript_prelude() /*, "standard prelude"*/);
+      }
 
       return lib;
     }

include/chaiscript/dispatchkit/bootstrap.hpp

@@ -26,7 +26,7 @@ namespace chaiscript::bootstrap {
               throw std::range_error("Array index out of range. Received: " + std::to_string(index) + " expected < "
                                      + std::to_string(extent));
             } else {
-              return t[index];
+              return *std::next(t, static_cast<std::ptrdiff_t>(index));
             }
           }),
           "[]");
@@ -37,7 +37,7 @@ namespace chaiscript::bootstrap {
               throw std::range_error("Array index out of range. Received: " + std::to_string(index) + " expected < "
                                      + std::to_string(extent));
             } else {
-              return t[index];
+              return *std::next(t, static_cast<std::ptrdiff_t>(index));
             }
           }),
           "[]");
@@ -115,6 +115,8 @@ namespace chaiscript::bootstrap {
 
     m.add(fun(&parse_string<T>), "to_" + name);
     m.add(fun([](const T t) { return t; }), "to_" + name);
+    m.add(fun([](const Boxed_Number &bn) { return bn.get_as<T>(); }), "to_" + name);
+    m.add(fun(&parse_string<T>), name);
   }
 
   /// "clone" function for a shared_ptr type. This is used in the case
@@ -266,7 +268,7 @@ namespace chaiscript::bootstrap {
   public:
     /// \brief perform all common bootstrap functions for std::string, void and POD types
     /// \param[in,out] m Module to add bootstrapped functions to
-    /// \returns passed in Module
+    /// \param[in] t_no_io If true, skip registering print_string and println_string
     static void bootstrap(Module &m) {
       m.add(user_type<void>(), "void");
       m.add(user_type<bool>(), "bool");
@@ -435,9 +437,6 @@ namespace chaiscript::bootstrap {
       m.add(fun(&Build_Info::compiler_id), "compiler_id");
       m.add(fun(&Build_Info::debug_build), "debug_build");
 
-      m.add(fun(&print), "print_string");
-      m.add(fun(&println), "println_string");
-
       m.add(dispatch::make_dynamic_proxy_function(&bind_function), "bind");
 
       m.add(fun(&shared_ptr_unconst_clone<dispatch::Proxy_Function_Base>), "clone");

include/chaiscript/dispatchkit/bootstrap_stl.hpp

@@ -18,6 +18,7 @@
 #include <functional>
 #include <memory>
 #include <stdexcept>
+#include <type_traits>
 #include <typeinfo>
 #include <vector>
 
@@ -84,6 +85,15 @@ namespace chaiscript::bootstrap::standard_library {
       return t_target.count(t_key);
     }
 
+    template<typename T>
+    Boxed_Value find(const T &t_target, const typename T::key_type &t_key) {
+      const auto itr = t_target.find(t_key);
+      if (itr != t_target.end()) {
+        return Boxed_Value(itr->second);
+      }
+      return Boxed_Value();
+    }
+
     template<typename T>
     void insert(T &t_target, const T &t_other) {
       t_target.insert(t_other.begin(), t_other.end());
@@ -170,18 +180,22 @@ namespace chaiscript::bootstrap::standard_library {
   /// http://www.sgi.com/tech/stl/Assignable.html
   template<typename ContainerType>
   void assignable_type(const std::string &type, Module &m) {
-    copy_constructor<ContainerType>(type, m);
-    operators::assign<ContainerType>(m);
+    if constexpr (std::is_copy_constructible_v<typename ContainerType::value_type>) {
+      copy_constructor<ContainerType>(type, m);
+      operators::assign<ContainerType>(m);
+    }
   }
 
   /// Add container resize concept to the given ContainerType
   /// http://www.cplusplus.com/reference/stl/
   template<typename ContainerType>
   void resizable_type(const std::string & /*type*/, Module &m) {
-    m.add(fun([](ContainerType *a, typename ContainerType::size_type n, const typename ContainerType::value_type &val) {
-            return a->resize(n, val);
-          }),
-          "resize");
+    if constexpr (std::is_copy_constructible_v<typename ContainerType::value_type>) {
+      m.add(fun([](ContainerType *a, typename ContainerType::size_type n, const typename ContainerType::value_type &val) {
+              return a->resize(n, val);
+            }),
+            "resize");
+    }
     m.add(fun([](ContainerType *a, typename ContainerType::size_type n) { return a->resize(n); }), "resize");
   }
 
@@ -213,13 +227,15 @@ namespace chaiscript::bootstrap::standard_library {
   /// http://www.sgi.com/tech/stl/Sequence.html
   template<typename ContainerType>
   void sequence_type(const std::string & /*type*/, Module &m) {
-    m.add(fun(&detail::insert_at<ContainerType>), []() -> std::string {
-      if (typeid(typename ContainerType::value_type) == typeid(Boxed_Value)) {
-        return "insert_ref_at";
-      } else {
-        return "insert_at";
-      }
-    }());
+    if constexpr (std::is_copy_constructible_v<typename ContainerType::value_type>) {
+      m.add(fun(&detail::insert_at<ContainerType>), []() -> std::string {
+        if (typeid(typename ContainerType::value_type) == typeid(Boxed_Value)) {
+          return "insert_ref_at";
+        } else {
+          return "insert_at";
+        }
+      }());
+    }
 
     m.add(fun(&detail::erase_at<ContainerType>), "erase_at");
   }
@@ -245,27 +261,29 @@ namespace chaiscript::bootstrap::standard_library {
           }),
           "back");
 
-    using push_back = void (ContainerType::*)(const typename ContainerType::value_type &);
-    m.add(fun(static_cast<push_back>(&ContainerType::push_back)), [&]() -> std::string {
-      if (typeid(typename ContainerType::value_type) == typeid(Boxed_Value)) {
-        m.eval("# Pushes the second value onto the container while making a clone of the value\n"
-               "def push_back("
-               + type
-               + " container, x)\n"
-                 "{ \n"
-                 "  if (x.is_var_return_value()) {\n"
-                 "    x.reset_var_return_value() \n"
-                 "    container.push_back_ref(x) \n"
-                 "  } else { \n"
-                 "    container.push_back_ref(clone(x)); \n"
-                 "  }\n"
-                 "} \n");
+    if constexpr (std::is_copy_constructible_v<typename ContainerType::value_type>) {
+      using push_back = void (ContainerType::*)(const typename ContainerType::value_type &);
+      m.add(fun(static_cast<push_back>(&ContainerType::push_back)), [&]() -> std::string {
+        if (typeid(typename ContainerType::value_type) == typeid(Boxed_Value)) {
+          m.eval("# Pushes the second value onto the container while making a clone of the value\n"
+                 "def push_back("
+                 + type
+                 + " container, x)\n"
+                   "{ \n"
+                   "  if (x.is_var_return_value()) {\n"
+                   "    x.reset_var_return_value() \n"
+                   "    container.push_back_ref(x) \n"
+                   "  } else { \n"
+                   "    container.push_back_ref(clone(x)); \n"
+                   "  }\n"
+                   "} \n");
 
-        return "push_back_ref";
-      } else {
-        return "push_back";
-      }
-    }());
+          return "push_back_ref";
+        } else {
+          return "push_back";
+        }
+      }());
+    }
 
     m.add(fun(&ContainerType::pop_back), "pop_back");
   }
@@ -295,25 +313,27 @@ namespace chaiscript::bootstrap::standard_library {
           }),
           "front");
 
-    m.add(fun(static_cast<push_ptr>(&ContainerType::push_front)), [&]() -> std::string {
-      if (typeid(typename ContainerType::value_type) == typeid(Boxed_Value)) {
-        m.eval("# Pushes the second value onto the front of container while making a clone of the value\n"
-               "def push_front("
-               + type
-               + " container, x)\n"
-                 "{ \n"
-                 "  if (x.is_var_return_value()) {\n"
-                 "    x.reset_var_return_value() \n"
-                 "    container.push_front_ref(x) \n"
-                 "  } else { \n"
-                 "    container.push_front_ref(clone(x)); \n"
-                 "  }\n"
-                 "} \n");
-        return "push_front_ref";
-      } else {
-        return "push_front";
-      }
-    }());
+    if constexpr (std::is_copy_constructible_v<typename ContainerType::value_type>) {
+      m.add(fun(static_cast<push_ptr>(&ContainerType::push_front)), [&]() -> std::string {
+        if (typeid(typename ContainerType::value_type) == typeid(Boxed_Value)) {
+          m.eval("# Pushes the second value onto the front of container while making a clone of the value\n"
+                 "def push_front("
+                 + type
+                 + " container, x)\n"
+                   "{ \n"
+                   "  if (x.is_var_return_value()) {\n"
+                   "    x.reset_var_return_value() \n"
+                   "    container.push_front_ref(x) \n"
+                   "  } else { \n"
+                   "    container.push_front_ref(clone(x)); \n"
+                   "  }\n"
+                   "} \n");
+          return "push_front_ref";
+        } else {
+          return "push_front";
+        }
+      }());
+    }
 
     m.add(fun(static_cast<pop_ptr>(&ContainerType::pop_front)), "pop_front");
   }
@@ -344,6 +364,7 @@ namespace chaiscript::bootstrap::standard_library {
   template<typename ContainerType>
   void unique_associative_container_type(const std::string & /*type*/, Module &m) {
     m.add(fun(detail::count<ContainerType>), "count");
+    m.add(fun(detail::find<ContainerType>), "find");
 
     using erase_ptr = size_t (ContainerType::*)(const typename ContainerType::key_type &);
 
@@ -518,6 +539,61 @@ namespace chaiscript::bootstrap::standard_library {
     m.add(fun([](const String *s, size_t pos, size_t len) { return s->substr(pos, len); }), "substr");
   }
 
+  /// Add a String_View type (e.g. std::string_view), with conversions to and from
+  /// the matching owning String type (e.g. std::string).
+  ///
+  /// Mirrors the search/substring surface of string_type so that scripts can
+  /// traverse a buffer through StringView without allocating. Sharing method
+  /// names with the owning String type is safe: dispatch deprioritizes any
+  /// candidate whose first/receiver argument requires a type conversion (see
+  /// dispatch() in proxy_functions.hpp), so myString.substr(1, 2) still
+  /// resolves to String::substr while mySV.substr(1, 2) resolves to
+  /// StringView::substr (returning a StringView).
+  ///
+  /// \note A String_View is a non-owning reference. Constructing one from a
+  /// temporary owning String yields a dangling reference once that temporary
+  /// is destroyed; the same lifetime caveats as in C++ apply here.
+  template<typename StringView, typename String>
+  void string_view_type(const std::string &type, Module &m) {
+    m.add(user_type<StringView>(), type);
+    m.add(constructor<StringView()>(), type);
+    m.add(constructor<StringView(const StringView &)>(), type);
+    m.add(fun([](const String &s) { return StringView{s}; }), type);
+
+    opers_comparison<StringView>(m);
+
+    m.add(fun([](const StringView *s) { return s->size(); }), "size");
+    m.add(fun([](const StringView *s) { return s->length(); }), "length");
+    m.add(fun([](const StringView *s) { return s->empty(); }), "empty");
+    m.add(fun([](const StringView *s) { return s->data(); }), "data");
+
+    // Random-access via [] / at, returning const_reference; StringView is read-only.
+    m.add(fun([](const StringView &sv, int index) -> typename StringView::const_reference {
+            return sv.at(static_cast<typename StringView::size_type>(index));
+          }),
+          "[]");
+
+    m.add(fun([](const StringView *s, const StringView &f, size_t pos) { return s->find(f, pos); }), "find");
+    m.add(fun([](const StringView *s, const StringView &f, size_t pos) { return s->rfind(f, pos); }), "rfind");
+    m.add(fun([](const StringView *s, const StringView &f, size_t pos) { return s->find_first_of(f, pos); }), "find_first_of");
+    m.add(fun([](const StringView *s, const StringView &f, size_t pos) { return s->find_last_of(f, pos); }), "find_last_of");
+    m.add(fun([](const StringView *s, const StringView &f, size_t pos) { return s->find_last_not_of(f, pos); }), "find_last_not_of");
+    m.add(fun([](const StringView *s, const StringView &f, size_t pos) { return s->find_first_not_of(f, pos); }), "find_first_not_of");
+
+    m.add(fun([](const StringView *s, const StringView &f) { return s->starts_with(f); }), "starts_with");
+    m.add(fun([](const StringView *s, const StringView &f) { return s->ends_with(f); }), "ends_with");
+
+    m.add(fun([](const StringView *s, size_t pos, size_t len) { return s->substr(pos, len); }), "substr");
+
+    // Built-in implicit conversion from owning String to non-owning StringView.
+    m.add(type_conversion<const String &, StringView>());
+
+    // Explicit conversion from StringView back to owning String, registered as
+    // to_string(sv); the call site can also register it under the owning type's
+    // name (e.g. string(sv)) when desired.
+    m.add(fun([](const StringView sv) { return String{sv}; }), "to_string");
+  }
+
   /// Add a MapType container
   /// http://www.sgi.com/tech/stl/Map.html
   template<typename FutureType>

include/chaiscript/dispatchkit/boxed_number.hpp

@@ -41,7 +41,7 @@ namespace chaiscript {
 // this is OK, so we're disabling size/and sign type warnings
 #ifdef CHAISCRIPT_MSVC
 #pragma warning(push)
-#pragma warning(disable : 4244 4018 4389 4146 4365 4267 4242)
+#pragma warning(disable : 4244 4018 4389 4146 4365 4267 4242 4702) // 4702 is for broken unreachable warning
 #endif
 
 #ifdef __GNUC__
@@ -220,7 +220,6 @@ namespace chaiscript {
         if constexpr (!std::is_floating_point<LHS>::value && !std::is_floating_point<RHS>::value) {
           switch (t_oper) {
             case Operators::Opers::assign_bitwise_and:
-              check_divide_by_zero(c_rhs);
               *t_lhs &= c_rhs;
               return t_bv;
             case Operators::Opers::assign_bitwise_or:
@@ -233,6 +232,7 @@ namespace chaiscript {
               *t_lhs >>= c_rhs;
               return t_bv;
             case Operators::Opers::assign_remainder:
+              check_divide_by_zero(c_rhs);
               *t_lhs %= c_rhs;
               return t_bv;
             case Operators::Opers::assign_bitwise_xor:

include/chaiscript/dispatchkit/dispatchkit.hpp

@@ -19,6 +19,7 @@
 #include <stdexcept>
 #include <string>
 #include <string_view>
+#include <thread>
 #include <typeinfo>
 #include <utility>
 #include <vector>
@@ -33,7 +34,6 @@
 #include "dynamic_object.hpp"
 #include "proxy_constructors.hpp"
 #include "proxy_functions.hpp"
-#include "short_alloc.hpp"
 #include "type_conversions.hpp"
 #include "type_info.hpp"
 
@@ -121,6 +121,19 @@ namespace chaiscript {
       global_non_const(const global_non_const &) = default;
       ~global_non_const() noexcept override = default;
     };
+
+    /// Exception thrown when the ChaiScript call stack exceeds
+    /// chaiscript::max_call_depth, signalling runaway recursion before the
+    /// native stack can overflow.
+    class stack_overflow_error : public std::runtime_error {
+    public:
+      stack_overflow_error() noexcept
+          : std::runtime_error("Maximum call stack depth exceeded") {
+      }
+
+      stack_overflow_error(const stack_overflow_error &) = default;
+      ~stack_overflow_error() noexcept override = default;
+    };
   } // namespace exception
 
   /// \brief Holds a collection of ChaiScript settings which can be applied to the ChaiScript runtime.
@@ -317,9 +330,6 @@ namespace chaiscript {
 
   namespace detail {
     struct Stack_Holder {
-      // template <class T, std::size_t BufSize = sizeof(T)*20000>
-      //  using SmallVector = std::vector<T, short_alloc<T, BufSize>>;
-
       template<class T>
       using SmallVector = std::vector<T>;
 
@@ -370,6 +380,28 @@ namespace chaiscript {
           , m_parser(parser) {
       }
 
+      ~Dispatch_Engine() {
+        join_async_threads();
+      }
+
+      Dispatch_Engine(const Dispatch_Engine &) = delete;
+      Dispatch_Engine &operator=(const Dispatch_Engine &) = delete;
+      Dispatch_Engine(Dispatch_Engine &&) = delete;
+      Dispatch_Engine &operator=(Dispatch_Engine &&) = delete;
+
+#ifndef CHAISCRIPT_NO_THREADS
+      /// Track an async thread so it can be joined during destruction
+      void track_async_thread(std::thread t_thread) {
+        chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::shared_mutex> l(m_async_mutex);
+        // Clean up already-finished threads to avoid unbounded growth
+        m_async_threads.erase(
+            std::remove_if(m_async_threads.begin(), m_async_threads.end(),
+                           [](std::thread &t) { return !t.joinable(); }),
+            m_async_threads.end());
+        m_async_threads.push_back(std::move(t_thread));
+      }
+#endif
+
       /// \brief casts an object while applying any Dynamic_Conversion available
       template<typename Type>
       decltype(auto) boxed_cast(const Boxed_Value &bv) const {
@@ -767,13 +799,13 @@ namespace chaiscript {
           t_loc = uint_fast32_t(funs.first);
         }
 
-        const auto do_attribute_call = [this](int l_num_params,
+        const auto do_attribute_call = [this](std::size_t l_num_params,
                                               Function_Params l_params,
                                               const std::vector<Proxy_Function> &l_funs,
                                               const Type_Conversions_State &l_conversions) -> Boxed_Value {
-          Function_Params attr_params(l_params.begin(), l_params.begin() + l_num_params);
+          Function_Params attr_params(l_params.first(l_num_params));
           Boxed_Value bv = dispatch::dispatch(l_funs, attr_params, l_conversions);
-          if (l_num_params < int(l_params.size()) || bv.get_type_info().bare_equal(user_type<dispatch::Proxy_Function_Base>())) {
+          if (l_num_params < l_params.size() || bv.get_type_info().bare_equal(user_type<dispatch::Proxy_Function_Base>())) {
             struct This_Foist {
               This_Foist(Dispatch_Engine &e, const Boxed_Value &t_bv)
                   : m_e(e) {
@@ -791,16 +823,16 @@ namespace chaiscript {
             try {
               auto func = boxed_cast<const dispatch::Proxy_Function_Base *>(bv);
               try {
-                return (*func)({l_params.begin() + l_num_params, l_params.end()}, l_conversions);
+                return (*func)(l_params.subspan(l_num_params), l_conversions);
               } catch (const chaiscript::exception::bad_boxed_cast &) {
               } catch (const chaiscript::exception::arity_error &) {
               } catch (const chaiscript::exception::guard_error &) {
               }
-              throw chaiscript::exception::dispatch_error({l_params.begin() + l_num_params, l_params.end()},
+              throw chaiscript::exception::dispatch_error(l_params.subspan(l_num_params),
                                                           std::vector<Const_Proxy_Function>{boxed_cast<Const_Proxy_Function>(bv)});
             } catch (const chaiscript::exception::bad_boxed_cast &) {
               // unable to convert bv into a Proxy_Function_Base
-              throw chaiscript::exception::dispatch_error({l_params.begin() + l_num_params, l_params.end()},
+              throw chaiscript::exception::dispatch_error(l_params.subspan(l_num_params),
                                                           std::vector<Const_Proxy_Function>(l_funs.begin(), l_funs.end()));
             }
           } else {
@@ -850,7 +882,7 @@ namespace chaiscript {
           if (!functions.empty()) {
             try {
               if (is_no_param) {
-                auto tmp_params = params.to_vector();
+                auto tmp_params = std::vector<Boxed_Value>(params.begin(), params.end());
                 tmp_params.insert(tmp_params.begin() + 1, var(t_name));
                 return do_attribute_call(2, Function_Params(tmp_params), functions, t_conversions);
               } else {
@@ -925,7 +957,7 @@ namespace chaiscript {
         const auto &f = this->boxed_cast<Const_Proxy_Function>(params[0]);
         const Type_Conversions_State convs(m_conversions, m_conversions.conversion_saves());
 
-        return const_var(f->call_match(Function_Params(params.begin() + 1, params.end()), convs));
+        return const_var(f->call_match(Function_Params(params.subspan(1)), convs));
       }
 
       /// Dump all system info to stdout
@@ -991,6 +1023,10 @@ namespace chaiscript {
       void save_function_params(const Function_Params &t_params) { save_function_params(*m_stack_holder, t_params); }
 
       void new_function_call(Stack_Holder &t_s, Type_Conversions::Conversion_Saves &t_saves) {
+        if (t_s.call_depth >= max_call_depth) {
+          throw chaiscript::exception::stack_overflow_error{};
+        }
+
         if (t_s.call_depth == 0) {
           m_conversions.enable_conversion_saves(t_saves, true);
         }
@@ -1064,13 +1100,21 @@ namespace chaiscript {
         // overridden methods in derived classes are tried first during dispatch
         const auto &lhs_dotn = lhs->dynamic_object_type_name();
         const auto &rhs_dotn = rhs->dynamic_object_type_name();
-        if (!lhs_dotn.empty() && !rhs_dotn.empty() && lhs_dotn != rhs_dotn) {
-          if (dispatch::Dynamic_Object::type_matches(lhs_dotn, rhs_dotn)) {
-            return true; // lhs is derived from rhs, so lhs is more specific
+        if (lhs_dotn != rhs_dotn) {
+          if (!lhs_dotn.empty() && !rhs_dotn.empty()) {
+            if (dispatch::Dynamic_Object::type_matches(lhs_dotn, rhs_dotn)) {
+              return true; // lhs is derived from rhs, so lhs is more specific
+            }
+            if (dispatch::Dynamic_Object::type_matches(rhs_dotn, lhs_dotn)) {
+              return false; // rhs is derived from lhs, so rhs is more specific
+            }
           }
-          if (dispatch::Dynamic_Object::type_matches(rhs_dotn, lhs_dotn)) {
-            return false; // rhs is derived from lhs, so rhs is more specific
+          // Impose a total order on type names to maintain strict-weak ordering:
+          // non-empty names sort before empty names, then lexicographically
+          if (lhs_dotn.empty() != rhs_dotn.empty()) {
+            return !lhs_dotn.empty();
           }
+          return lhs_dotn < rhs_dotn;
         }
 
         const auto &lhsparamtypes = lhs->get_param_types();
@@ -1120,7 +1164,9 @@ namespace chaiscript {
           return lt < rt;
         }
 
-        return false;
+        // When all overlapping parameters match, order by arity to maintain
+        // strict-weak ordering (transitivity of equivalence)
+        return lhssize < rhssize;
       }
 
       /// Implementation detail for adding a function.
@@ -1165,6 +1211,21 @@ namespace chaiscript {
         get_function_objects_int().insert_or_assign(t_name, std::move(new_func));
       }
 
+      void join_async_threads() {
+#ifndef CHAISCRIPT_NO_THREADS
+        std::vector<std::thread> threads;
+        {
+          chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::shared_mutex> l(m_async_mutex);
+          threads = std::move(m_async_threads);
+        }
+        for (auto &t : threads) {
+          if (t.joinable()) {
+            t.join();
+          }
+        }
+#endif
+      }
+
       mutable chaiscript::detail::threading::shared_mutex m_mutex;
 
       Type_Conversions m_conversions;
@@ -1174,6 +1235,11 @@ namespace chaiscript {
       mutable std::atomic_uint_fast32_t m_method_missing_loc = {0};
 
       State m_state;
+
+#ifndef CHAISCRIPT_NO_THREADS
+      mutable chaiscript::detail::threading::shared_mutex m_async_mutex;
+      std::vector<std::thread> m_async_threads;
+#endif
     };
 
     class Dispatch_State {

include/chaiscript/dispatchkit/dynamic_object.hpp

@@ -65,7 +65,6 @@ namespace chaiscript {
         return false;
       }
 
-
       bool is_explicit() const noexcept { return m_option_explicit; }
 
       void set_explicit(const bool t_explicit) noexcept { m_option_explicit = t_explicit; }

include/chaiscript/dispatchkit/dynamic_object_detail.hpp

@@ -103,7 +103,9 @@ namespace chaiscript {
 
           assert(types.size() > 1);
           // assert(types[1].bare_equal(user_type<Boxed_Value>()));
-          types[1] = t_objectti;
+          // When the object type_info is undefined (ChaiScript-defined class), use
+          // Dynamic_Object so that dispatch priority scoring works correctly.
+          types[1] = t_objectti.is_undef() ? user_type<Dynamic_Object>() : t_objectti;
           return types;
         }
 
@@ -146,11 +148,11 @@ namespace chaiscript {
       };
 
       /**
- * A Proxy_Function implementation designed for creating a new
- * Dynamic_Object
- * that is automatically guarded based on the first param based on the
- * param's type name
- */
+       * A Proxy_Function implementation designed for creating a new
+       * Dynamic_Object
+       * that is automatically guarded based on the first param based on the
+       * param's type name
+       */
       class Dynamic_Object_Constructor final : public Proxy_Function_Base {
       public:
         Dynamic_Object_Constructor(std::string t_type_name, const Proxy_Function &t_func)

include/chaiscript/dispatchkit/function_call_detail.hpp

@@ -55,10 +55,23 @@ namespace chaiscript::dispatch::detail {
       }
     }
 
+    template<typename T>
+    struct is_shared_ptr : std::false_type {};
+
+    template<typename T>
+    struct is_shared_ptr<std::shared_ptr<T>> : std::true_type {};
+
     template<typename P, typename Q>
     static Boxed_Value box(Q &&q) {
+      using bare_p = std::remove_cv_t<std::remove_reference_t<P>>;
       if constexpr (std::is_same_v<chaiscript::Boxed_Value, std::decay_t<Q>>) {
         return std::forward<Q>(q);
+      } else if constexpr (is_shared_ptr<bare_p>::value) {
+        // Pass shared_ptr arguments through by value rather than wrapping a
+        // reference. Boxed_Value's shared_ptr-aware overloads then record the
+        // bare type as the pointee, allowing dispatch to a C++ function that
+        // takes the same shared_ptr<T> on the other side.
+        return Boxed_Value(bare_p(std::forward<Q>(q)));
       } else if constexpr (std::is_reference_v<P>) {
         return Boxed_Value(std::ref(std::forward<Q>(q)));
       } else {

include/chaiscript/dispatchkit/function_params.hpp

@@ -12,55 +12,11 @@
 
 #include "boxed_value.hpp"
 
+#include <span>
+
 namespace chaiscript {
-  class Function_Params {
-  public:
-    constexpr Function_Params(const Boxed_Value *const t_begin, const Boxed_Value *const t_end)
-        : m_begin(t_begin)
-        , m_end(t_end) {
-    }
 
-    explicit Function_Params(const Boxed_Value &bv)
-        : m_begin(&bv)
-        , m_end(m_begin + 1) {
-    }
-
-    explicit Function_Params(const std::vector<Boxed_Value> &vec)
-        : m_begin(vec.empty() ? nullptr : &vec.front())
-        , m_end(vec.empty() ? nullptr : &vec.front() + vec.size()) {
-    }
-
-    template<size_t Size>
-    constexpr explicit Function_Params(const std::array<Boxed_Value, Size> &a)
-        : m_begin(&a.front())
-        , m_end(&a.front() + Size) {
-    }
-
-    [[nodiscard]] constexpr const Boxed_Value &operator[](const std::size_t t_i) const noexcept { return m_begin[t_i]; }
-
-    [[nodiscard]] constexpr const Boxed_Value *begin() const noexcept { return m_begin; }
-
-    [[nodiscard]] constexpr const Boxed_Value &front() const noexcept { return *m_begin; }
-
-    [[nodiscard]] constexpr const Boxed_Value *end() const noexcept { return m_end; }
-
-    [[nodiscard]] constexpr std::size_t size() const noexcept { return std::size_t(m_end - m_begin); }
-
-    [[nodiscard]] std::vector<Boxed_Value> to_vector() const { return std::vector<Boxed_Value>{m_begin, m_end}; }
-
-    [[nodiscard]] constexpr bool empty() const noexcept { return m_begin == m_end; }
-
-  private:
-    const Boxed_Value *m_begin = nullptr;
-    const Boxed_Value *m_end = nullptr;
-  };
-
-  // Constructor specialization for array of size 0
-  template<>
-  constexpr Function_Params::Function_Params(const std::array<Boxed_Value, size_t{0}> & /* a */)
-      : m_begin(nullptr)
-      , m_end(nullptr) {
-  }
+  using Function_Params = std::span<const Boxed_Value>;
 
 } // namespace chaiscript
 

include/chaiscript/dispatchkit/function_signature.hpp

@@ -64,7 +64,7 @@ namespace chaiscript::dispatch::detail {
   Function_Signature(Ret (Class::*f)(Param...) volatile &) -> Function_Signature<Ret, Function_Params<volatile Class &, Param...>, false, true>;
 
   template<typename Ret, typename Class, typename... Param>
-  Function_Signature(Ret (Class::*f)(Param...) volatile &noexcept)
+  Function_Signature(Ret (Class::*f)(Param...) volatile & noexcept)
       -> Function_Signature<Ret, Function_Params<volatile Class &, Param...>, true, true>;
 
   template<typename Ret, typename Class, typename... Param>
@@ -72,20 +72,20 @@ namespace chaiscript::dispatch::detail {
       -> Function_Signature<Ret, Function_Params<volatile const Class &, Param...>, false, true>;
 
   template<typename Ret, typename Class, typename... Param>
-  Function_Signature(Ret (Class::*f)(Param...) volatile const &noexcept)
+  Function_Signature(Ret (Class::*f)(Param...) volatile const & noexcept)
       -> Function_Signature<Ret, Function_Params<volatile const Class &, Param...>, true, true>;
 
   template<typename Ret, typename Class, typename... Param>
   Function_Signature(Ret (Class::*f)(Param...) &) -> Function_Signature<Ret, Function_Params<Class &, Param...>, false, true>;
 
   template<typename Ret, typename Class, typename... Param>
-  Function_Signature(Ret (Class::*f)(Param...) &noexcept) -> Function_Signature<Ret, Function_Params<Class &, Param...>, true, true>;
+  Function_Signature(Ret (Class::*f)(Param...) & noexcept) -> Function_Signature<Ret, Function_Params<Class &, Param...>, true, true>;
 
   template<typename Ret, typename Class, typename... Param>
   Function_Signature(Ret (Class::*f)(Param...) const &) -> Function_Signature<Ret, Function_Params<const Class &, Param...>, false, true>;
 
   template<typename Ret, typename Class, typename... Param>
-  Function_Signature(Ret (Class::*f)(Param...) const &noexcept) -> Function_Signature<Ret, Function_Params<const Class &, Param...>, true, true>;
+  Function_Signature(Ret (Class::*f)(Param...) const & noexcept) -> Function_Signature<Ret, Function_Params<const Class &, Param...>, true, true>;
 
   // && reference specifier
 
@@ -93,7 +93,7 @@ namespace chaiscript::dispatch::detail {
   Function_Signature(Ret (Class::*f)(Param...) volatile &&) -> Function_Signature<Ret, Function_Params<volatile Class &&, Param...>, false, true>;
 
   template<typename Ret, typename Class, typename... Param>
-  Function_Signature(Ret (Class::*f)(Param...) volatile &&noexcept)
+  Function_Signature(Ret (Class::*f)(Param...) volatile && noexcept)
       -> Function_Signature<Ret, Function_Params<volatile Class &&, Param...>, true, true>;
 
   template<typename Ret, typename Class, typename... Param>
@@ -101,20 +101,20 @@ namespace chaiscript::dispatch::detail {
       -> Function_Signature<Ret, Function_Params<volatile const Class &&, Param...>, false, true>;
 
   template<typename Ret, typename Class, typename... Param>
-  Function_Signature(Ret (Class::*f)(Param...) volatile const &&noexcept)
+  Function_Signature(Ret (Class::*f)(Param...) volatile const && noexcept)
       -> Function_Signature<Ret, Function_Params<volatile const Class &&, Param...>, true, true>;
 
   template<typename Ret, typename Class, typename... Param>
   Function_Signature(Ret (Class::*f)(Param...) &&) -> Function_Signature<Ret, Function_Params<Class &&, Param...>, false, true>;
 
   template<typename Ret, typename Class, typename... Param>
-  Function_Signature(Ret (Class::*f)(Param...) &&noexcept) -> Function_Signature<Ret, Function_Params<Class &&, Param...>, true, true>;
+  Function_Signature(Ret (Class::*f)(Param...) && noexcept) -> Function_Signature<Ret, Function_Params<Class &&, Param...>, true, true>;
 
   template<typename Ret, typename Class, typename... Param>
   Function_Signature(Ret (Class::*f)(Param...) const &&) -> Function_Signature<Ret, Function_Params<const Class &&, Param...>, false, true>;
 
   template<typename Ret, typename Class, typename... Param>
-  Function_Signature(Ret (Class::*f)(Param...) const &&noexcept)
+  Function_Signature(Ret (Class::*f)(Param...) const && noexcept)
       -> Function_Signature<Ret, Function_Params<const Class &&, Param...>, true, true>;
 
   template<typename Ret, typename Class>

include/chaiscript/dispatchkit/handle_return.hpp

@@ -126,7 +126,7 @@ namespace chaiscript {
       struct Handle_Return_Ref {
         template<typename T>
         static Boxed_Value handle(T &&r) {
-          return Boxed_Value(std::cref(r), true);
+          return Boxed_Value(std::cref(r), false);
         }
       };
 
@@ -170,8 +170,8 @@ namespace chaiscript {
       };
 
       /**
- * Used internally for handling a return value from a Proxy_Function call
- */
+       * Used internally for handling a return value from a Proxy_Function call
+       */
       template<>
       struct Handle_Return<Boxed_Number> {
         static Boxed_Value handle(const Boxed_Number &r) noexcept { return r.bv; }
@@ -182,8 +182,8 @@ namespace chaiscript {
       };
 
       /**
- * Used internally for handling a return value from a Proxy_Function call
- */
+       * Used internally for handling a return value from a Proxy_Function call
+       */
       template<>
       struct Handle_Return<void> {
         static Boxed_Value handle() { return void_var(); }

include/chaiscript/dispatchkit/operators.hpp

@@ -15,168 +15,168 @@
 #include "register_function.hpp"
 
 namespace chaiscript::bootstrap::operators {
-  template<typename T>
-  void assign(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs = rhs; }), "=");
   }
 
-  template<typename T>
-  void assign_bitwise_and(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_bitwise_and(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs &= rhs; }), "&=");
   }
 
-  template<typename T>
-  void assign_xor(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_xor(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs ^= rhs; }), "^=");
   }
 
-  template<typename T>
-  void assign_bitwise_or(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_bitwise_or(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs |= rhs; }), "|=");
   }
 
-  template<typename T>
-  void assign_difference(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_difference(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs -= rhs; }), "-=");
   }
 
-  template<typename T>
-  void assign_left_shift(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_left_shift(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs <<= rhs; }), "<<=");
   }
 
-  template<typename T>
-  void assign_product(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_product(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs <<= rhs; }), "*=");
   }
 
-  template<typename T>
-  void assign_quotient(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_quotient(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs /= rhs; }), "/=");
   }
 
-  template<typename T>
-  void assign_remainder(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_remainder(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs %= rhs; }), "%=");
   }
 
-  template<typename T>
-  void assign_right_shift(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_right_shift(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs >>= rhs; }), ">>=");
   }
 
-  template<typename T>
-  void assign_sum(Module &m) {
+  template<typename T, typename ModuleType>
+  void assign_sum(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs, const T &rhs) -> T & { return lhs += rhs; }), "+=");
   }
 
-  template<typename T>
-  void prefix_decrement(Module &m) {
+  template<typename T, typename ModuleType>
+  void prefix_decrement(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs) -> T & { return --lhs; }), "--");
   }
 
-  template<typename T>
-  void prefix_increment(Module &m) {
+  template<typename T, typename ModuleType>
+  void prefix_increment(ModuleType &m) {
     m.add(chaiscript::fun([](T &lhs) -> T & { return ++lhs; }), "++");
   }
 
-  template<typename T>
-  void equal(Module &m) {
+  template<typename T, typename ModuleType>
+  void equal(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs == rhs; }), "==");
   }
 
-  template<typename T>
-  void greater_than(Module &m) {
+  template<typename T, typename ModuleType>
+  void greater_than(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs > rhs; }), ">");
   }
 
-  template<typename T>
-  void greater_than_equal(Module &m) {
+  template<typename T, typename ModuleType>
+  void greater_than_equal(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs >= rhs; }), ">=");
   }
 
-  template<typename T>
-  void less_than(Module &m) {
+  template<typename T, typename ModuleType>
+  void less_than(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs < rhs; }), "<");
   }
 
-  template<typename T>
-  void less_than_equal(Module &m) {
+  template<typename T, typename ModuleType>
+  void less_than_equal(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs <= rhs; }), "<=");
   }
 
-  template<typename T>
-  void logical_compliment(Module &m) {
+  template<typename T, typename ModuleType>
+  void logical_compliment(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs) { return !lhs; }), "!");
   }
 
-  template<typename T>
-  void not_equal(Module &m) {
+  template<typename T, typename ModuleType>
+  void not_equal(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs != rhs; }), "!=");
   }
 
-  template<typename T>
-  void addition(Module &m) {
+  template<typename T, typename ModuleType>
+  void addition(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs + rhs; }), "+");
   }
 
-  template<typename T>
-  void unary_plus(Module &m) {
+  template<typename T, typename ModuleType>
+  void unary_plus(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs) { return +lhs; }), "+");
   }
 
-  template<typename T>
-  void subtraction(Module &m) {
+  template<typename T, typename ModuleType>
+  void subtraction(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs - rhs; }), "-");
   }
 
-  template<typename T>
-  void unary_minus(Module &m) {
+  template<typename T, typename ModuleType>
+  void unary_minus(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs) { return -lhs; }), "-");
   }
 
-  template<typename T>
-  void bitwise_and(Module &m) {
+  template<typename T, typename ModuleType>
+  void bitwise_and(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs & rhs; }), "&");
   }
 
-  template<typename T>
-  void bitwise_compliment(Module &m) {
+  template<typename T, typename ModuleType>
+  void bitwise_compliment(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs) { return ~lhs; }), "~");
   }
 
-  template<typename T>
-  void bitwise_xor(Module &m) {
+  template<typename T, typename ModuleType>
+  void bitwise_xor(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs ^ rhs; }), "^");
   }
 
-  template<typename T>
-  void bitwise_or(Module &m) {
+  template<typename T, typename ModuleType>
+  void bitwise_or(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs | rhs; }), "|");
   }
 
-  template<typename T>
-  void division(Module &m) {
+  template<typename T, typename ModuleType>
+  void division(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs / rhs; }), "/");
   }
 
-  template<typename T>
-  void left_shift(Module &m) {
+  template<typename T, typename ModuleType>
+  void left_shift(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs << rhs; }), "<<");
   }
 
-  template<typename T>
-  void multiplication(Module &m) {
+  template<typename T, typename ModuleType>
+  void multiplication(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs * rhs; }), "*");
   }
 
-  template<typename T>
-  void remainder(Module &m) {
+  template<typename T, typename ModuleType>
+  void remainder(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs % rhs; }), "%");
   }
 
-  template<typename T>
-  void right_shift(Module &m) {
+  template<typename T, typename ModuleType>
+  void right_shift(ModuleType &m) {
     m.add(chaiscript::fun([](const T &lhs, const T &rhs) { return lhs >> rhs; }), ">>");
   }
 } // namespace chaiscript::bootstrap::operators

include/chaiscript/dispatchkit/proxy_functions.hpp

@@ -65,7 +65,7 @@ namespace chaiscript {
       bool operator==(const Param_Types &t_rhs) const noexcept { return m_types == t_rhs.m_types; }
 
       std::vector<Boxed_Value> convert(Function_Params t_params, const Type_Conversions_State &t_conversions) const {
-        auto vals = t_params.to_vector();
+        auto vals = std::vector<Boxed_Value>{t_params.begin(), t_params.end()};
         const auto dynamic_object_type_info = user_type<Dynamic_Object>();
         for (size_t i = 0; i < vals.size(); ++i) {
           const auto &name = m_types[i].first;
@@ -165,13 +165,13 @@ namespace chaiscript {
     };
 
     /**
- * Pure virtual base class for all Proxy_Function implementations
- * Proxy_Functions are a type erasure of type safe C++
- * function calls. At runtime parameter types are expected to be
- * tested against passed in types.
- * Dispatch_Engine only knows how to work with Proxy_Function, no other
- * function classes.
- */
+     * Pure virtual base class for all Proxy_Function implementations
+     * Proxy_Functions are a type erasure of type safe C++
+     * function calls. At runtime parameter types are expected to be
+     * tested against passed in types.
+     * Dispatch_Engine only knows how to work with Proxy_Function, no other
+     * function classes.
+     */
     class Proxy_Function_Base {
     public:
       virtual ~Proxy_Function_Base() = default;
@@ -380,7 +380,15 @@ namespace chaiscript {
 
         for (const auto &t : t_types.types()) {
           if (t.second.is_undef()) {
-            types.push_back(chaiscript::detail::Get_Type_Info<Boxed_Value>::get());
+            if (!t.first.empty()) {
+              // Named type without C++ type_info — assumed to be a Dynamic_Object subtype.
+              // Using Dynamic_Object type_info ensures correct dispatch priority so that
+              // user-defined overrides on specific subtypes are tried before generic
+              // Dynamic_Object built-in functions.
+              types.push_back(user_type<Dynamic_Object>());
+            } else {
+              types.push_back(chaiscript::detail::Get_Type_Info<Boxed_Value>::get());
+            }
           } else {
             types.push_back(t.second);
           }
@@ -674,13 +682,13 @@ namespace chaiscript {
     public:
       dispatch_error(const Function_Params &t_parameters, std::vector<Const_Proxy_Function> t_functions)
           : std::runtime_error("Error with function dispatch")
-          , parameters(t_parameters.to_vector())
+          , parameters(t_parameters.begin(), t_parameters.end())
           , functions(std::move(t_functions)) {
       }
 
       dispatch_error(const Function_Params &t_parameters, std::vector<Const_Proxy_Function> t_functions, const std::string &t_desc)
           : std::runtime_error(t_desc)
-          , parameters(t_parameters.to_vector())
+          , parameters(t_parameters.begin(), t_parameters.end())
           , functions(std::move(t_functions)) {
       }
 
@@ -729,11 +737,24 @@ namespace chaiscript {
             if (matching_func == end) {
               matching_func = begin;
             } else {
-              // handle const members vs non-const member, which is not really ambiguous
               const auto &mat_fun_param_types = matching_func->second->get_param_types();
               const auto &next_fun_param_types = begin->second->get_param_types();
 
-              if (plist[0].is_const() && !mat_fun_param_types[1].is_const() && next_fun_param_types[1].is_const()) {
+              // Prefer the candidate whose first parameter (receiver) matches the
+              // actual receiver type exactly over one that needs a type conversion.
+              // Conversions on the receiver create temporaries, so any mutation
+              // would be silently lost; this mirrors the deprioritization in
+              // dispatch() and resolves cases like myString.substr(int, int) when
+              // both string::substr and string_view::substr are registered.
+              const bool plist_empty = plist.empty();
+              const bool mat_receiver_exact = !plist_empty && mat_fun_param_types[1].bare_equal(plist[0].get_type_info());
+              const bool next_receiver_exact = !plist_empty && next_fun_param_types[1].bare_equal(plist[0].get_type_info());
+
+              if (mat_receiver_exact && !next_receiver_exact) {
+                // keep the old one, it has the better receiver match
+              } else if (!mat_receiver_exact && next_receiver_exact) {
+                matching_func = begin; // keep the new one, it has the better receiver match
+              } else if (plist[0].is_const() && !mat_fun_param_types[1].is_const() && next_fun_param_types[1].is_const()) {
                 matching_func = begin; // keep the new one, the const/non-const matchup is correct
               } else if (!plist[0].is_const() && !mat_fun_param_types[1].is_const() && next_fun_param_types[1].is_const()) {
                 // keep the old one, it has a better const/non-const matchup
@@ -806,6 +827,30 @@ namespace chaiscript {
             numdiffs = plist.size();
           }
 
+          // Deprioritize C++ registered generic Dynamic_Object functions when the
+          // actual first argument is a specific Dynamic_Object subtype.  This allows
+          // user-defined operator overrides (e.g. `[]`) on a subtype to take precedence
+          // over the built-in Dynamic_Object operations such as get_attr.
+          // Only deprioritize non-dynamic (C++ registered) functions — ChaiScript-defined
+          // functions (Dynamic_Proxy_Function) have their own type matching via Param_Types.
+          if (!plist.empty()
+              && dynamic_cast<const Dynamic_Proxy_Function *>(func.get()) == nullptr) {
+            static const auto dynamic_object_ti = user_type<Dynamic_Object>();
+            if (func->get_param_types().size() > 1
+                && func->get_param_types()[1].bare_equal(dynamic_object_ti)
+                && plist[0].get_type_info().bare_equal(dynamic_object_ti)
+                && func->dynamic_object_type_name().empty()) {
+              try {
+                const auto &d = boxed_cast<const Dynamic_Object &>(plist[0], &t_conversions);
+                if (d.get_type_name() != "Dynamic_Object") {
+                  numdiffs = plist.size();
+                }
+              } catch (const std::bad_cast &) {
+                // not a Dynamic_Object, ignore
+              }
+            }
+          }
+
           ordered_funcs.emplace_back(numdiffs, func.get());
         }
       }

include/chaiscript/dispatchkit/proxy_functions_detail.hpp

@@ -32,9 +32,9 @@ namespace chaiscript {
 namespace chaiscript {
   namespace exception {
     /**
- * Exception thrown when there is a mismatch in number of
- * parameters during Proxy_Function execution
- */
+     * Exception thrown when there is a mismatch in number of
+     * parameters during Proxy_Function execution
+     */
     struct arity_error : std::range_error {
       arity_error(int t_got, int t_expected)
           : std::range_error("Function dispatch arity mismatch")
@@ -54,9 +54,9 @@ namespace chaiscript {
   namespace dispatch {
     namespace detail {
       /**
- * Used by Proxy_Function_Impl to return a list of all param types
- * it contains.
- */
+       * Used by Proxy_Function_Impl to return a list of all param types
+       * it contains.
+       */
       template<typename Ret, typename... Params>
       std::vector<Type_Info> build_param_type_list(Ret (*)(Params...)) {
         /// \note somehow this is responsible for a large part of the code generation
@@ -64,10 +64,10 @@ namespace chaiscript {
       }
 
       /**
- * Used by Proxy_Function_Impl to determine if it is equivalent to another
- * Proxy_Function_Impl object. This function is primarily used to prevent
- * registration of two functions with the exact same signatures
- */
+       * Used by Proxy_Function_Impl to determine if it is equivalent to another
+       * Proxy_Function_Impl object. This function is primarily used to prevent
+       * registration of two functions with the exact same signatures
+       */
       template<typename Ret, typename... Params>
       bool compare_types_cast(Ret (*)(Params...), const chaiscript::Function_Params &params, const Type_Conversions_State &t_conversions) noexcept {
         try {
@@ -80,11 +80,11 @@ namespace chaiscript {
       }
 
       template<typename Callable, typename Ret, typename... Params, size_t... I>
-      Ret call_func(Ret (*)(Params...),
-                    std::index_sequence<I...>,
-                    const Callable &f,
-                    [[maybe_unused]] const chaiscript::Function_Params &params,
-                    [[maybe_unused]] const Type_Conversions_State &t_conversions) {
+      Ret call_func_impl(Ret (*)(Params...),
+                         std::index_sequence<I...>,
+                         const Callable &f,
+                         [[maybe_unused]] const chaiscript::Function_Params &params,
+                         [[maybe_unused]] const Type_Conversions_State &t_conversions) {
         return f(boxed_cast<Params>(params[I], &t_conversions)...);
       }
 
@@ -95,14 +95,24 @@ namespace chaiscript {
       template<typename Callable, typename Ret, typename... Params>
       Boxed_Value
       call_func(Ret (*sig)(Params...), const Callable &f, const chaiscript::Function_Params &params, const Type_Conversions_State &t_conversions) {
-        if constexpr (std::is_same_v<Ret, void>) {
-          call_func(sig, std::index_sequence_for<Params...>{}, f, params, t_conversions);
-          return Handle_Return<void>::handle();
-        } else {
-          return Handle_Return<Ret>::handle(call_func(sig, std::index_sequence_for<Params...>{}, f, params, t_conversions));
-        }
+        return Handle_Return<Ret>::handle(call_func_impl(sig, std::index_sequence_for<Params...>{}, f, params, t_conversions));
       }
 
+// MSVC has a broken warning for unreachable code in this block
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4702)
+#endif
+      template<typename Callable, typename... Params>
+      Boxed_Value
+      call_func(void (*sig)(Params...), const Callable &f, const chaiscript::Function_Params &params, const Type_Conversions_State &t_conversions) {
+        call_func_impl(sig, std::index_sequence_for<Params...>{}, f, params, t_conversions);
+        return Handle_Return<void>::handle();
+      }
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
     } // namespace detail
   } // namespace dispatch
 

include/chaiscript/dispatchkit/register_function.hpp

@@ -82,6 +82,43 @@ namespace chaiscript {
     return dispatch::detail::make_callable(std::forward<T>(t), dispatch::detail::function_signature(t));
   }
 
+  /// \brief Creates a new Proxy_Function object from an overloaded free function, with the
+  ///        signature specified explicitly to disambiguate the overload.
+  ///
+  /// \b Example:
+  /// \code
+  /// int overloaded(int);
+  /// double overloaded(double);
+  ///
+  /// chai.add(chaiscript::fun<int(int)>(&overloaded), "overloaded");
+  /// chai.add(chaiscript::fun<double(double)>(&overloaded), "overloaded");
+  /// \endcode
+  template<typename Sig, std::enable_if_t<std::is_function_v<Sig>, int> = 0>
+  Proxy_Function fun(std::type_identity_t<Sig> *f) {
+    return dispatch::detail::make_callable(f, dispatch::detail::function_signature(f));
+  }
+
+  /// \brief Creates a new Proxy_Function object from an overloaded member function, with the
+  ///        signature specified explicitly to disambiguate the overload.
+  ///
+  /// \b Example:
+  /// \code
+  /// class MyClass {
+  ///   public:
+  ///     int overloaded(int);
+  ///     double overloaded(double);
+  ///     int const_overloaded() const;
+  /// };
+  ///
+  /// chai.add(chaiscript::fun<int(int)>(&MyClass::overloaded), "overloaded");
+  /// chai.add(chaiscript::fun<double(double)>(&MyClass::overloaded), "overloaded");
+  /// chai.add(chaiscript::fun<int() const>(&MyClass::const_overloaded), "const_overloaded");
+  /// \endcode
+  template<typename Sig, typename Class, std::enable_if_t<std::is_function_v<Sig>, int> = 0>
+  Proxy_Function fun(std::type_identity_t<Sig> Class::*f) {
+    return dispatch::detail::make_callable(f, dispatch::detail::function_signature(f));
+  }
+
   /// \brief Creates a new Proxy_Function object from a free function, member function or data member and binds the first parameter of it
   /// \param[in] t Function / member to expose
   /// \param[in] q Value to bind to first parameter

include/chaiscript/dispatchkit/short_alloc.hpp

@@ -1,137 +0,0 @@
-#ifndef SHORT_ALLOC_H
-#define SHORT_ALLOC_H
-
-// The MIT License (MIT)
-//
-// Copyright (c) 2015 Howard Hinnant
-//
-// 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 <cassert>
-#include <cstddef>
-
-template<std::size_t N, std::size_t alignment = alignof(std::max_align_t)>
-class arena {
-  alignas(alignment) char buf_[N];
-  char *ptr_;
-
-public:
-  ~arena() { ptr_ = nullptr; }
-  arena() noexcept
-      : ptr_(buf_) {
-  }
-  arena(const arena &) = delete;
-  arena &operator=(const arena &) = delete;
-
-  template<std::size_t ReqAlign>
-  char *allocate(std::size_t n);
-  void deallocate(char *p, std::size_t n) noexcept;
-
-  static constexpr std::size_t size() noexcept { return N; }
-  std::size_t used() const noexcept { return static_cast<std::size_t>(ptr_ - buf_); }
-  void reset() noexcept { ptr_ = buf_; }
-
-private:
-  static std::size_t align_up(std::size_t n) noexcept { return (n + (alignment - 1)) & ~(alignment - 1); }
-
-  bool pointer_in_buffer(char *p) noexcept { return buf_ <= p && p <= buf_ + N; }
-};
-
-template<std::size_t N, std::size_t alignment>
-template<std::size_t ReqAlign>
-char *arena<N, alignment>::allocate(std::size_t n) {
-  static_assert(ReqAlign <= alignment, "alignment is too small for this arena");
-  assert(pointer_in_buffer(ptr_) && "short_alloc has outlived arena");
-  auto const aligned_n = align_up(n);
-  if (static_cast<decltype(aligned_n)>(buf_ + N - ptr_) >= aligned_n) {
-    char *r = ptr_;
-    ptr_ += aligned_n;
-    return r;
-  }
-
-  static_assert(alignment <= alignof(std::max_align_t),
-                "you've chosen an "
-                "alignment that is larger than alignof(std::max_align_t), and "
-                "cannot be guaranteed by normal operator new");
-  return static_cast<char *>(::operator new(n));
-}
-
-template<std::size_t N, std::size_t alignment>
-void arena<N, alignment>::deallocate(char *p, std::size_t n) noexcept {
-  assert(pointer_in_buffer(ptr_) && "short_alloc has outlived arena");
-  if (pointer_in_buffer(p)) {
-    n = align_up(n);
-    if (p + n == ptr_) {
-      ptr_ = p;
-    }
-  } else {
-    ::operator delete(p);
-  }
-}
-
-template<class T, std::size_t N, std::size_t Align = alignof(std::max_align_t)>
-class short_alloc {
-public:
-  using value_type = T;
-  static auto constexpr alignment = Align;
-  static auto constexpr size = N;
-  using arena_type = arena<size, alignment>;
-
-private:
-  arena_type &a_;
-
-public:
-  short_alloc(const short_alloc &) = default;
-  short_alloc &operator=(const short_alloc &) = delete;
-
-  explicit short_alloc(arena_type &a) noexcept
-      : a_(a) {
-    static_assert(size % alignment == 0, "size N needs to be a multiple of alignment Align");
-  }
-  template<class U>
-  explicit short_alloc(const short_alloc<U, N, alignment> &a) noexcept
-      : a_(a.a_) {
-  }
-
-  template<class _Up>
-  struct rebind {
-    using other = short_alloc<_Up, N, alignment>;
-  };
-
-  T *allocate(std::size_t n) { return reinterpret_cast<T *>(a_.template allocate<alignof(T)>(n * sizeof(T))); }
-  void deallocate(T *p, std::size_t n) noexcept { a_.deallocate(reinterpret_cast<char *>(p), n * sizeof(T)); }
-
-  template<class T1, std::size_t N1, std::size_t A1, class U, std::size_t M, std::size_t A2>
-  friend bool operator==(const short_alloc<T1, N1, A1> &x, const short_alloc<U, M, A2> &y) noexcept;
-
-  template<class U, std::size_t M, std::size_t A>
-  friend class short_alloc;
-};
-
-template<class T, std::size_t N, std::size_t A1, class U, std::size_t M, std::size_t A2>
-inline bool operator==(const short_alloc<T, N, A1> &x, const short_alloc<U, M, A2> &y) noexcept {
-  return N == M && A1 == A2 && &x.a_ == &y.a_;
-}
-
-template<class T, std::size_t N, std::size_t A1, class U, std::size_t M, std::size_t A2>
-inline bool operator!=(const short_alloc<T, N, A1> &x, const short_alloc<U, M, A2> &y) noexcept {
-  return !(x == y);
-}
-
-#endif // SHORT_ALLOC_HPP

include/chaiscript/dispatchkit/type_conversions.hpp

@@ -498,6 +498,29 @@ namespace chaiscript {
                                                                                                                func);
   }
 
+  namespace detail {
+    template<typename T>
+    struct is_std_vector : std::false_type {};
+
+    template<typename T, typename A>
+    struct is_std_vector<std::vector<T, A>> : std::true_type {};
+
+    template<typename T>
+    T convert_vector_element(const Boxed_Value &bv) {
+      if constexpr (is_std_vector<T>::value) {
+        const auto &inner = Cast_Helper<const std::vector<Boxed_Value> &>::cast(bv, nullptr);
+        T result;
+        result.reserve(inner.size());
+        for (const Boxed_Value &elem : inner) {
+          result.push_back(convert_vector_element<typename T::value_type>(elem));
+        }
+        return result;
+      } else {
+        return Cast_Helper<T>::cast(bv, nullptr);
+      }
+    }
+  } // namespace detail
+
   template<typename To>
   Type_Conversion vector_conversion() {
     auto func = [](const Boxed_Value &t_bv) -> Boxed_Value {
@@ -506,7 +529,7 @@ namespace chaiscript {
       To vec;
       vec.reserve(from_vec.size());
       for (const Boxed_Value &bv : from_vec) {
-        vec.push_back(detail::Cast_Helper<typename To::value_type>::cast(bv, nullptr));
+        vec.push_back(detail::convert_vector_element<typename To::value_type>(bv));
       }
 
       return Boxed_Value(std::move(vec));
@@ -542,9 +565,8 @@ namespace chaiscript {
           = detail::Cast_Helper<const std::pair<Boxed_Value, Boxed_Value> &>::cast(t_bv, nullptr);
 
       auto pair = std::make_pair(
-        detail::Cast_Helper<Left>::cast(from_pair.first, nullptr),
-        detail::Cast_Helper<Right>::cast(from_pair.second, nullptr)
-      );
+          detail::Cast_Helper<Left>::cast(from_pair.first, nullptr),
+          detail::Cast_Helper<Right>::cast(from_pair.second, nullptr));
 
       return Boxed_Value(std::move(pair));
     };

include/chaiscript/language/chaiscript_algebraic.hpp

@@ -12,6 +12,7 @@
 
 #include "../utility/hash.hpp"
 
+#include <array>
 #include <string>
 
 namespace chaiscript {
@@ -52,10 +53,10 @@ namespace chaiscript {
       invalid
     };
 
-    constexpr static const char *to_string(Opers t_oper) noexcept {
-      constexpr const char *opers[]
+    constexpr static std::string_view to_string(Opers t_oper) noexcept {
+      constexpr const std::array opers
           = {"", "==", "<", ">", "<=", ">=", "!=", "", "=", "++", "--", "*=", "+=", "/=", "-=", "", "&=", "|=", "<<=", ">>=", "%=", "^=", "", "<<", ">>", "%", "&", "|", "^", "~", "", "+", "/", "*", "-", "+", "-", ""};
-      return opers[static_cast<int>(t_oper)];
+      return opers[static_cast<std::size_t>(t_oper)];
     }
 
     constexpr static Opers to_operator(std::string_view t_str, bool t_is_unary = false) noexcept {

include/chaiscript/language/chaiscript_common.hpp

@@ -33,7 +33,7 @@ namespace chaiscript {
     template<typename T>
     static bool is_reserved_word(const T &s) noexcept {
       const static std::unordered_set<std::uint32_t>
-          words{utility::hash("def"), utility::hash("fun"), utility::hash("while"), utility::hash("for"), utility::hash("if"), utility::hash("else"), utility::hash("&&"), utility::hash("||"), utility::hash(","), utility::hash("auto"), utility::hash("return"), utility::hash("break"), utility::hash("true"), utility::hash("false"), utility::hash("class"), utility::hash("attr"), utility::hash("var"), utility::hash("global"), utility::hash("GLOBAL"), utility::hash("_"), utility::hash("__LINE__"), utility::hash("__FILE__"), utility::hash("__FUNC__"), utility::hash("__CLASS__"), utility::hash("const")};
+          words{utility::hash("def"), utility::hash("fun"), utility::hash("while"), utility::hash("for"), utility::hash("if"), utility::hash("else"), utility::hash("&&"), utility::hash("||"), utility::hash(","), utility::hash("auto"), utility::hash("return"), utility::hash("break"), utility::hash("true"), utility::hash("false"), utility::hash("class"), utility::hash("attr"), utility::hash("var"), utility::hash("global"), utility::hash("GLOBAL"), utility::hash("_"), utility::hash("__LINE__"), utility::hash("__FILE__"), utility::hash("__FUNC__"), utility::hash("__CLASS__"), utility::hash("const"), utility::hash("using"), utility::hash("enum")};
 
       return words.count(utility::hash(s)) == 1;
     }
@@ -106,7 +106,10 @@ namespace chaiscript {
     Constant,
     Compiled,
     Const_Var_Decl,
-    Const_Assign_Decl
+    Const_Assign_Decl,
+    Using,
+    Enum,
+    Namespace_Block
   };
 
   enum class Operator_Precedence {
@@ -127,9 +130,9 @@ namespace chaiscript {
   namespace {
     /// Helper lookup to get the name of each node type
     constexpr const char *ast_node_type_to_string(AST_Node_Type ast_node_type) noexcept {
-      constexpr const char *const ast_node_types[] = {"Id", "Fun_Call", "Unused_Return_Fun_Call", "Arg_List", "Equation", "Var_Decl", "Assign_Decl", "Array_Call", "Dot_Access", "Lambda", "Block", "Scopeless_Block", "Def", "While", "If", "For", "Ranged_For", "Inline_Array", "Inline_Map", "Return", "File", "Prefix", "Break", "Continue", "Map_Pair", "Value_Range", "Inline_Range", "Try", "Catch", "Finally", "Method", "Attr_Decl", "Logical_And", "Logical_Or", "Reference", "Switch", "Case", "Default", "Noop", "Class", "Binary", "Arg", "Global_Decl", "Constant", "Compiled", "Const_Var_Decl", "Const_Assign_Decl"};
+      constexpr std::array ast_node_types = {"Id", "Fun_Call", "Unused_Return_Fun_Call", "Arg_List", "Equation", "Var_Decl", "Assign_Decl", "Array_Call", "Dot_Access", "Lambda", "Block", "Scopeless_Block", "Def", "While", "If", "For", "Ranged_For", "Inline_Array", "Inline_Map", "Return", "File", "Prefix", "Break", "Continue", "Map_Pair", "Value_Range", "Inline_Range", "Try", "Catch", "Finally", "Method", "Attr_Decl", "Logical_And", "Logical_Or", "Reference", "Switch", "Case", "Default", "Noop", "Class", "Binary", "Arg", "Global_Decl", "Constant", "Compiled", "Const_Var_Decl", "Const_Assign_Decl", "Using", "Enum", "Namespace_Block"};
 
-      return ast_node_types[static_cast<int>(ast_node_type)];
+      return ast_node_types[static_cast<std::size_t>(ast_node_type)];
     }
   } // namespace
 
@@ -590,13 +593,13 @@ namespace chaiscript {
 
   } // namespace exception
 
-  //static
+  // static
   bool AST_Node::get_bool_condition(const Boxed_Value &t_bv, const chaiscript::detail::Dispatch_State &t_ss) {
-      try {
-        return t_ss->boxed_cast<bool>(t_bv);
-      } catch (const exception::bad_boxed_cast &) {
-        throw exception::eval_error("Condition not boolean");
-      }
+    try {
+      return t_ss->boxed_cast<bool>(t_bv);
+    } catch (const exception::bad_boxed_cast &) {
+      throw exception::eval_error("Condition not boolean");
+    }
   }
 
   namespace parser {

include/chaiscript/language/chaiscript_engine.hpp

@@ -15,6 +15,7 @@
 #include <exception>
 #include <fstream>
 #include <functional>
+#include <future>
 #include <map>
 #include <memory>
 #include <mutex>
@@ -78,6 +79,9 @@ namespace chaiscript {
 
     std::map<std::string, std::function<Namespace &()>> m_namespace_generators;
 
+    std::function<void(const std::string &)> m_print_handler = [](const std::string &) noexcept {};
+    std::function<std::string(const std::string &)> m_file_reader;
+
     /// Evaluates the given string in by parsing it and running the results through the evaluator
     Boxed_Value do_eval(const std::string &t_input, const std::string &t_filename = "__EVAL__", bool /* t_internal*/ = false) {
       try {
@@ -118,11 +122,30 @@ namespace chaiscript {
     chaiscript::detail::Dispatch_Engine &get_eval_engine() noexcept { return m_engine; }
 
     /// Builds all the requirements for ChaiScript, including its evaluator and a run of its prelude.
-    void build_eval_system(const ModulePtr &t_lib, const std::vector<Options> &t_opts) {
+    void build_eval_system(const ModulePtr &t_lib, const std::vector<Options> &t_opts, const bool t_no_io) {
       if (t_lib) {
         add(t_lib);
       }
 
+      if (!t_no_io) {
+        m_print_handler = [](const std::string &s) noexcept {
+          fwrite(s.c_str(), 1, s.size(), stdout);
+        };
+      }
+
+      m_engine.add(fun([this](const std::string &s) { m_print_handler(s); }), "print_string");
+      m_engine.add(fun([this](const std::string &s) { m_print_handler(s + "\n"); }), "println_string");
+
+      m_engine.add(fun([this](const std::function<void(const std::string &)> &t_handler) {
+                     m_print_handler = t_handler;
+                   }),
+                   "set_print_handler");
+
+      m_engine.add(fun([this](const std::function<std::string(const std::string &)> &t_reader) {
+                     m_file_reader = t_reader;
+                   }),
+                   "set_file_reader");
+
       m_engine.add(fun([this]() { m_engine.dump_system(); }), "dump_system");
       m_engine.add(fun([this](const Boxed_Value &t_bv) { m_engine.dump_object(t_bv); }), "dump_object");
       m_engine.add(fun([this](const Boxed_Value &t_bv, const std::string &t_type) { return m_engine.is_type(t_bv, t_type); }), "is_type");
@@ -172,13 +195,39 @@ namespace chaiscript {
       m_engine.add(fun([this](const Boxed_Value &t_bv, const std::string &t_name) { add_global(t_bv, t_name); }), "add_global");
       m_engine.add(fun([this](const Boxed_Value &t_bv, const std::string &t_name) { set_global(t_bv, t_name); }), "set_global");
 
-      // why this unused parameter to Namespace?
       m_engine.add(fun([this](const std::string &t_namespace_name) {
-                     register_namespace([](Namespace & /*space*/) noexcept {}, t_namespace_name);
-                     import(t_namespace_name);
+                     if (!m_namespace_generators.count(t_namespace_name)) {
+                       register_namespace([](Namespace & /*space*/) noexcept {}, t_namespace_name);
+                     }
+                     const auto sep_pos = t_namespace_name.find("::");
+                     const std::string root_name = (sep_pos != std::string::npos) ? t_namespace_name.substr(0, sep_pos) : t_namespace_name;
+                     if (!m_engine.get_scripting_objects().count(root_name)) {
+                       import(root_name);
+                     } else if (m_namespace_generators.count(root_name)) {
+                       nest_children(root_name, m_namespace_generators[root_name]());
+                     }
                    }),
                    "namespace");
       m_engine.add(fun([this](const std::string &t_namespace_name) { import(t_namespace_name); }), "import");
+
+#ifndef CHAISCRIPT_NO_THREADS
+      // Register async() with thread tracking so the engine can join all
+      // async threads before destroying shared state (issues #632, #636).
+      m_engine.add(chaiscript::fun(
+                       [this](const std::function<chaiscript::Boxed_Value()> &t_func) {
+                         auto promise_ptr = std::make_shared<std::promise<chaiscript::Boxed_Value>>();
+                         auto future = promise_ptr->get_future();
+                         m_engine.track_async_thread(std::thread([promise_ptr, t_func]() {
+                           try {
+                             promise_ptr->set_value(t_func());
+                           } catch (...) {
+                             promise_ptr->set_exception(std::current_exception());
+                           }
+                         }));
+                         return future;
+                       }),
+                   "async");
+#endif
     }
 
     /// Skip BOM at the beginning of file
@@ -201,7 +250,15 @@ namespace chaiscript {
     }
 
     /// Helper function for loading a file
-    static std::string load_file(const std::string &t_filename) {
+    std::string load_file(const std::string &t_filename) const {
+      if (m_file_reader) {
+        return m_file_reader(t_filename);
+      }
+
+      return load_file_default(t_filename);
+    }
+
+    static std::string load_file_default(const std::string &t_filename) {
       std::ifstream infile(t_filename.c_str(), std::ios::in | std::ios::ate | std::ios::binary);
 
       if (!infile.is_open()) {
@@ -236,6 +293,17 @@ namespace chaiscript {
     }
 
   public:
+    /// \brief Set a custom handler for print output, used by both print_string and println_string
+    /// \param[in] t_handler Function to call with the string to print
+    void set_print_handler(std::function<void(const std::string &)> t_handler) {
+      m_print_handler = std::move(t_handler);
+    }
+
+    /// \brief Set a custom handler for reading files, used by eval_file, use, and internal_eval_file
+    /// \param[in] t_reader Function to call with the filename, returning the file contents as a string
+    void set_file_reader(std::function<std::string(const std::string &)> t_reader) {
+      m_file_reader = std::move(t_reader);
+    }
 
     /// \brief Virtual destructor for ChaiScript
     virtual ~ChaiScript_Basic() = default;
@@ -248,7 +316,8 @@ namespace chaiscript {
                      std::unique_ptr<parser::ChaiScript_Parser_Base> &&parser,
                      std::vector<std::string> t_module_paths = {},
                      std::vector<std::string> t_use_paths = {},
-                     const std::vector<chaiscript::Options> &t_opts = chaiscript::default_options())
+                     const std::vector<chaiscript::Options> &t_opts = chaiscript::default_options(),
+                     const bool t_no_io = false)
         : m_module_paths(ensure_minimum_path_vec(std::move(t_module_paths)))
         , m_use_paths(ensure_minimum_path_vec(std::move(t_use_paths)))
         , m_parser(std::move(parser))
@@ -283,7 +352,7 @@ namespace chaiscript {
         m_module_paths.insert(m_module_paths.begin(), dllpath + "/");
       }
 #endif
-      build_eval_system(t_lib, t_opts);
+      build_eval_system(t_lib, t_opts, t_no_io);
     }
 
 #ifndef CHAISCRIPT_NO_DYNLOAD
@@ -542,7 +611,7 @@ namespace chaiscript {
     /// (the symbol mentioned above), an exception is thrown.
     ///
     /// \throw chaiscript::exception::load_module_error In the event that no matching module can be found.
-    std::string load_module(const std::string &t_module_name) {
+    std::string load_module([[maybe_unused]] const std::string &t_module_name) {
 #ifdef CHAISCRIPT_NO_DYNLOAD
       throw chaiscript::exception::load_module_error("Loadable module support was disabled (CHAISCRIPT_NO_DYNLOAD)");
 #else
@@ -688,28 +757,59 @@ namespace chaiscript {
       if (m_engine.get_scripting_objects().count(t_namespace_name)) {
         throw std::runtime_error("Namespace: " + t_namespace_name + " was already defined");
       } else if (m_namespace_generators.count(t_namespace_name)) {
-        m_engine.add_global(var(std::ref(m_namespace_generators[t_namespace_name]())), t_namespace_name);
+        auto &ns = m_namespace_generators[t_namespace_name]();
+        nest_children(t_namespace_name, ns);
+        m_engine.add_global(var(std::ref(ns)), t_namespace_name);
       } else {
         throw std::runtime_error("No registered namespace: " + t_namespace_name);
       }
     }
 
     /// \brief Registers a namespace generator, which delays generation of the namespace until it is imported, saving memory if it is never
-    /// used. \param[in] t_namespace_generator Namespace generator function. \param[in] t_namespace_name Name of the Namespace function
-    /// being registered. \throw std::runtime_error In the case that the namespace name was already registered.
+    /// used. Supports C++-style nested names (e.g. "constants::si") for nested namespaces; parent namespaces are auto-registered if absent.
+    /// \param[in] t_namespace_generator Namespace generator function.
+    /// \param[in] t_namespace_name Name of the Namespace function being registered (may contain :: for nesting).
+    /// \throw std::runtime_error In the case that the namespace name was already registered.
     void register_namespace(const std::function<void(Namespace &)> &t_namespace_generator, const std::string &t_namespace_name) {
       chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
 
-      if (!m_namespace_generators.count(t_namespace_name)) {
-        // contain the namespace object memory within the m_namespace_generators map
-        m_namespace_generators.emplace(std::make_pair(t_namespace_name, [=, space = Namespace()]() mutable -> Namespace & {
-          t_namespace_generator(space);
-          return space;
-        }));
-      } else {
+      if (m_namespace_generators.count(t_namespace_name)) {
         throw std::runtime_error("Namespace: " + t_namespace_name + " was already registered.");
       }
+
+      m_namespace_generators.emplace(std::make_pair(t_namespace_name, [=, space = Namespace()]() mutable noexcept -> Namespace & {
+        t_namespace_generator(space);
+        return space;
+      }));
+
+      auto pos = t_namespace_name.rfind("::");
+      while (pos != std::string::npos) {
+        const std::string parent = t_namespace_name.substr(0, pos);
+        if (!m_namespace_generators.count(parent)) {
+          m_namespace_generators.emplace(std::make_pair(parent, [space = Namespace()]() mutable noexcept -> Namespace & {
+            return space;
+          }));
+        }
+        pos = parent.rfind("::");
+      }
     }
+
+  private:
+    void nest_children(const std::string &t_parent_name, Namespace &t_parent) {
+      const std::string prefix = t_parent_name + "::";
+      for (auto &[name, generator] : m_namespace_generators) {
+        if (name.size() > prefix.size() && name.compare(0, prefix.size(), prefix) == 0) {
+          const std::string remainder = name.substr(prefix.size());
+          if (remainder.find("::") == std::string::npos) {
+            auto &child_ns = generator();
+            nest_children(name, child_ns);
+            t_parent[remainder] = var(std::ref(child_ns));
+          }
+        }
+      }
+    }
+
+  public:
   };
 
 } // namespace chaiscript

include/chaiscript/language/chaiscript_eval.hpp

@@ -10,6 +10,7 @@
 #ifndef CHAISCRIPT_EVAL_HPP_
 #define CHAISCRIPT_EVAL_HPP_
 
+#include <algorithm>
 #include <exception>
 #include <functional>
 #include <limits>
@@ -108,6 +109,169 @@ namespace chaiscript {
           return incoming;
         }
       }
+      class Strong_Typedef_Binary_Op final : public dispatch::Proxy_Function_Base {
+      public:
+        Strong_Typedef_Binary_Op(
+            std::string t_type_name,
+            std::string t_op_name,
+            Operators::Opers t_oper,
+            bool t_rewrap,
+            chaiscript::detail::Dispatch_Engine &t_engine)
+            : Proxy_Function_Base(
+                  {chaiscript::detail::Get_Type_Info<Boxed_Value>::get(),
+                   user_type<dispatch::Dynamic_Object>(),
+                   user_type<dispatch::Dynamic_Object>()},
+                  2)
+            , m_type_name(std::move(t_type_name))
+            , m_op_name(std::move(t_op_name))
+            , m_oper(t_oper)
+            , m_rewrap(t_rewrap)
+            , m_engine(t_engine) {
+        }
+
+        bool operator==(const Proxy_Function_Base &f) const noexcept override {
+          if (const auto *other = dynamic_cast<const Strong_Typedef_Binary_Op *>(&f)) {
+            return m_type_name == other->m_type_name && m_op_name == other->m_op_name;
+          }
+          return false;
+        }
+
+        bool call_match(const Function_Params &vals, const Type_Conversions_State &t_conversions) const noexcept override {
+          return vals.size() == 2
+              && type_matches(vals[0], t_conversions)
+              && type_matches(vals[1], t_conversions);
+        }
+
+      protected:
+        Boxed_Value do_call(const Function_Params &params, const Type_Conversions_State &t_conversions) const override {
+          if (!call_match(params, t_conversions)) {
+            throw chaiscript::exception::guard_error();
+          }
+
+          const auto &lhs = boxed_cast<const dispatch::Dynamic_Object &>(params[0], &t_conversions);
+          const auto &rhs = boxed_cast<const dispatch::Dynamic_Object &>(params[1], &t_conversions);
+          const auto lhs_val = lhs.get_attr("__value");
+          const auto rhs_val = rhs.get_attr("__value");
+
+          Boxed_Value result;
+          if (m_oper != Operators::Opers::invalid
+              && lhs_val.get_type_info().is_arithmetic()
+              && rhs_val.get_type_info().is_arithmetic()) {
+            result = Boxed_Number::do_oper(m_oper, lhs_val, rhs_val);
+          } else {
+            std::array<Boxed_Value, 2> underlying_params{lhs_val, rhs_val};
+            result = m_engine.call_function(m_op_name, m_loc, Function_Params(underlying_params), t_conversions);
+          }
+
+          if (m_rewrap) {
+            auto bv = Boxed_Value(dispatch::Dynamic_Object(m_type_name), true);
+            auto *obj = static_cast<dispatch::Dynamic_Object *>(bv.get_ptr());
+            obj->get_attr("__value") = result;
+            return bv;
+          }
+          return result;
+        }
+
+      private:
+        bool type_matches(const Boxed_Value &bv, const Type_Conversions_State &t_conversions) const noexcept {
+          if (!bv.get_type_info().bare_equal(user_type<dispatch::Dynamic_Object>())) {
+            return false;
+          }
+          try {
+            const auto &d = boxed_cast<const dispatch::Dynamic_Object &>(bv, &t_conversions);
+            return d.get_type_name() == m_type_name;
+          } catch (...) {
+            return false;
+          }
+        }
+
+        std::string m_type_name;
+        std::string m_op_name;
+        Operators::Opers m_oper;
+        bool m_rewrap;
+        chaiscript::detail::Dispatch_Engine &m_engine;
+        mutable std::atomic_uint_fast32_t m_loc{0};
+      };
+
+      class Strong_Typedef_Compound_Assign_Op final : public dispatch::Proxy_Function_Base {
+      public:
+        Strong_Typedef_Compound_Assign_Op(
+            std::string t_type_name,
+            std::string t_op_name,
+            Operators::Opers t_base_oper,
+            std::string t_base_op_name,
+            chaiscript::detail::Dispatch_Engine &t_engine)
+            : Proxy_Function_Base(
+                  {user_type<dispatch::Dynamic_Object>(),
+                   user_type<dispatch::Dynamic_Object>(),
+                   user_type<dispatch::Dynamic_Object>()},
+                  2)
+            , m_type_name(std::move(t_type_name))
+            , m_op_name(std::move(t_op_name))
+            , m_base_oper(t_base_oper)
+            , m_base_op_name(std::move(t_base_op_name))
+            , m_engine(t_engine) {
+        }
+
+        bool operator==(const Proxy_Function_Base &f) const noexcept override {
+          if (const auto *other = dynamic_cast<const Strong_Typedef_Compound_Assign_Op *>(&f)) {
+            return m_type_name == other->m_type_name && m_op_name == other->m_op_name;
+          }
+          return false;
+        }
+
+        bool call_match(const Function_Params &vals, const Type_Conversions_State &t_conversions) const noexcept override {
+          return vals.size() == 2
+              && type_matches(vals[0], t_conversions)
+              && type_matches(vals[1], t_conversions);
+        }
+
+      protected:
+        Boxed_Value do_call(const Function_Params &params, const Type_Conversions_State &t_conversions) const override {
+          if (!call_match(params, t_conversions)) {
+            throw chaiscript::exception::guard_error();
+          }
+
+          auto &lhs = boxed_cast<dispatch::Dynamic_Object &>(params[0], &t_conversions);
+          const auto &rhs = boxed_cast<const dispatch::Dynamic_Object &>(params[1], &t_conversions);
+          const auto lhs_val = lhs.get_attr("__value");
+          const auto rhs_val = rhs.get_attr("__value");
+
+          Boxed_Value result;
+          if (m_base_oper != Operators::Opers::invalid
+              && lhs_val.get_type_info().is_arithmetic()
+              && rhs_val.get_type_info().is_arithmetic()) {
+            result = Boxed_Number::do_oper(m_base_oper, lhs_val, rhs_val);
+          } else {
+            std::array<Boxed_Value, 2> underlying_params{lhs_val, rhs_val};
+            result = m_engine.call_function(m_base_op_name, m_loc, Function_Params(underlying_params), t_conversions);
+          }
+
+          lhs.get_attr("__value") = result;
+          return params[0];
+        }
+
+      private:
+        bool type_matches(const Boxed_Value &bv, const Type_Conversions_State &t_conversions) const noexcept {
+          if (!bv.get_type_info().bare_equal(user_type<dispatch::Dynamic_Object>())) {
+            return false;
+          }
+          try {
+            const auto &d = boxed_cast<const dispatch::Dynamic_Object &>(bv, &t_conversions);
+            return d.get_type_name() == m_type_name;
+          } catch (...) {
+            return false;
+          }
+        }
+
+        std::string m_type_name;
+        std::string m_op_name;
+        Operators::Opers m_base_oper;
+        std::string m_base_op_name;
+        chaiscript::detail::Dispatch_Engine &m_engine;
+        mutable std::atomic_uint_fast32_t m_loc{0};
+      };
+
     } // namespace detail
 
     template<typename T>
@@ -225,11 +389,11 @@ namespace chaiscript {
 
       // static and public so we can use this to process Switch_AST_Node case equality
       static Boxed_Value do_oper(const chaiscript::detail::Dispatch_State &t_ss,
-                          Operators::Opers t_oper,
-                          const std::string &t_oper_string,
-                          const Boxed_Value &t_lhs,
-                          const Boxed_Value &t_rhs,
-                          std::atomic_uint_fast32_t &t_loc) {
+                                 Operators::Opers t_oper,
+                                 const std::string &t_oper_string,
+                                 const Boxed_Value &t_lhs,
+                                 const Boxed_Value &t_rhs,
+                                 std::atomic_uint_fast32_t &t_loc) {
         try {
           if (t_oper != Operators::Opers::invalid && t_lhs.get_type_info().is_arithmetic() && t_rhs.get_type_info().is_arithmetic()) {
             // If it's an arithmetic operation we want to short circuit dispatch
@@ -438,6 +602,8 @@ namespace chaiscript {
         if (m_oper != Operators::Opers::invalid && params[0].get_type_info().is_arithmetic() && params[1].get_type_info().is_arithmetic()) {
           try {
             return Boxed_Number::do_oper(m_oper, params[0], params[1]);
+          } catch (const chaiscript::exception::arithmetic_error &) {
+            throw;
           } catch (const std::exception &) {
             throw exception::eval_error("Error with unsupported arithmetic assignment operation.");
           }
@@ -786,40 +952,43 @@ namespace chaiscript {
         return false;
       }
 
-      Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &t_ss) const override {
+      static std::shared_ptr<dispatch::Proxy_Function_Base> make_proxy_function(
+          const Def_AST_Node<T> &t_node, const chaiscript::detail::Dispatch_State &t_ss) {
         std::vector<std::string> t_param_names;
         size_t numparams = 0;
 
         dispatch::Param_Types param_types;
 
-        if ((this->children.size() > 1) && (this->children[1]->identifier == AST_Node_Type::Arg_List)) {
-          numparams = this->children[1]->children.size();
-          t_param_names = Arg_List_AST_Node<T>::get_arg_names(*this->children[1]);
-          param_types = Arg_List_AST_Node<T>::get_arg_types(*this->children[1], t_ss);
+        if ((t_node.children.size() > 1) && (t_node.children[1]->identifier == AST_Node_Type::Arg_List)) {
+          numparams = t_node.children[1]->children.size();
+          t_param_names = Arg_List_AST_Node<T>::get_arg_names(*t_node.children[1]);
+          param_types = Arg_List_AST_Node<T>::get_arg_types(*t_node.children[1], t_ss);
         }
 
         std::reference_wrapper<chaiscript::detail::Dispatch_Engine> engine(*t_ss);
         std::shared_ptr<dispatch::Proxy_Function_Base> guard;
-        if (m_guard_node) {
+        if (t_node.m_guard_node) {
           guard = dispatch::make_dynamic_proxy_function(
-              [engine, guardnode = m_guard_node, t_param_names](const Function_Params &t_params) {
+              [engine, guardnode = t_node.m_guard_node, t_param_names](const Function_Params &t_params) {
                 return detail::eval_function(engine, *guardnode, t_param_names, t_params);
               },
               static_cast<int>(numparams),
-              m_guard_node);
+              t_node.m_guard_node);
         }
 
+        return dispatch::make_dynamic_proxy_function(
+            [engine, func_node = t_node.m_body_node, t_param_names](const Function_Params &t_params) {
+              return detail::eval_function(engine, *func_node, t_param_names, t_params);
+            },
+            static_cast<int>(numparams),
+            t_node.m_body_node,
+            param_types,
+            guard);
+      }
+
+      Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &t_ss) const override {
         try {
-          const std::string &l_function_name = this->children[0]->text;
-          t_ss->add(dispatch::make_dynamic_proxy_function(
-                        [engine, func_node = m_body_node, t_param_names](const Function_Params &t_params) {
-                          return detail::eval_function(engine, *func_node, t_param_names, t_params);
-                        },
-                        static_cast<int>(numparams),
-                        m_body_node,
-                        param_types,
-                        guard),
-                    l_function_name);
+          t_ss->add(make_proxy_function(*this, t_ss), this->children[0]->text);
         } catch (const exception::name_conflict_error &e) {
           throw exception::eval_error("Function redefined '" + e.name() + "'");
         }
@@ -885,6 +1054,268 @@ namespace chaiscript {
       }
     };
 
+    template<typename T>
+    struct Using_AST_Node final : AST_Node_Impl<T> {
+      Using_AST_Node(std::string t_ast_node_text, Parse_Location t_loc, std::vector<AST_Node_Impl_Ptr<T>> t_children)
+          : AST_Node_Impl<T>(std::move(t_ast_node_text), AST_Node_Type::Using, std::move(t_loc), std::move(t_children)) {
+        assert(this->children.size() == 2);
+      }
+
+      Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &t_ss) const override {
+        const auto &new_type_name = this->children[0]->text;
+        const auto &base_type_name = this->children[1]->text;
+
+        const auto base_type = t_ss->get_type(base_type_name, true);
+
+        t_ss->add(user_type<dispatch::Dynamic_Object>(), new_type_name);
+
+        dispatch::Param_Types param_types(std::vector<std::pair<std::string, Type_Info>>{
+            {new_type_name, Type_Info()},
+            {base_type_name, base_type}});
+
+        auto ctor_body = dispatch::make_dynamic_proxy_function(
+            [](const Function_Params &t_params) -> Boxed_Value {
+              auto *obj = static_cast<dispatch::Dynamic_Object *>(t_params[0].get_ptr());
+              obj->get_attr("__value") = t_params[1];
+              return void_var();
+            },
+            2,
+            std::shared_ptr<AST_Node>(),
+            param_types);
+
+        try {
+          t_ss->add(std::make_shared<dispatch::detail::Dynamic_Object_Constructor>(new_type_name, ctor_body), new_type_name);
+        } catch (const exception::name_conflict_error &e) {
+          throw exception::eval_error("Type alias redefined '" + e.name() + "'");
+        }
+
+        dispatch::Param_Types to_underlying_param_types(std::vector<std::pair<std::string, Type_Info>>{
+            {new_type_name, user_type<dispatch::Dynamic_Object>()}});
+
+        auto to_underlying_body = dispatch::make_dynamic_proxy_function(
+            [](const Function_Params &t_params) -> Boxed_Value {
+              const auto *obj = static_cast<const dispatch::Dynamic_Object *>(t_params[0].get_const_ptr());
+              return obj->get_attr("__value");
+            },
+            1,
+            std::shared_ptr<AST_Node>(),
+            to_underlying_param_types);
+
+        t_ss->add(to_underlying_body, "to_underlying");
+
+        auto &engine = *t_ss;
+
+        struct Op_Entry {
+          const char *name;
+          Operators::Opers oper;
+          bool rewrap;
+        };
+
+        static constexpr Op_Entry ops[] = {
+            {"+", Operators::Opers::sum, true},
+            {"-", Operators::Opers::difference, true},
+            {"*", Operators::Opers::product, true},
+            {"/", Operators::Opers::quotient, true},
+            {"%", Operators::Opers::remainder, true},
+            {"<<", Operators::Opers::shift_left, true},
+            {">>", Operators::Opers::shift_right, true},
+            {"&", Operators::Opers::bitwise_and, true},
+            {"|", Operators::Opers::bitwise_or, true},
+            {"^", Operators::Opers::bitwise_xor, true},
+            {"<", Operators::Opers::less_than, false},
+            {">", Operators::Opers::greater_than, false},
+            {"<=", Operators::Opers::less_than_equal, false},
+            {">=", Operators::Opers::greater_than_equal, false},
+            {"==", Operators::Opers::equals, false},
+            {"!=", Operators::Opers::not_equal, false},
+        };
+
+        for (const auto &op : ops) {
+          t_ss->add(
+              chaiscript::make_shared<dispatch::Proxy_Function_Base, detail::Strong_Typedef_Binary_Op>(
+                  new_type_name, std::string(op.name), op.oper, op.rewrap, engine),
+              op.name);
+        }
+
+        struct Compound_Op_Entry {
+          const char *name;
+          Operators::Opers base_oper;
+          const char *base_op_name;
+        };
+
+        static constexpr Compound_Op_Entry compound_ops[] = {
+            {"+=", Operators::Opers::sum, "+"},
+            {"-=", Operators::Opers::difference, "-"},
+            {"*=", Operators::Opers::product, "*"},
+            {"/=", Operators::Opers::quotient, "/"},
+            {"%=", Operators::Opers::remainder, "%"},
+            {"<<=", Operators::Opers::shift_left, "<<"},
+            {">>=", Operators::Opers::shift_right, ">>"},
+            {"&=", Operators::Opers::bitwise_and, "&"},
+            {"|=", Operators::Opers::bitwise_or, "|"},
+            {"^=", Operators::Opers::bitwise_xor, "^"},
+        };
+
+        for (const auto &op : compound_ops) {
+          t_ss->add(
+              chaiscript::make_shared<dispatch::Proxy_Function_Base, detail::Strong_Typedef_Compound_Assign_Op>(
+                  new_type_name, std::string(op.name), op.base_oper, std::string(op.base_op_name), engine),
+              op.name);
+        }
+
+        return void_var();
+      }
+    };
+
+    template<typename T>
+    struct Enum_AST_Node final : AST_Node_Impl<T> {
+      Enum_AST_Node(std::string t_ast_node_text, Parse_Location t_loc, std::vector<AST_Node_Impl_Ptr<T>> t_children)
+          : AST_Node_Impl<T>(std::move(t_ast_node_text), AST_Node_Type::Enum, std::move(t_loc), std::move(t_children)) {
+      }
+
+      Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &t_ss) const override {
+        const auto &enum_name = this->children[0]->text;
+        const auto &underlying_type_name = this->children[1]->text;
+        const auto underlying_ti = t_ss->get_type(underlying_type_name);
+
+        dispatch::Dynamic_Object container(enum_name);
+        std::vector<Boxed_Value> valid_values;
+
+        for (size_t i = 2; i < this->children.size(); i += 2) {
+          const auto &val_name = this->children[i]->text;
+          const auto val_bv = Boxed_Number(this->children[i + 1]->eval(t_ss)).get_as(underlying_ti).bv;
+          valid_values.push_back(val_bv);
+
+          dispatch::Dynamic_Object dobj(enum_name);
+          dobj.get_attr("value") = val_bv;
+          dobj.set_explicit(true);
+          container[val_name] = const_var(dobj);
+        }
+
+        auto shared_valid = std::make_shared<const std::vector<Boxed_Value>>(std::move(valid_values));
+
+        container[enum_name] = var(
+            fun([shared_valid, enum_name, underlying_ti](const Boxed_Number &t_val) -> Boxed_Value {
+              const auto converted = t_val.get_as(underlying_ti);
+              for (const auto &v : *shared_valid) {
+                if (Boxed_Number::equals(Boxed_Number(v), converted)) {
+                  dispatch::Dynamic_Object dobj(enum_name);
+                  dobj.get_attr("value") = converted.bv;
+                  dobj.set_explicit(true);
+                  return const_var(dobj);
+                }
+              }
+              throw exception::eval_error("Value is not valid for enum '" + enum_name + "'");
+            }));
+
+        t_ss->add_global_const(const_var(container), enum_name);
+
+        t_ss->add(
+            std::make_shared<dispatch::detail::Dynamic_Object_Function>(
+                enum_name,
+                fun([](const dispatch::Dynamic_Object &lhs, const dispatch::Dynamic_Object &rhs) {
+                  return Boxed_Number::equals(Boxed_Number(lhs.get_attr("value")), Boxed_Number(rhs.get_attr("value")));
+                })),
+            "==");
+
+        t_ss->add(
+            std::make_shared<dispatch::detail::Dynamic_Object_Function>(
+                enum_name,
+                fun([](const dispatch::Dynamic_Object &lhs, const dispatch::Dynamic_Object &rhs) {
+                  return !Boxed_Number::equals(Boxed_Number(lhs.get_attr("value")), Boxed_Number(rhs.get_attr("value")));
+                })),
+            "!=");
+
+        t_ss->add(
+            std::make_shared<dispatch::detail::Dynamic_Object_Function>(
+                enum_name,
+                fun([](const dispatch::Dynamic_Object &obj) { return obj.get_attr("value"); })),
+            "to_underlying");
+
+        return void_var();
+      }
+    };
+
+    template<typename T>
+    struct Namespace_Block_AST_Node final : AST_Node_Impl<T> {
+      Namespace_Block_AST_Node(std::string t_ast_node_text, Parse_Location t_loc, std::vector<AST_Node_Impl_Ptr<T>> t_children)
+          : AST_Node_Impl<T>(std::move(t_ast_node_text), AST_Node_Type::Namespace_Block, std::move(t_loc), std::move(t_children)) {
+      }
+
+      Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &t_ss) const override {
+        const auto &ns_name = this->children[0]->text;
+
+        auto ns_name_bv = const_var(ns_name);
+        t_ss->call_function("namespace", m_ns_loc, Function_Params{&ns_name_bv, 1}, t_ss.conversions());
+
+        std::vector<std::string> parts;
+        {
+          std::string::size_type start = 0;
+          std::string::size_type pos = 0;
+          while ((pos = ns_name.find("::", start)) != std::string::npos) {
+            parts.push_back(ns_name.substr(start, pos - start));
+            start = pos + 2;
+          }
+          parts.push_back(ns_name.substr(start));
+        }
+
+        Boxed_Value ns_bv = t_ss.get_object(parts[0], m_root_loc);
+
+        for (size_t i = 1; i < parts.size(); ++i) {
+          auto &parent_ns = boxed_cast<dispatch::Dynamic_Object &>(ns_bv);
+          ns_bv = parent_ns.get_attr(parts[i]);
+        }
+
+        auto &target_ns = boxed_cast<dispatch::Dynamic_Object &>(ns_bv);
+
+        const auto process_statement = [&](const AST_Node_Impl<T> &stmt) {
+          if (stmt.identifier == AST_Node_Type::Def) {
+            const auto &def_node = static_cast<const Def_AST_Node<T> &>(stmt);
+            target_ns[def_node.children[0]->text] = Boxed_Value(Def_AST_Node<T>::make_proxy_function(def_node, t_ss));
+          } else if (stmt.identifier == AST_Node_Type::Assign_Decl
+                     || stmt.identifier == AST_Node_Type::Const_Assign_Decl) {
+            const auto &var_name = stmt.children[0]->text;
+            auto value = detail::clone_if_necessary(stmt.children[1]->eval(t_ss), m_clone_loc, t_ss);
+            value.reset_return_value();
+            if (stmt.identifier == AST_Node_Type::Const_Assign_Decl) {
+              value.make_const();
+            }
+            target_ns[var_name] = std::move(value);
+          } else if (stmt.identifier == AST_Node_Type::Equation
+                     && !stmt.children.empty()
+                     && (stmt.children[0]->identifier == AST_Node_Type::Var_Decl
+                         || stmt.children[0]->identifier == AST_Node_Type::Const_Var_Decl)) {
+            const auto &var_name = stmt.children[0]->children[0]->text;
+            auto value = detail::clone_if_necessary(stmt.children[1]->eval(t_ss), m_clone_loc, t_ss);
+            value.reset_return_value();
+            target_ns[var_name] = std::move(value);
+          } else if (stmt.identifier == AST_Node_Type::Var_Decl) {
+            const auto &var_name = stmt.children[0]->text;
+            target_ns[var_name] = Boxed_Value();
+          } else {
+            throw exception::eval_error("Only declarations (def, var, auto, global) are allowed inside namespace blocks");
+          }
+        };
+
+        const auto &body = this->children[1];
+        if (body->identifier == AST_Node_Type::Block
+            || body->identifier == AST_Node_Type::Scopeless_Block) {
+          for (const auto &child : body->children) {
+            process_statement(*child);
+          }
+        } else {
+          process_statement(*body);
+        }
+
+        return void_var();
+      }
+
+    private:
+      mutable std::atomic_uint_fast32_t m_ns_loc = {0};
+      mutable std::atomic_uint_fast32_t m_root_loc = {0};
+      mutable std::atomic_uint_fast32_t m_clone_loc = {0};
+    };
+
     template<typename T>
     struct If_AST_Node final : AST_Node_Impl<T> {
       If_AST_Node(std::string t_ast_node_text, Parse_Location t_loc, std::vector<AST_Node_Impl_Ptr<T>> t_children)
@@ -919,7 +1350,7 @@ namespace chaiscript {
         };
 
         const auto call_function = [&t_ss](const auto &t_funcs, const Boxed_Value &t_param) {
-          return dispatch::dispatch(*t_funcs, Function_Params{t_param}, t_ss.conversions());
+          return dispatch::dispatch(*t_funcs, Function_Params{&t_param, 1}, t_ss.conversions());
         };
 
         const std::string &loop_var_name = this->children[0]->text;
@@ -1215,8 +1646,8 @@ namespace chaiscript {
             return Boxed_Number::do_oper(m_oper, bv);
           } else {
             chaiscript::eval::detail::Function_Push_Pop fpp(t_ss);
-            fpp.save_params(Function_Params{bv});
-            return t_ss->call_function(this->text, m_loc, Function_Params{bv}, t_ss.conversions());
+            fpp.save_params(Function_Params{&bv, 1});
+            return t_ss->call_function(this->text, m_loc, Function_Params{&bv, 1}, t_ss.conversions());
           }
         } catch (const exception::dispatch_error &e) {
           throw exception::eval_error("Error with prefix operator evaluation: '" + this->text + "'", e.parameters, e.functions, false, *t_ss);
@@ -1303,6 +1734,7 @@ namespace chaiscript {
 
       Boxed_Value handle_exception(const chaiscript::detail::Dispatch_State &t_ss, const Boxed_Value &t_except) const {
         Boxed_Value retval;
+        bool handled = false;
 
         size_t end_point = this->children.size();
         if (this->children.back()->identifier == AST_Node_Type::Finally) {
@@ -1316,30 +1748,33 @@ namespace chaiscript {
           if (catch_block.children.size() == 1) {
             // No variable capture
             retval = catch_block.children[0]->eval(t_ss);
+            handled = true;
             break;
           } else if (catch_block.children.size() == 2 || catch_block.children.size() == 3) {
             const auto name = Arg_List_AST_Node<T>::get_arg_name(*catch_block.children[0]);
 
             if (dispatch::Param_Types(
                     std::vector<std::pair<std::string, Type_Info>>{Arg_List_AST_Node<T>::get_arg_type(*catch_block.children[0], t_ss)})
-                    .match(Function_Params{t_except}, t_ss.conversions())
+                    .match(Function_Params{&t_except, 1}, t_ss.conversions())
                     .first) {
               t_ss.add_object(name, t_except);
 
               if (catch_block.children.size() == 2) {
                 // Variable capture
                 retval = catch_block.children[1]->eval(t_ss);
+                handled = true;
                 break;
               }
             }
           } else {
-            if (this->children.back()->identifier == AST_Node_Type::Finally) {
-              this->children.back()->children[0]->eval(t_ss);
-            }
             throw exception::eval_error("Internal error: catch block size unrecognized");
           }
         }
 
+        if (!handled) {
+          throw;
+        }
+
         return retval;
       }
 
@@ -1349,17 +1784,19 @@ namespace chaiscript {
         chaiscript::eval::detail::Scope_Push_Pop spp(t_ss);
 
         try {
-          retval = this->children[0]->eval(t_ss);
-        } catch (const exception::eval_error &e) {
-          retval = handle_exception(t_ss, Boxed_Value(std::ref(e)));
-        } catch (const std::runtime_error &e) {
-          retval = handle_exception(t_ss, Boxed_Value(std::ref(e)));
-        } catch (const std::out_of_range &e) {
-          retval = handle_exception(t_ss, Boxed_Value(std::ref(e)));
-        } catch (const std::exception &e) {
-          retval = handle_exception(t_ss, Boxed_Value(std::ref(e)));
-        } catch (Boxed_Value &e) {
-          retval = handle_exception(t_ss, e);
+          try {
+            retval = this->children[0]->eval(t_ss);
+          } catch (const exception::eval_error &e) {
+            retval = handle_exception(t_ss, Boxed_Value(std::ref(e)));
+          } catch (const std::runtime_error &e) {
+            retval = handle_exception(t_ss, Boxed_Value(std::ref(e)));
+          } catch (const std::out_of_range &e) {
+            retval = handle_exception(t_ss, Boxed_Value(std::ref(e)));
+          } catch (const std::exception &e) {
+            retval = handle_exception(t_ss, Boxed_Value(std::ref(e)));
+          } catch (Boxed_Value &e) {
+            retval = handle_exception(t_ss, e);
+          }
         } catch (...) {
           if (this->children.back()->identifier == AST_Node_Type::Finally) {
             this->children.back()->children[0]->eval(t_ss);

include/chaiscript/language/chaiscript_optimizer.hpp

@@ -397,8 +397,9 @@ namespace chaiscript {
                                         assert(children.size() == 1);
                                         chaiscript::eval::detail::Scope_Push_Pop spp(t_ss);
 
-                                        int i = start_int;
-                                        t_ss.add_object(id, var(&i));
+                                        Boxed_Value bv_i(start_int);
+                                        auto &i = *static_cast<int *>(bv_i.get_ptr());
+                                        t_ss.add_object(id, bv_i);
 
                                         try {
                                           for (; i < end_int; ++i) {

include/chaiscript/language/chaiscript_parser.hpp

@@ -14,6 +14,7 @@
 #include <cstring>
 #include <exception>
 #include <iostream>
+#include <iterator>
 #include <memory>
 #include <sstream>
 #include <string>
@@ -22,15 +23,11 @@
 #include "../dispatchkit/boxed_value.hpp"
 #include "../utility/hash.hpp"
 #include "../utility/static_string.hpp"
+#include "../utility/unicode.hpp"
 #include "chaiscript_common.hpp"
 #include "chaiscript_optimizer.hpp"
 #include "chaiscript_tracer.hpp"
 
-#if defined(CHAISCRIPT_UTF16_UTF32)
-#include <codecvt>
-#include <locale>
-#endif
-
 #if defined(CHAISCRIPT_MSVC) && defined(max) && defined(min)
 #define CHAISCRIPT_PUSHED_MIN_MAX
 #pragma push_macro("max") // Why Microsoft? why? This is worse than bad
@@ -64,41 +61,26 @@ namespace chaiscript {
       // Generic for u16, u32 and wchar
       template<typename string_type>
       struct Char_Parser_Helper {
-        // common for all implementations
-        static std::string u8str_from_ll(long long val) {
-          using char_type = std::string::value_type;
-
-          char_type c[2];
-          c[1] = char_type(val);
-          c[0] = char_type(val >> 8);
-
-          if (c[0] == 0) {
-            return std::string(1, c[1]); // size, character
-          }
-
-          return std::string(c, 2); // char buffer, size
-        }
-
         static string_type str_from_ll(long long val) {
-          using target_char_type = typename string_type::value_type;
-#if defined(CHAISCRIPT_UTF16_UTF32)
-          // prepare converter
-          std::wstring_convert<std::codecvt_utf8<target_char_type>, target_char_type> converter;
-          // convert
-          return converter.from_bytes(u8str_from_ll(val));
-#else
-          // no conversion available, just put value as character
-          return string_type(1, target_char_type(val)); // size, character
-#endif
+          string_type out;
+          utility::unicode::append_codepoint(out, static_cast<std::uint32_t>(val));
+          return out;
         }
       };
 
-      // Specialization for char AKA UTF-8
+      // Specialization for char AKA UTF-8: preserve raw two-byte packing
+      // of multi-character literals.
       template<>
       struct Char_Parser_Helper<std::string> {
         static std::string str_from_ll(long long val) {
-          // little SFINAE trick to avoid base class
-          return Char_Parser_Helper<std::true_type>::u8str_from_ll(val);
+          using char_type = std::string::value_type;
+          char_type c[2];
+          c[1] = char_type(val);
+          c[0] = char_type(val >> 8);
+          if (c[0] == 0) {
+            return std::string(1, c[1]);
+          }
+          return std::string(c, 2);
         }
       };
     } // namespace detail
@@ -128,9 +110,7 @@ namespace chaiscript {
 
       template<typename Array2D, typename First, typename Second>
       constexpr static void set_alphabet(Array2D &array, const First first, const Second second) noexcept {
-        auto *first_ptr = &std::get<0>(array) + static_cast<std::size_t>(first);
-        auto *second_ptr = &std::get<0>(*first_ptr) + static_cast<std::size_t>(second);
-        *second_ptr = true;
+        array[static_cast<std::size_t>(first)][static_cast<std::size_t>(second)] = true;
       }
 
       constexpr static std::array<std::array<bool, detail::lengthof_alphabet>, detail::max_alphabet> build_alphabet() noexcept {
@@ -360,13 +340,13 @@ namespace chaiscript {
               ++col;
             }
 
-            ++m_pos;
+            std::advance(m_pos, 1);
           }
           return *this;
         }
 
         constexpr Position &operator--() noexcept {
-          --m_pos;
+          std::advance(m_pos, -1);
           if (*m_pos == '\n') {
             --line;
             col = m_last_col;
@@ -377,7 +357,7 @@ namespace chaiscript {
         }
 
         constexpr Position &operator+=(size_t t_distance) noexcept {
-          *this = (*this) + t_distance;
+          *this = *this + t_distance;
           return *this;
         }
 
@@ -406,9 +386,9 @@ namespace chaiscript {
 
         constexpr bool operator!=(const Position &t_rhs) const noexcept { return m_pos != t_rhs.m_pos; }
 
-        constexpr bool has_more() const noexcept { return m_pos != m_end; }
+        [[nodiscard]] constexpr bool has_more() const noexcept { return m_pos != m_end; }
 
-        constexpr size_t remaining() const noexcept { return static_cast<size_t>(m_end - m_pos); }
+        [[nodiscard]] constexpr size_t remaining() const noexcept { return static_cast<size_t>(m_end - m_pos); }
 
         constexpr const char &operator*() const noexcept {
           if (m_pos == m_end) {
@@ -458,7 +438,7 @@ namespace chaiscript {
       constexpr static Operator_Matches m_operator_matches{};
 
       /// test a char in an m_alphabet
-      constexpr bool char_in_alphabet(char c, detail::Alphabet a) const noexcept { return m_alphabet[a][static_cast<uint8_t>(c)]; }
+      [[nodiscard]] constexpr bool char_in_alphabet(char c, detail::Alphabet a) const noexcept { return m_alphabet[a][static_cast<uint8_t>(c)]; }
 
       /// Prints the parsed ast_nodes as a tree
       void debug_print(const AST_Node &t, std::string prepend = "") const override {
@@ -509,7 +489,7 @@ namespace chaiscript {
         if (m_position.remaining() >= len) {
           const char *file_pos = &(*m_position);
           for (size_t pos = 0; pos < len; ++pos) {
-            if (sym.c_str()[pos] != file_pos[pos]) {
+            if (sym[pos] != *std::next(file_pos, static_cast<std::ptrdiff_t>(pos))) {
               return false;
             }
           }
@@ -530,20 +510,9 @@ namespace chaiscript {
             }
           }
           return true;
-        } else if (Symbol_(m_singleline_comment)) {
-          while (m_position.has_more()) {
-            if (Symbol_(m_cr_lf)) {
-              m_position -= 2;
-              break;
-            } else if (Char_('\n')) {
-              --m_position;
-              break;
-            } else {
-              ++m_position;
-            }
-          }
-          return true;
-        } else if (Symbol_(m_annotation)) {
+        }
+
+        if (Symbol_(m_singleline_comment) || Symbol_(m_annotation)) {
           while (m_position.has_more()) {
             if (Symbol_(m_cr_lf)) {
               m_position -= 2;
@@ -1060,7 +1029,7 @@ namespace chaiscript {
       template<typename string_type>
       struct Char_Parser {
         string_type &match;
-        using char_type = typename string_type::value_type;
+        using char_type = string_type::value_type;
         bool is_escaped = false;
         bool is_interpolated = false;
         bool saw_interpolation_marker = false;
@@ -1119,40 +1088,20 @@ namespace chaiscript {
         }
 
         void process_unicode() {
-          const auto ch = static_cast<uint32_t>(std::stoi(hex_matches, nullptr, 16));
+          const auto ch = static_cast<std::uint32_t>(std::stoi(hex_matches, nullptr, 16));
           const auto match_size = hex_matches.size();
           hex_matches.clear();
           is_escaped = false;
           const auto u_size = unicode_size;
           unicode_size = 0;
 
-          char buf[4];
           if (u_size != match_size) {
             throw exception::eval_error("Incomplete unicode escape sequence");
           }
-          if (u_size == 4 && ch >= 0xD800 && ch <= 0xDFFF) {
+          if (u_size == 4 && utility::unicode::is_surrogate(ch)) {
             throw exception::eval_error("Invalid 16 bit universal character");
           }
-
-          if (ch < 0x80) {
-            match += static_cast<char>(ch);
-          } else if (ch < 0x800) {
-            buf[0] = static_cast<char>(0xC0 | (ch >> 6));
-            buf[1] = static_cast<char>(0x80 | (ch & 0x3F));
-            match.append(buf, 2);
-          } else if (ch < 0x10000) {
-            buf[0] = static_cast<char>(0xE0 | (ch >> 12));
-            buf[1] = static_cast<char>(0x80 | ((ch >> 6) & 0x3F));
-            buf[2] = static_cast<char>(0x80 | (ch & 0x3F));
-            match.append(buf, 3);
-          } else if (ch < 0x200000) {
-            buf[0] = static_cast<char>(0xF0 | (ch >> 18));
-            buf[1] = static_cast<char>(0x80 | ((ch >> 12) & 0x3F));
-            buf[2] = static_cast<char>(0x80 | ((ch >> 6) & 0x3F));
-            buf[3] = static_cast<char>(0x80 | (ch & 0x3F));
-            match.append(buf, 4);
-          } else {
-            // this must be an invalid escape sequence?
+          if (utility::unicode::append_utf8(match, ch) == 0) {
             throw exception::eval_error("Invalid 32 bit universal character");
           }
         }
@@ -1548,7 +1497,7 @@ namespace chaiscript {
         if (m_position.remaining() >= len) {
           auto tmp = m_position;
           for (size_t i = 0; tmp.has_more() && i < len; ++i) {
-            if (*tmp != t_s.c_str()[i]) {
+            if (*tmp != t_s[i]) {
               return false;
             }
             ++tmp;
@@ -1575,7 +1524,7 @@ namespace chaiscript {
         return retval;
       }
 
-      bool is_operator(std::string_view t_s) const noexcept { return m_operator_matches.is_match(t_s); }
+      [[nodiscard]] bool is_operator(std::string_view t_s) const noexcept { return m_operator_matches.is_match(t_s); }
 
       /// Reads (and potentially captures) a symbol group from input if it matches the parameter
       bool Symbol(const utility::Static_String &t_s, const bool t_disallow_prevention = false) {
@@ -1990,6 +1939,44 @@ namespace chaiscript {
       }
 
       /// Reads a class block from input
+      bool Namespace_Block() {
+        Depth_Counter dc{this};
+        const auto prev_stack_top = m_match_stack.size();
+        const auto prev_pos = m_position;
+
+        if (Keyword("namespace")) {
+          if (Id(true)) {
+            std::string ns_name = m_match_stack.back()->text;
+
+            while (Symbol("::")) {
+              if (!Id(true)) {
+                throw exception::eval_error("Incomplete namespace name after '::'",
+                                            File_Position(m_position.line, m_position.col),
+                                            *m_filename);
+              }
+              ns_name += "::" + m_match_stack.back()->text;
+              m_match_stack.pop_back();
+            }
+
+            m_match_stack.back() = make_node<eval::Id_AST_Node<Tracer>>(ns_name, prev_pos.line, prev_pos.col);
+
+            while (Eol()) {
+            }
+
+            if (Block()) {
+              build_match<eval::Namespace_Block_AST_Node<Tracer>>(prev_stack_top);
+              return true;
+            }
+          }
+
+          m_position = prev_pos;
+          while (prev_stack_top != m_match_stack.size()) {
+            m_match_stack.pop_back();
+          }
+        }
+        return false;
+      }
+
       bool Class(const bool t_class_allowed) {
         Depth_Counter dc{this};
         bool retval = false;
@@ -2031,6 +2018,134 @@ namespace chaiscript {
         return retval;
       }
 
+      bool Using(const bool t_class_allowed) {
+        Depth_Counter dc{this};
+
+        const auto prev_stack_top = m_match_stack.size();
+
+        if (Keyword("using")) {
+          if (!t_class_allowed) {
+            throw exception::eval_error("Type alias definitions only allowed at top scope",
+                                        File_Position(m_position.line, m_position.col),
+                                        *m_filename);
+          }
+
+          if (!Id(true)) {
+            throw exception::eval_error("Missing type name in 'using' declaration",
+                                        File_Position(m_position.line, m_position.col),
+                                        *m_filename);
+          }
+
+          if (!Symbol("=", true)) {
+            throw exception::eval_error("Missing '=' in 'using' declaration",
+                                        File_Position(m_position.line, m_position.col),
+                                        *m_filename);
+          }
+
+          if (!Id(true)) {
+            throw exception::eval_error("Missing base type name in 'using' declaration",
+                                        File_Position(m_position.line, m_position.col),
+                                        *m_filename);
+          }
+
+          build_match<eval::Using_AST_Node<Tracer>>(prev_stack_top);
+          return true;
+        }
+
+        return false;
+      }
+
+      bool Enum(const bool t_allowed) {
+        Depth_Counter dc{this};
+        bool retval = false;
+
+        const auto prev_stack_top = m_match_stack.size();
+
+        if (Keyword("enum")) {
+          if (!Keyword("class") && !Keyword("struct")) {
+            throw exception::eval_error("Expected 'class' or 'struct' after 'enum' (only 'enum class'/'enum struct' is supported)",
+                                        File_Position(m_position.line, m_position.col),
+                                        *m_filename);
+          }
+
+          if (!t_allowed) {
+            throw exception::eval_error("Enum definitions only allowed at top scope",
+                                        File_Position(m_position.line, m_position.col),
+                                        *m_filename);
+          }
+
+          retval = true;
+
+          if (!Id(true)) {
+            throw exception::eval_error("Missing enum class name in definition", File_Position(m_position.line, m_position.col), *m_filename);
+          }
+
+          std::string underlying_type = "int";
+          if (Char(':')) {
+            if (!Id(false)) {
+              throw exception::eval_error("Expected underlying type after ':'",
+                                          File_Position(m_position.line, m_position.col),
+                                          *m_filename);
+            }
+            underlying_type = m_match_stack.back()->text;
+            m_match_stack.pop_back();
+          }
+
+          m_match_stack.push_back(
+              make_node<eval::Constant_AST_Node<Tracer>>(underlying_type, m_position.line, m_position.col, const_var(underlying_type)));
+
+          if (!Char('{')) {
+            throw exception::eval_error("Expected '{' after enum class declaration", File_Position(m_position.line, m_position.col), *m_filename);
+          }
+
+          int next_value = 0;
+
+          while (Eol()) {
+          }
+
+          if (!Char('}')) {
+            do {
+              while (Eol()) {
+              }
+
+              if (!Id(true)) {
+                throw exception::eval_error("Expected enum value name", File_Position(m_position.line, m_position.col), *m_filename);
+              }
+
+              if (Symbol("=")) {
+                if (!Num()) {
+                  throw exception::eval_error("Expected integer after '=' in enum definition",
+                                              File_Position(m_position.line, m_position.col),
+                                              *m_filename);
+                }
+                next_value = static_cast<int>(std::stoi(m_match_stack.back()->text));
+                m_match_stack.pop_back();
+              }
+
+              m_match_stack.push_back(
+                  make_node<eval::Constant_AST_Node<Tracer>>(std::to_string(next_value), m_position.line, m_position.col, const_var(next_value)));
+              ++next_value;
+
+              while (Eol()) {
+              }
+            } while (Char(',') && !Char('}'));
+
+            while (Eol()) {
+            }
+
+            if (!Char('}')) {
+              throw exception::eval_error("Expected '}' to close enum class definition",
+                                          File_Position(m_position.line, m_position.col),
+                                          *m_filename);
+            }
+          }
+
+          build_match<eval::Enum_AST_Node<Tracer>>(prev_stack_top);
+        }
+
+        return retval;
+      }
+
       /// Reads a while block from input
       bool While() {
         Depth_Counter dc{this};
@@ -2282,7 +2397,7 @@ namespace chaiscript {
         const auto prev_stack_top = m_match_stack.size();
 
         if (Keyword("return")) {
-          Operator();
+          Equation();
           build_match<eval::Return_AST_Node<Tracer>>(prev_stack_top);
           return true;
         } else {
@@ -2379,7 +2494,7 @@ namespace chaiscript {
               }
 
               build_match<eval::Array_Call_AST_Node<Tracer>>(prev_stack_top);
-            } else if (Symbol(".")) {
+            } else if (Symbol(".") || Symbol("::")) {
               has_more = true;
               if (!(Id(true))) {
                 throw exception::eval_error("Incomplete dot access fun call", File_Position(m_position.line, m_position.col), *m_filename);
@@ -2583,7 +2698,7 @@ namespace chaiscript {
         bool retval = false;
         const auto prev_stack_top = m_match_stack.size();
 
-        if (m_operators[t_precedence] != Operator_Precedence::Prefix) {
+        if (t_precedence < m_operators.size() && m_operators[t_precedence] < Operator_Precedence::Prefix) {
           if (Operator(t_precedence + 1)) {
             retval = true;
             std::string oper;
@@ -2597,7 +2712,7 @@ namespace chaiscript {
               }
 
               switch (m_operators[t_precedence]) {
-                case (Operator_Precedence::Ternary_Cond):
+                case Operator_Precedence::Ternary_Cond:
                   if (Symbol(":")) {
                     if (!Operator(t_precedence + 1)) {
                       throw exception::eval_error("Incomplete '" + oper + "' expression",
@@ -2612,24 +2727,24 @@ namespace chaiscript {
                   }
                   break;
 
-                case (Operator_Precedence::Addition):
-                case (Operator_Precedence::Multiplication):
-                case (Operator_Precedence::Shift):
-                case (Operator_Precedence::Equality):
-                case (Operator_Precedence::Bitwise_And):
-                case (Operator_Precedence::Bitwise_Xor):
-                case (Operator_Precedence::Bitwise_Or):
-                case (Operator_Precedence::Comparison):
+                case Operator_Precedence::Addition:
+                case Operator_Precedence::Multiplication:
+                case Operator_Precedence::Shift:
+                case Operator_Precedence::Equality:
+                case Operator_Precedence::Bitwise_And:
+                case Operator_Precedence::Bitwise_Xor:
+                case Operator_Precedence::Bitwise_Or:
+                case Operator_Precedence::Comparison:
                   build_match<eval::Binary_Operator_AST_Node<Tracer>>(prev_stack_top, oper);
                   break;
 
-                case (Operator_Precedence::Logical_And):
+                case Operator_Precedence::Logical_And:
                   build_match<eval::Logical_And_AST_Node<Tracer>>(prev_stack_top, oper);
                   break;
-                case (Operator_Precedence::Logical_Or):
+                case Operator_Precedence::Logical_Or:
                   build_match<eval::Logical_Or_AST_Node<Tracer>>(prev_stack_top, oper);
                   break;
-                case (Operator_Precedence::Prefix):
+                case Operator_Precedence::Prefix:
                   assert(false); // cannot reach here because of if() statement at the top
                   break;
 
@@ -2776,7 +2891,7 @@ namespace chaiscript {
 
         while (has_more) {
           const auto start = m_position;
-          if (Def() || Try() || If() || While() || Class(t_class_allowed) || For() || Switch()) {
+          if (Def() || Try() || If() || While() || Namespace_Block() || Class(t_class_allowed) || Using(t_class_allowed) || Enum(t_class_allowed) || For() || Switch()) {
             if (!saw_eol) {
               throw exception::eval_error("Two function definitions missing line separator",
                                           File_Position(start.line, start.col),
@@ -2826,7 +2941,7 @@ namespace chaiscript {
       /// Parses the given input string, tagging parsed ast_nodes with the given m_filename.
       AST_NodePtr parse_internal(const std::string &t_input, std::string t_fname) {
         const auto begin = t_input.empty() ? nullptr : &t_input.front();
-        const auto end = begin == nullptr ? nullptr : begin + t_input.size();
+        const auto end = begin == nullptr ? nullptr : std::next(begin, std::ssize(t_input));
         m_position = Position(begin, end);
         m_filename = std::make_shared<std::string>(std::move(t_fname));
 

include/chaiscript/utility/hash.hpp

@@ -8,7 +8,9 @@
 #define CHAISCRIPT_UTILITY_FNV1A_HPP_
 
 #include "../chaiscript_defines.hpp"
+
 #include <cstdint>
+#include <iterator>
 
 namespace chaiscript {
   namespace utility {
@@ -28,7 +30,7 @@ namespace chaiscript {
 
         while (begin != end) {
           h = (h ^ (*begin)) * 0x01000193;
-          ++begin;
+          std::advance(begin, 1);
         }
         return h;
 
@@ -43,7 +45,7 @@ namespace chaiscript {
 
       template<size_t N>
       static constexpr std::uint32_t hash(const char (&str)[N]) noexcept {
-        return hash(std::begin(str), std::end(str) - 1);
+        return hash(std::begin(str), std::prev(std::end(str)));
       }
 
       static constexpr std::uint32_t hash(std::string_view sv) noexcept {
@@ -64,7 +66,7 @@ namespace chaiscript {
           hash += std::uint32_t(*begin);
           hash += hash << 10;
           hash ^= hash >> 6;
-          ++begin;
+          std::advance(begin, 1);
         }
 
         hash += hash << 3;

include/chaiscript/utility/json.hpp

@@ -7,6 +7,7 @@
 
 #include "../chaiscript_defines.hpp"
 #include "quick_flat_map.hpp"
+#include "unicode.hpp"
 #include <cctype>
 #include <cmath>
 #include <cstdint>
@@ -44,21 +45,17 @@ namespace chaiscript::json {
         = std::variant<std::nullptr_t, chaiscript::utility::QuickFlatMap<std::string, JSON>, std::vector<JSON>, std::string, double, std::int64_t, bool>;
 
     struct Internal {
-      Internal(std::nullptr_t)
-          : d(nullptr) {
-      }
-      Internal()
-          : d(nullptr) {
-      }
-      Internal(Class c)
+      explicit Internal(std::nullptr_t) {}
+      Internal() = default;
+      Internal(const Class c)
           : d(make_type(c)) {
       }
       template<typename T>
-      Internal(T t)
+      explicit Internal(T t)
           : d(std::move(t)) {
       }
 
-      static Data make_type(Class c) {
+      static Data make_type(const Class c) {
         switch (c) {
           case Class::Null:
             return nullptr;
@@ -84,7 +81,7 @@ namespace chaiscript::json {
         }
       }
 
-      Class type() const noexcept { return Class(d.index()); }
+      [[nodiscard]] Class type() const noexcept { return Class(d.index()); }
 
       template<auto ClassValue, typename Visitor, typename Or>
       decltype(auto) visit_or(Visitor &&visitor, Or &&other) const {
@@ -108,14 +105,14 @@ namespace chaiscript::json {
       auto &Float() { return get_set_type<Class::Floating>(); }
       auto &Bool() { return get_set_type<Class::Boolean>(); }
 
-      auto Map() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Object)>(&d); }
-      auto Vector() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Array)>(&d); }
-      auto String() const noexcept { return std::get_if<static_cast<std::size_t>(Class::String)>(&d); }
-      auto Int() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Integral)>(&d); }
-      auto Float() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Floating)>(&d); }
-      auto Bool() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Boolean)>(&d); }
+      [[nodiscard]] auto Map() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Object)>(&d); }
+      [[nodiscard]] auto Vector() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Array)>(&d); }
+      [[nodiscard]] auto String() const noexcept { return std::get_if<static_cast<std::size_t>(Class::String)>(&d); }
+      [[nodiscard]] auto Int() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Integral)>(&d); }
+      [[nodiscard]] auto Float() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Floating)>(&d); }
+      [[nodiscard]] auto Bool() const noexcept { return std::get_if<static_cast<std::size_t>(Class::Boolean)>(&d); }
 
-      Data d;
+      Data d{nullptr};
     };
 
     Internal internal;
@@ -131,10 +128,10 @@ namespace chaiscript::json {
       }
       JSONWrapper(std::nullptr_t) {}
 
-      typename Container::iterator begin() { return object ? object->begin() : typename Container::iterator(); }
-      typename Container::iterator end() { return object ? object->end() : typename Container::iterator(); }
-      typename Container::const_iterator begin() const { return object ? object->begin() : typename Container::iterator(); }
-      typename Container::const_iterator end() const { return object ? object->end() : typename Container::iterator(); }
+      Container::iterator begin() { return object ? object->begin() : typename Container::iterator(); }
+      Container::iterator end() { return object ? object->end() : typename Container::iterator(); }
+      [[nodiscard]] Container::const_iterator begin() const { return object ? object->begin() : typename Container::iterator(); }
+      [[nodiscard]] Container::const_iterator end() const { return object ? object->end() : typename Container::iterator(); }
     };
 
     template<typename Container>
@@ -147,10 +144,10 @@ namespace chaiscript::json {
       }
       JSONConstWrapper(std::nullptr_t) {}
 
-      typename Container::const_iterator begin() const noexcept {
+      [[nodiscard]] Container::const_iterator begin() const noexcept {
         return object ? object->begin() : typename Container::const_iterator();
       }
-      typename Container::const_iterator end() const noexcept { return object ? object->end() : typename Container::const_iterator(); }
+      [[nodiscard]] Container::const_iterator end() const noexcept { return object ? object->end() : typename Container::const_iterator(); }
     };
 
     JSON() = default;
@@ -162,7 +159,9 @@ namespace chaiscript::json {
 
     JSON(initializer_list<JSON> list)
         : internal(Class::Object) {
-      for (auto i = list.begin(), e = list.end(); i != e; ++i, ++i) {
+      for (auto i = list.begin(), e = list.end();
+           i != e;
+           std::advance(i, 2)) {
         operator[](i->to_string()) = *std::next(i);
       }
     }
@@ -471,22 +470,8 @@ namespace chaiscript::json {
                 }
               }
               offset += 4;
-              const auto ch = static_cast<uint32_t>(std::stoi(hex_matches, nullptr, 16));
-              if (ch < 0x80) {
-                val += static_cast<char>(ch);
-              } else if (ch < 0x800) {
-                val += static_cast<char>(0xC0 | (ch >> 6));
-                val += static_cast<char>(0x80 | (ch & 0x3F));
-              } else if (ch < 0x10000) {
-                val += static_cast<char>(0xE0 | (ch >> 12));
-                val += static_cast<char>(0x80 | ((ch >> 6) & 0x3F));
-                val += static_cast<char>(0x80 | (ch & 0x3F));
-              } else if (ch < 0x200000) {
-                val += static_cast<char>(0xF0 | (ch >> 18));
-                val += static_cast<char>(0x80 | ((ch >> 12) & 0x3F));
-                val += static_cast<char>(0x80 | ((ch >> 6) & 0x3F));
-                val += static_cast<char>(0x80 | (ch & 0x3F));
-              } else {
+              const auto ch = static_cast<std::uint32_t>(std::stoi(hex_matches, nullptr, 16));
+              if (chaiscript::utility::unicode::append_utf8(val, ch) == 0) {
                 throw std::runtime_error(std::string("JSON ERROR: String: Invalid 32 bit universal character"));
               }
             } break;

include/chaiscript/utility/json_wrap.hpp

@@ -1,6 +1,7 @@
 #ifndef CHAISCRIPT_SIMPLEJSON_WRAP_HPP
 #define CHAISCRIPT_SIMPLEJSON_WRAP_HPP
 
+#include "../dispatchkit/dynamic_object.hpp"
 #include "json.hpp"
 
 namespace chaiscript {
@@ -8,7 +9,10 @@ namespace chaiscript {
   public:
     static Module &library(Module &m) {
       m.add(chaiscript::fun([](const std::string &t_str) { return from_json(t_str); }), "from_json");
+      m.add(chaiscript::fun([](const std::string &t_str) { return object_from_json(t_str); }), "object_from_json");
       m.add(chaiscript::fun(&json_wrap::to_json), "to_json");
+      m.add(chaiscript::fun(&json_wrap::map_to_object), "map_to_object");
+      m.add(chaiscript::fun(&json_wrap::object_to_map), "object_to_map");
 
       return m;
     }
@@ -57,6 +61,63 @@ namespace chaiscript {
       }
     }
 
+    static Boxed_Value object_from_json(const json::JSON &t_json) {
+      switch (t_json.JSONType()) {
+        case json::JSON::Class::Null:
+          return Boxed_Value();
+        case json::JSON::Class::Object: {
+          auto obj = dispatch::Dynamic_Object("JSON_Object");
+
+          for (const auto &p : t_json.object_range()) {
+            obj.get_attr(p.first) = object_from_json(p.second);
+          }
+
+          return Boxed_Value(std::move(obj));
+        }
+        case json::JSON::Class::Array: {
+          std::vector<Boxed_Value> vec;
+
+          for (const auto &p : t_json.array_range()) {
+            vec.emplace_back(object_from_json(p));
+          }
+
+          return Boxed_Value(vec);
+        }
+        case json::JSON::Class::String:
+          return Boxed_Value(t_json.to_string());
+        case json::JSON::Class::Floating:
+          return Boxed_Value(t_json.to_float());
+        case json::JSON::Class::Integral:
+          return Boxed_Value(t_json.to_int());
+        case json::JSON::Class::Boolean:
+          return Boxed_Value(t_json.to_bool());
+      }
+
+      throw std::runtime_error("Unknown JSON type");
+    }
+
+    static Boxed_Value object_from_json(const std::string &t_json) {
+      try {
+        return object_from_json(json::JSON::Load(t_json));
+      } catch (const std::out_of_range &) {
+        throw std::runtime_error("Unparsed JSON input");
+      }
+    }
+
+    static Boxed_Value map_to_object(const std::map<std::string, Boxed_Value> &t_map) {
+      auto obj = dispatch::Dynamic_Object("JSON_Object");
+
+      for (const auto &p : t_map) {
+        obj.get_attr(p.first) = p.second;
+      }
+
+      return Boxed_Value(std::move(obj));
+    }
+
+    static std::map<std::string, Boxed_Value> object_to_map(const dispatch::Dynamic_Object &t_obj) {
+      return t_obj.get_attrs();
+    }
+
     static std::string to_json(const Boxed_Value &t_bv) { return to_json_object(t_bv).dump(); }
 
     static json::JSON to_json_object(const Boxed_Value &t_bv) {

include/chaiscript/utility/static_string.hpp

@@ -7,6 +7,8 @@
 #ifndef CHAISCRIPT_UTILITY_STATIC_STRING_HPP_
 #define CHAISCRIPT_UTILITY_STATIC_STRING_HPP_
 
+#include <iterator>
+
 namespace chaiscript::utility {
   struct Static_String {
     template<size_t N>
@@ -21,30 +23,17 @@ namespace chaiscript::utility {
 
     constexpr auto begin() const noexcept { return data; }
 
-    constexpr auto end() const noexcept { return data + m_size; }
+    constexpr auto end() const noexcept { return std::next(data, static_cast<std::ptrdiff_t>(m_size)); }
 
-    constexpr bool operator==(std::string_view other) const noexcept {
-      // return std::string_view(data, m_size) == other;
-      auto b1 = begin();
-      const auto e1 = end();
-      auto b2 = other.begin();
-      const auto e2 = other.end();
-
-      if (e1 - b1 != e2 - b2) {
-        return false;
-      }
-
-      while (b1 != e1) {
-        if (*b1 != *b2) {
-          return false;
-        }
-        ++b1;
-        ++b2;
-      }
-      return true;
+    constexpr auto operator[](const std::size_t idx) const noexcept {
+      return *std::next(data, static_cast<std::ptrdiff_t>(idx));
     }
 
-    bool operator==(const std::string &t_str) const noexcept { return std::equal(begin(), end(), std::cbegin(t_str), std::cend(t_str)); }
+    constexpr bool operator==(std::string_view other) const noexcept {
+      return std::string_view(data, m_size) == other;
+    }
+
+    constexpr bool operator==(const std::string &t_str) const noexcept { return std::equal(begin(), end(), std::cbegin(t_str), std::cend(t_str)); }
 
     const size_t m_size;
     const char *data = nullptr;

include/chaiscript/utility/unicode.hpp

@@ -0,0 +1,93 @@
+// This file is distributed under the BSD License.
+// See "license.txt" for details.
+// http://www.chaiscript.com
+
+#ifndef CHAISCRIPT_UTILITY_UNICODE_HPP_
+#define CHAISCRIPT_UTILITY_UNICODE_HPP_
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+
+namespace chaiscript {
+  namespace utility {
+    namespace unicode {
+
+      inline constexpr std::uint32_t max_codepoint = 0x10FFFF;
+
+      constexpr bool is_surrogate(std::uint32_t cp) noexcept {
+        return cp >= 0xD800 && cp <= 0xDFFF;
+      }
+
+      // Append cp to out as UTF-8. Returns bytes written, or 0 if cp >= 0x200000.
+      // Surrogates are not rejected here; callers that care check is_surrogate() first.
+      inline std::size_t append_utf8(std::string &out, std::uint32_t cp) {
+        if (cp < 0x80) {
+          out += static_cast<char>(cp);
+          return 1;
+        }
+        if (cp < 0x800) {
+          out += static_cast<char>(0xC0 | (cp >> 6));
+          out += static_cast<char>(0x80 | (cp & 0x3F));
+          return 2;
+        }
+        if (cp < 0x10000) {
+          out += static_cast<char>(0xE0 | (cp >> 12));
+          out += static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
+          out += static_cast<char>(0x80 | (cp & 0x3F));
+          return 3;
+        }
+        if (cp < 0x200000) {
+          out += static_cast<char>(0xF0 | (cp >> 18));
+          out += static_cast<char>(0x80 | ((cp >> 12) & 0x3F));
+          out += static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
+          out += static_cast<char>(0x80 | (cp & 0x3F));
+          return 4;
+        }
+        return 0;
+      }
+
+      // Append cp to out as UTF-16. Returns code units written, or 0 if cp is
+      // a surrogate or > max_codepoint.
+      template<typename CharT>
+      inline std::size_t append_utf16(std::basic_string<CharT> &out, std::uint32_t cp) {
+        if (is_surrogate(cp) || cp > max_codepoint) {
+          return 0;
+        }
+        if (cp < 0x10000) {
+          out += static_cast<CharT>(cp);
+          return 1;
+        }
+        const std::uint32_t v = cp - 0x10000;
+        out += static_cast<CharT>(0xD800 | (v >> 10));
+        out += static_cast<CharT>(0xDC00 | (v & 0x3FF));
+        return 2;
+      }
+
+      // Append cp to a basic_string<CharT>. Dispatches on sizeof(CharT):
+      // 1 byte -> UTF-8, 2 bytes -> UTF-16, 4 bytes -> UTF-32.
+      // Returns code units written, or 0 if the codepoint is invalid.
+      template<typename CharT>
+      inline std::size_t append_codepoint(std::basic_string<CharT> &out, std::uint32_t cp) {
+        if constexpr (sizeof(CharT) == 1) {
+          std::string tmp;
+          const auto n = append_utf8(tmp, cp);
+          out.append(tmp.begin(), tmp.end());
+          return n;
+        } else if constexpr (sizeof(CharT) == 2) {
+          return append_utf16(out, cp);
+        } else {
+          static_assert(sizeof(CharT) == 4, "append_codepoint: unsupported CharT size");
+          if (is_surrogate(cp) || cp > max_codepoint) {
+            return 0;
+          }
+          out += static_cast<CharT>(cp);
+          return 1;
+        }
+      }
+
+    } // namespace unicode
+  } // namespace utility
+} // namespace chaiscript
+
+#endif

readme.md

@@ -91,6 +91,16 @@ the doxygen documentation in the build folder or see the website
 http://www.chaiscript.com.
 
 
+Grammar
+=======
+
+A formal EBNF grammar for ChaiScript is available in
+[grammar/chaiscript.ebnf](grammar/chaiscript.ebnf). To view it as a railroad
+diagram, paste the grammar into
+[mingodad's railroad diagram generator](https://mingodad.github.io/plgh/json2ebnf.html)
+or [bottlecaps.de/rr](https://www.bottlecaps.de/rr/ui).
+
+
 The shortest complete example possible follows:
 
 ```C++

releasenotes.md

@@ -4,6 +4,7 @@ Current Version: 6.1.1
 
 ### Changes since 6.1.0
 
+ * Add `set_file_reader` callback for custom file loading #116 — allows overriding how `eval_file` and `use` read files
  * Handle the returning of `&` to `*` types. This specifically comes up with `std::vector<int *>` and similar containers
  * Update CMake to use `LIBDIR` instead of `lib` #502 by @guoyunhe
  * Add documentation for installing ChaiScript with vcpkg #500 by @grdowns

samples/fun_call_performance.cpp

@@ -30,9 +30,8 @@ char *mystrdup(const char *s) {
 #ifdef CHAISCRIPT_MSVC
   strcpy_s(d, len + 1, s); // Copy the characters
 #else
-  strncpy(d, s, len); // Copy the characters
+  strncpy(d, s, len + 1); // Copy the characters
 #endif
-  d[len] = '\0';
   return d; // Return the new string
 }
 
@@ -297,7 +296,7 @@ int main(int argc, char *argv[]) {
       ++i;
     }
 
-    std::string arg(i ? argv[i] : "--interactive");
+    std::string arg(i ? *std::next(argv, i) : "--interactive");
 
     enum {
       eInteractive,
@@ -311,7 +310,7 @@ int main(int argc, char *argv[]) {
         std::cout << "insufficient input following " << arg << std::endl;
         return EXIT_FAILURE;
       } else {
-        arg = argv[++i];
+        arg = *std::next(argv, ++i);
       }
     } else if (arg == "-" || arg == "--stdin") {
       arg = "";

src/libfuzzer_client.cpp

@@ -35,9 +35,8 @@ char *mystrdup(const char *s) {
 #ifdef CHAISCRIPT_MSVC
   strcpy_s(d, len + 1, s); // Copy the characters
 #else
-  strncpy(d, s, len); // Copy the characters
+  strncpy(d, s, len + 1); // Copy the characters
 #endif
-  d[len] = '\0';
   return d; // Return the new string
 }
 

src/main.cpp

@@ -8,6 +8,7 @@
 // PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
 #include <chrono>
+#include <cstddef>
 #include <iostream>
 #include <list>
 #include <regex>
@@ -34,9 +35,8 @@ char *mystrdup(const char *s) {
 #ifdef CHAISCRIPT_MSVC
   strcpy_s(d, len + 1, s); // Copy the characters
 #else
-  strncpy(d, s, len); // Copy the characters
+  strncpy(d, s, len + 1); // Copy the characters
 #endif
-  d[len] = '\0';
   return d; // Return the new string
 }
 
@@ -283,7 +283,7 @@ int main(int argc, char *argv[]) {
       ++i;
     }
 
-    std::string arg(i != 0 ? argv[i] : "--interactive");
+    std::string arg(i != 0 ? *std::next(argv, i) : "--interactive");
 
     enum {
       eInteractive,
@@ -297,7 +297,7 @@ int main(int argc, char *argv[]) {
         std::cout << "insufficient input following " << arg << '\n';
         return EXIT_FAILURE;
       }
-      arg = argv[++i];
+      arg = *std::next(argv, ++i);
 
     } else if (arg == "-" || arg == "--stdin") {
       arg = "";

src/sha3.h

@@ -6,20 +6,19 @@
 
 #pragma once
 
-//#include "hash.h"
+// #include "hash.h"
 #include <string>
 
 // define fixed size integer types
 #ifdef _MSC_VER
 // Windows
-typedef unsigned __int8  uint8_t;
+typedef unsigned __int8 uint8_t;
 typedef unsigned __int64 uint64_t;
 #else
 // GCC
 #include <stdint.h>
 #endif
 
-
 /// compute SHA3 hash
 /** Usage:
     SHA3 sha3;
@@ -37,18 +36,21 @@ class SHA3 //: public Hash
 {
 public:
   /// algorithm variants
-  enum Bits { Bits224 = 224, Bits256 = 256, Bits384 = 384, Bits512 = 512 };
+  enum Bits { Bits224 = 224,
+              Bits256 = 256,
+              Bits384 = 384,
+              Bits512 = 512 };
 
   /// same as reset()
   explicit SHA3(Bits bits = Bits256);
 
   /// compute hash of a memory block
-  std::string operator()(const void* data, size_t numBytes);
+  std::string operator()(const void *data, size_t numBytes);
   /// compute hash of a string, excluding final zero
-  std::string operator()(const std::string& text);
+  std::string operator()(const std::string &text);
 
   /// add arbitrary number of bytes
-  void add(const void* data, size_t numBytes);
+  void add(const void *data, size_t numBytes);
 
   /// return latest hash as hex characters
   std::string getHash();
@@ -58,24 +60,24 @@ public:
 
 private:
   /// process a full block
-  void processBlock(const void* data);
+  void processBlock(const void *data);
   /// process everything left in the internal buffer
   void processBuffer();
 
   /// 1600 bits, stored as 25x64 bit, BlockSize is no more than 1152 bits (Keccak224)
-  enum { StateSize    = 1600 / (8 * 8),
-         MaxBlockSize =  200 - 2 * (224 / 8) };
+  enum { StateSize = 1600 / (8 * 8),
+         MaxBlockSize = 200 - 2 * (224 / 8) };
 
   /// hash
   uint64_t m_hash[StateSize];
   /// size of processed data in bytes
   uint64_t m_numBytes;
   /// block size (less or equal to MaxBlockSize)
-  size_t   m_blockSize;
+  size_t m_blockSize;
   /// valid bytes in m_buffer
-  size_t   m_bufferSize;
+  size_t m_bufferSize;
   /// bytes not processed yet
-  uint8_t  m_buffer[MaxBlockSize];
+  uint8_t m_buffer[MaxBlockSize];
   /// variant
-  Bits     m_bits;
+  Bits m_bits;
 };

unittests/assign_no_aliasing.chai

@@ -0,0 +1,41 @@
+// Issue #635: optimized for loop with := must not produce dangling values
+// := is reference-assign, so ret aliases i and sees the loop exit value
+
+// Basic: capture loop variable via :=
+var ret = 0
+for (var i = 0; i < 100; ++i) {
+  ret := i
+}
+assert_equal(100, ret)
+
+// Return from function containing optimized for loop
+def loop_result() {
+  var ret = 0
+  for (var i = 0; i < 200; ++i) {
+    ret := i
+  }
+  return ret
+}
+assert_equal(200, loop_result())
+
+// Multiple calls return consistent results
+assert_equal(loop_result(), loop_result())
+
+// Nested optimized for loops
+var outer_val = 0
+var inner_val = 0
+for (var i = 0; i < 10; ++i) {
+  for (var j = 0; j < 10; ++j) {
+    inner_val := j
+  }
+  outer_val := i
+}
+assert_equal(10, outer_val)
+assert_equal(10, inner_val)
+
+// Value-assign (=) captures last body-iteration value, not exit value
+var ret2 = 0
+for (var i = 0; i < 100; ++i) {
+  ret2 = i
+}
+assert_equal(99, ret2)

unittests/async_engine_lifetime.chai

@@ -0,0 +1,17 @@
+// Regression test for #632 and #636: Heap-use-after-free in async threads
+// Async threads must complete before the engine is destroyed.
+
+var func = fun(){
+  var ret = 0;
+  for (var i = 0; i < 1000; ++i) {
+    ret += i;
+  }
+  return ret;
+}
+
+var fut1 = async(func);
+var fut2 = async(func);
+
+// Wait for results to verify correctness
+assert_equal(fut1.get(), 499500);
+assert_equal(fut2.get(), 499500);

unittests/async_engine_lifetime_test.cpp

@@ -0,0 +1,46 @@
+// Regression test for #632 and #636:
+// Heap-use-after-free when async threads outlive the ChaiScript engine.
+// The engine must join all outstanding async threads before destroying shared state.
+
+#include <chaiscript/chaiscript.hpp>
+
+int main() {
+  // Test 1: Async threads still running when engine is destroyed.
+  // Without the fix, this triggers heap-use-after-free under ASAN/TSAN.
+  for (int iter = 0; iter < 3; ++iter) {
+    {
+      chaiscript::ChaiScript chai;
+      try {
+        chai.eval(R"(
+          var func = fun(){
+            var ret = 0;
+            for (var i = 0; i < 5000; ++i) {
+              ret += i;
+            }
+            return ret;
+          }
+
+          var fut1 = async(func);
+          var fut2 = async(func);
+        )");
+        // Engine destroyed here without waiting for futures.
+      } catch (const std::exception &) {
+        // Exceptions are fine
+      }
+    }
+  }
+
+  // Test 2: Verify async still works correctly (results are accessible).
+  {
+    chaiscript::ChaiScript chai;
+    auto result = chai.eval<int>(R"(
+      var f = async(fun() { return 42; });
+      f.get();
+    )");
+    if (result != 42) {
+      return EXIT_FAILURE;
+    }
+  }
+
+  return EXIT_SUCCESS;
+}

unittests/async_return_value.chai

@@ -0,0 +1,25 @@
+// Issue #635: async + optimized for loop must not segfault from dangling pointer
+// := is reference-assign, so ret aliases i and sees the loop exit value
+
+var func = fun(){
+  var ret = 0;
+  for (var i = 0; i < 1000; ++i) {
+    ret := i;
+  }
+  return ret;
+}
+
+var&fut1 = async(func);
+var fut2 = async(func);
+
+assert_equal(1000, fut1.get())
+assert_equal(1000, fut2.get())
+
+// Multiple concurrent async calls to stress the scenario
+var results = []
+for (var n = 0; n < 5; ++n) {
+  results.push_back(async(func))
+}
+for (var n = 0; n < 5; ++n) {
+  assert_equal(1000, results[n].get())
+}

unittests/conversion_functions.chai

@@ -0,0 +1,33 @@
+// Test that all conversion functions work across char, int, and string types
+
+// char() constructor
+assert_equal('A', char('A'))   // char from char (identity via Boxed_Number)
+assert_equal('A', char(65))    // char from int (via Boxed_Number)
+assert_equal('A', char("A"))   // char from string (new)
+
+// to_char() conversions
+assert_equal('A', to_char('A'))   // to_char from char (identity)
+assert_equal('A', to_char(65))    // to_char from int (new, via Boxed_Number)
+assert_equal('A', to_char("A"))   // to_char from string (existing)
+
+// int() constructor
+assert_equal(65, int('A'))   // int from char (via Boxed_Number)
+assert_equal(65, int(65))    // int from int (identity via Boxed_Number)
+assert_equal(65, int("65"))  // int from string (new)
+
+// to_int() conversions
+assert_equal(65, to_int('A'))    // to_int from char (new, via Boxed_Number)
+assert_equal(65, to_int(65))     // to_int from int (identity)
+assert_equal(65, to_int("65"))   // to_int from string (existing)
+
+// to_string() conversions
+assert_equal("A", to_string('A'))
+assert_equal("65", to_string(65))
+assert_equal("A", to_string("A"))
+
+// double conversions
+assert_equal(3.5, double("3.5"))       // double from string (new)
+assert_equal(3.5, to_double("3.5"))    // to_double from string (existing)
+assert_equal(65.0, to_double('A'))     // to_double from char (new, via Boxed_Number)
+assert_equal(65.0, to_double(65))      // to_double from int (new, via Boxed_Number)
+assert_equal("3.5", to_string(3.5))    // to_string from double (existing)

unittests/emscripten_eval_test.cpp

@@ -9,43 +9,64 @@
 #define CHAISCRIPT_NO_DYNLOAD
 #endif
 
-#include <chaiscript/chaiscript.hpp>
 #include "../emscripten/chaiscript_eval.hpp"
 #include <cassert>
+#include <chaiscript/chaiscript.hpp>
 #include <cmath>
 #include <string>
 
 int main() {
+  const int chai = chaiscript_create();
+  assert(chai > 0 && "create must return a positive handle");
+
   // Test eval (void return) - same as Emscripten eval()
-  chaiscript_eval("var x = 42");
+  chaiscript_eval(chai, "var x = 42");
 
   // Test evalString - same as Emscripten evalString()
-  std::string s = chaiscript_eval_string("to_string(x)");
+  [[maybe_unused]] const std::string s = chaiscript_eval_string(chai, "to_string(x)");
   assert(s == "42");
 
   // Test evalInt - same as Emscripten evalInt()
-  int i = chaiscript_eval_int("1 + 2");
+  [[maybe_unused]] const int i = chaiscript_eval_int(chai, "1 + 2");
   assert(i == 3);
 
   // Test evalBool - same as Emscripten evalBool()
-  bool b = chaiscript_eval_bool("true");
+  [[maybe_unused]] bool b = chaiscript_eval_bool(chai, "true");
   assert(b == true);
 
-  b = chaiscript_eval_bool("false");
+  b = chaiscript_eval_bool(chai, "false");
   assert(b == false);
 
   // Test evalFloat - same as Emscripten evalFloat()
-  float f = chaiscript_eval_float("1.5f");
+  [[maybe_unused]] const float f = chaiscript_eval_float(chai, "1.5f");
   assert(std::abs(f - 1.5f) < 0.001f);
 
   // Test evalDouble - same as Emscripten evalDouble()
-  double d = chaiscript_eval_double("3.14");
+  [[maybe_unused]] const double d = chaiscript_eval_double(chai, "3.14");
   assert(std::abs(d - 3.14) < 0.001);
 
   // Test a more complex expression
-  chaiscript_eval("def square(n) { return n * n; }");
-  int sq = chaiscript_eval_int("square(7)");
+  chaiscript_eval(chai, "def square(n) { return n * n; }");
+  [[maybe_unused]] const int sq = chaiscript_eval_int(chai, "square(7)");
   assert(sq == 49);
 
+  // A second engine is fully independent of the first.
+  const int chai2 = chaiscript_create();
+  assert(chai2 != chai && "create must mint a fresh handle each call");
+  [[maybe_unused]] bool caught = false;
+  try {
+    chaiscript_eval(chai2, "x");
+  } catch (const chaiscript::exception::eval_error &) {
+    caught = true;
+  }
+  assert(caught && "engines must not share globals");
+
+  chaiscript_destroy(chai2);
+  chaiscript_destroy(chai);
+
+  // Destroying an unknown handle is a no-op.
+  chaiscript_destroy(chai);
+  chaiscript_destroy(99999);
+
   return 0;
 }

unittests/emscripten_exception_test.cpp

@@ -0,0 +1,77 @@
+// Test that validates exception propagation through the Emscripten eval wrapper.
+// Without proper exception support flags (-fwasm-exceptions) in the WASM build,
+// C++ exceptions would cause an abort instead of being catchable.
+
+#ifndef CHAISCRIPT_NO_THREADS
+#define CHAISCRIPT_NO_THREADS
+#endif
+
+#ifndef CHAISCRIPT_NO_DYNLOAD
+#define CHAISCRIPT_NO_DYNLOAD
+#endif
+
+#include "../emscripten/chaiscript_eval.hpp"
+#include <cassert>
+#include <chaiscript/chaiscript.hpp>
+#include <iostream>
+#include <stdexcept>
+#include <string>
+
+int main() {
+  // Verify that ChaiScript evaluation errors propagate as exceptions
+  // through the eval wrapper functions. In WASM builds without exception
+  // support, these would abort instead of throwing.
+
+  const int chai = chaiscript_create();
+
+  [[maybe_unused]] bool caught = false;
+
+  // Test 1: eval with undefined variable should throw
+  caught = false;
+  try {
+    chaiscript_eval(chai, "this_variable_does_not_exist");
+  } catch (const chaiscript::exception::eval_error &) {
+    caught = true;
+  }
+  assert(caught && "eval of undefined variable must throw eval_error");
+
+  // Test 2: evalString with a type mismatch should throw
+  caught = false;
+  try {
+    chaiscript_eval_string(chai, "1 + 2");
+  } catch (const chaiscript::exception::bad_boxed_cast &) {
+    caught = true;
+  }
+  assert(caught && "evalString with non-string result must throw bad_boxed_cast");
+
+  // Test 3: evalInt with invalid syntax should throw
+  caught = false;
+  try {
+    chaiscript_eval_int(chai, "def {}");
+  } catch (const chaiscript::exception::eval_error &) {
+    caught = true;
+  }
+  assert(caught && "evalInt with syntax error must throw eval_error");
+
+  // Test 4: eval with throw statement should propagate exception
+  caught = false;
+  try {
+    chaiscript_eval(chai, "throw(\"user exception\")");
+  } catch (const chaiscript::Boxed_Value &) {
+    caught = true;
+  } catch (...) {
+    caught = true;
+  }
+  assert(caught && "ChaiScript throw must propagate as an exception");
+
+  // Test 5: Verify normal operation still works after caught exceptions
+  chaiscript_eval(chai, "var post_exception_test = 100");
+
+  [[maybe_unused]] const int result = chaiscript_eval_int(chai, "post_exception_test");
+  assert(result == 100 && "normal eval must work after caught exceptions");
+
+  chaiscript_destroy(chai);
+
+  std::cout << "All emscripten exception tests passed.\n";
+  return 0;
+}

unittests/emscripten_state_test.cpp

@@ -0,0 +1,76 @@
+// Test that validates the save/restore/release state helpers used by the
+// Emscripten wrapper. A handle-based registry is exposed so the JS playground
+// can capture a pristine engine once and restore it between runs without
+// reloading the WASM module.
+
+#ifndef CHAISCRIPT_NO_THREADS
+#define CHAISCRIPT_NO_THREADS
+#endif
+
+#ifndef CHAISCRIPT_NO_DYNLOAD
+#define CHAISCRIPT_NO_DYNLOAD
+#endif
+
+#include "../emscripten/chaiscript_eval.hpp"
+#include <cassert>
+#include <chaiscript/chaiscript.hpp>
+#include <string>
+
+int main() {
+  const int chai = chaiscript_create();
+  assert(chai > 0 && "create must return a positive handle");
+
+  // Capture a baseline before any user code has been evaluated.
+  const int baseline = chaiscript_save_state(chai);
+  assert(baseline > 0 && "saveState must return a positive handle");
+
+  // Distinct calls produce distinct handles.
+  const int second = chaiscript_save_state(chai);
+  assert(second != baseline && "saveState must mint a fresh handle each call");
+  chaiscript_release_state(second);
+
+  // Define a global that did not exist in the baseline.
+  chaiscript_eval(chai, "var post_baseline_marker = 123");
+  assert(chaiscript_eval_int(chai, "post_baseline_marker") == 123);
+
+  // Restoring the baseline must drop the post-baseline definition: evaluating
+  // it should now fail with eval_error because the variable is undefined.
+  chaiscript_restore_state(chai, baseline);
+
+  [[maybe_unused]] bool caught = false;
+  try {
+    chaiscript_eval(chai, "post_baseline_marker");
+  } catch (const chaiscript::exception::eval_error &) {
+    caught = true;
+  }
+  assert(caught && "restoreState must drop globals defined after the snapshot");
+
+  // The engine remains usable after a restore.
+  chaiscript_eval(chai, "var after_restore = 7");
+  assert(chaiscript_eval_int(chai, "after_restore * 6") == 42);
+
+  // Releasing the handle is required so the registry does not grow unbounded.
+  chaiscript_release_state(baseline);
+
+  // Releasing a handle that was never minted (or has already been released) is
+  // a no-op rather than an error.
+  chaiscript_release_state(baseline);
+  chaiscript_release_state(99999);
+
+  // Restoring an unknown handle is a no-op: state must be unchanged.
+  chaiscript_restore_state(chai, 99999);
+  assert(chaiscript_eval_int(chai, "after_restore") == 7);
+
+  // A snapshot taken on one engine can be restored onto a different engine,
+  // confirming that state is decoupled from any particular instance.
+  const int snapshot_with_after_restore = chaiscript_save_state(chai);
+  const int chai2 = chaiscript_create();
+  chaiscript_restore_state(chai2, snapshot_with_after_restore);
+  assert(chaiscript_eval_int(chai2, "after_restore") == 7);
+
+  chaiscript_release_state(snapshot_with_after_restore);
+  chaiscript_destroy(chai2);
+  chaiscript_destroy(chai);
+
+  return 0;
+}

unittests/enum.chai

@@ -0,0 +1,110 @@
+// Basic enum class definition (default underlying type: int)
+enum class Color { Red, Green, Blue }
+
+// Access via :: syntax
+auto r = Color::Red
+auto g = Color::Green
+auto b = Color::Blue
+
+// Equality and inequality
+assert_true(Color::Red == Color::Red)
+assert_false(Color::Red == Color::Green)
+assert_true(Color::Red != Color::Green)
+assert_false(Color::Red != Color::Red)
+
+// Constructor from valid underlying value
+auto c = Color::Color(1)
+assert_true(c == Color::Green)
+
+// Constructor from invalid value throws
+try {
+  Color::Color(52)
+  assert_true(false)
+} catch(e) {
+  // expected
+}
+
+// Strong typing: function with typed parameter
+def takes_color(Color val) { val }
+takes_color(Color::Red)
+takes_color(Color::Green)
+takes_color(Color::Color(2))
+
+// Cannot pass int where Color is expected
+try {
+  takes_color(52)
+  assert_true(false)
+} catch(e) {
+  // expected: dispatch error
+}
+
+// to_underlying accessor
+assert_equal(0, Color::Red.to_underlying())
+assert_equal(1, Color::Green.to_underlying())
+assert_equal(2, Color::Blue.to_underlying())
+
+// Enum class with explicit values
+enum class Priority { Low = 10, Medium = 20, High = 30 }
+assert_equal(10, Priority::Low.to_underlying())
+assert_equal(20, Priority::Medium.to_underlying())
+assert_equal(30, Priority::High.to_underlying())
+
+auto p = Priority::Priority(20)
+assert_true(p == Priority::Medium)
+
+// Mixed auto and explicit values
+enum class Status { Pending, Active = 5, Done }
+assert_equal(0, Status::Pending.to_underlying())
+assert_equal(5, Status::Active.to_underlying())
+assert_equal(6, Status::Done.to_underlying())
+
+// Switch on enum values
+var result = ""
+switch(Color::Green) {
+  case (Color::Red) {
+    result = "red"
+    break
+  }
+  case (Color::Green) {
+    result = "green"
+    break
+  }
+  case (Color::Blue) {
+    result = "blue"
+    break
+  }
+}
+assert_equal("green", result)
+
+// Switch on enum with explicit values
+var prio_result = ""
+switch(Priority::High) {
+  case (Priority::Low) {
+    prio_result = "low"
+    break
+  }
+  case (Priority::Medium) {
+    prio_result = "medium"
+    break
+  }
+  case (Priority::High) {
+    prio_result = "high"
+    break
+  }
+}
+assert_equal("high", prio_result)
+
+// Enum class with explicit underlying type
+enum class Flags : char { Read = 1, Write = 2, Execute = 4 }
+assert_equal(1, Flags::Read.to_underlying())
+assert_equal(2, Flags::Write.to_underlying())
+assert_equal(4, Flags::Execute.to_underlying())
+
+auto f = Flags::Flags(2)
+assert_true(f == Flags::Write)
+
+// enum struct syntax (equivalent to enum class, like C++)
+enum struct Direction { North, East, South, West }
+assert_equal(0, Direction::North.to_underlying())
+assert_equal(3, Direction::West.to_underlying())
+assert_true(Direction::East != Direction::South)

unittests/exception_comprehensive.chai

@@ -0,0 +1,862 @@
+// Comprehensive exception throwing and catching tests
+// Tests throw/catch from various contexts: operators, functions, lambdas,
+// methods, [] operator, nested scopes, and with various value types.
+
+// ============================================================
+// Section 1: Throwing and catching different value types
+// ============================================================
+
+// Throw int
+try {
+  throw(42)
+}
+catch(e) {
+  assert_equal(42, e)
+}
+
+// Throw string
+try {
+  throw("error message")
+}
+catch(e) {
+  assert_equal("error message", e)
+}
+
+// Throw double
+try {
+  throw(3.14)
+}
+catch(e) {
+  assert_equal(3.14, e)
+}
+
+// Throw bool
+try {
+  throw(true)
+}
+catch(e) {
+  assert_equal(true, e)
+}
+
+// Throw a Vector (via named variable to preserve mutability)
+auto thrown_vec = [1, 2, 3]
+try {
+  throw(thrown_vec)
+}
+catch(e) {
+  assert_equal(3, e.size())
+  assert_equal(1, e[0])
+  assert_equal(2, e[1])
+  assert_equal(3, e[2])
+}
+
+// Throw a Map (via named variable to preserve mutability)
+auto thrown_map = ["key": 42]
+try {
+  throw(thrown_map)
+}
+catch(e) {
+  assert_equal(42, e["key"])
+}
+
+// ============================================================
+// Section 2: Typed catch blocks
+// ============================================================
+
+// Typed catch matching int
+auto typed_result = 0
+try {
+  throw(10)
+}
+catch(int e) {
+  typed_result = e + 1
+}
+assert_equal(11, typed_result)
+
+// Typed catch matching string
+typed_result = 0
+try {
+  throw("hello")
+}
+catch(string e) {
+  typed_result = 1
+}
+assert_equal(1, typed_result)
+
+// Typed catch mismatch falls through to untyped
+typed_result = 0
+try {
+  throw(42)
+}
+catch(string e) {
+  typed_result = 1
+}
+catch(e) {
+  typed_result = 2
+}
+assert_equal(2, typed_result)
+
+// Multiple typed catches - first match wins
+typed_result = 0
+try {
+  throw("test")
+}
+catch(int e) {
+  typed_result = 1
+}
+catch(string e) {
+  typed_result = 2
+}
+catch(e) {
+  typed_result = 3
+}
+assert_equal(2, typed_result)
+
+// Typed catch with int, multiple typed blocks, none match except untyped
+typed_result = 0
+try {
+  throw(3.14)
+}
+catch(int e) {
+  typed_result = 1
+}
+catch(string e) {
+  typed_result = 2
+}
+catch(e) {
+  typed_result = 3
+}
+assert_equal(3, typed_result)
+
+// ============================================================
+// Section 3: Catch-all (no variable) catch block
+// ============================================================
+
+auto catch_all_reached = false
+try {
+  throw(99)
+}
+catch {
+  catch_all_reached = true
+}
+assert_true(catch_all_reached)
+
+// ============================================================
+// Section 4: Finally block semantics
+// ============================================================
+
+// Finally runs after exception
+auto finally_ran = false
+try {
+  throw(1)
+}
+catch(e) {
+  // caught
+}
+finally {
+  finally_ran = true
+}
+assert_true(finally_ran)
+
+// Finally runs without exception
+finally_ran = false
+try {
+  auto x = 1
+}
+catch(e) {
+  // not reached
+}
+finally {
+  finally_ran = true
+}
+assert_true(finally_ran)
+
+// Finally runs even with typed catch that matches
+finally_ran = false
+try {
+  throw(42)
+}
+catch(int e) {
+  assert_equal(42, e)
+}
+finally {
+  finally_ran = true
+}
+assert_true(finally_ran)
+
+// Finally runs when typed catch does NOT match (exception not caught)
+finally_ran = false
+auto outer_caught = false
+try {
+  try {
+    throw(42)
+  }
+  catch(string e) {
+    // wrong type, won't match
+  }
+  finally {
+    finally_ran = true
+  }
+}
+catch(e) {
+  outer_caught = true
+}
+assert_true(finally_ran)
+assert_true(outer_caught)
+
+// ============================================================
+// Section 5: Throwing from functions
+// ============================================================
+
+def throwing_function() {
+  throw("from function")
+}
+
+try {
+  throwing_function()
+}
+catch(e) {
+  assert_equal("from function", e)
+}
+
+// Throwing from nested function calls
+def inner_throw() {
+  throw("inner")
+}
+
+def outer_call() {
+  inner_throw()
+}
+
+try {
+  outer_call()
+}
+catch(e) {
+  assert_equal("inner", e)
+}
+
+// Function that throws conditionally
+def conditional_throw(should_throw) {
+  if (should_throw) {
+    throw("conditional")
+  }
+  return "no throw"
+}
+
+assert_equal("no throw", conditional_throw(false))
+
+try {
+  conditional_throw(true)
+}
+catch(e) {
+  assert_equal("conditional", e)
+}
+
+// ============================================================
+// Section 6: Throwing from lambdas
+// ============================================================
+
+auto throwing_lambda = fun() { throw("from lambda") }
+
+try {
+  throwing_lambda()
+}
+catch(e) {
+  assert_equal("from lambda", e)
+}
+
+// Lambda that captures and throws
+auto captured_val = "captured"
+auto capture_lambda = fun[captured_val]() { throw(captured_val) }
+
+try {
+  capture_lambda()
+}
+catch(e) {
+  assert_equal("captured", e)
+}
+
+// ============================================================
+// Section 7: Throwing from binary operators
+// ============================================================
+
+// Define a type and an operator that throws
+attr ThrowOnAdd::val
+def ThrowOnAdd::ThrowOnAdd(v) { this.val = v }
+
+def `+`(ThrowOnAdd x, ThrowOnAdd y) {
+  throw("add not supported")
+}
+
+try {
+  auto a = ThrowOnAdd(1)
+  auto b = ThrowOnAdd(2)
+  auto c = a + b
+  assert_true(false) // should not reach here
+}
+catch(e) {
+  assert_equal("add not supported", e)
+}
+
+// Operator that throws for specific values
+def `-`(ThrowOnAdd x, ThrowOnAdd y) {
+  if (x.val == y.val) {
+    throw("cannot subtract equal values")
+  }
+  return ThrowOnAdd(x.val - y.val)
+}
+
+try {
+  auto a = ThrowOnAdd(5)
+  auto b = ThrowOnAdd(5)
+  auto c = a - b
+  assert_true(false)
+}
+catch(e) {
+  assert_equal("cannot subtract equal values", e)
+}
+
+// Multiplication operator that throws (not pre-defined for Dynamic_Object)
+def `*`(ThrowOnAdd x, ThrowOnAdd y) {
+  throw("multiply not supported")
+}
+
+try {
+  auto a = ThrowOnAdd(1)
+  auto b = ThrowOnAdd(2)
+  auto c = a * b
+  assert_true(false)
+}
+catch(e) {
+  assert_equal("multiply not supported", e)
+}
+
+// Subtraction works for non-equal values
+auto sub_result = ThrowOnAdd(10) - ThrowOnAdd(3)
+assert_equal(7, sub_result.val)
+
+// ============================================================
+// Section 8: Throwing from unary/prefix operators
+// ============================================================
+
+def `++`(ThrowOnAdd x) {
+  throw("increment not supported")
+}
+
+try {
+  auto a = ThrowOnAdd(1)
+  ++a
+  assert_true(false)
+}
+catch(e) {
+  assert_equal("increment not supported", e)
+}
+
+// ============================================================
+// Section 9: Throwing from [] operator
+// ============================================================
+
+attr ThrowOnIndex::data
+def ThrowOnIndex::ThrowOnIndex() { this.data = [1, 2, 3] }
+
+def `[]`(ThrowOnIndex obj, int idx) {
+  if (idx < 0) {
+    throw("negative index not allowed")
+  }
+  return obj.data[idx]
+}
+
+auto toi = ThrowOnIndex()
+assert_equal(1, toi[0])
+assert_equal(2, toi[1])
+
+try {
+  auto val = toi[-1]
+  assert_true(false)
+}
+catch(e) {
+  assert_equal("negative index not allowed", e)
+}
+
+// ============================================================
+// Section 10: Throwing from member functions
+// ============================================================
+
+attr Validatable::value
+def Validatable::Validatable(v) { this.value = v }
+
+def Validatable::validate() {
+  if (this.value < 0) {
+    throw("validation failed: negative value")
+  }
+  return true
+}
+
+auto valid_obj = Validatable(10)
+assert_true(valid_obj.validate())
+
+auto invalid_obj = Validatable(-1)
+try {
+  invalid_obj.validate()
+  assert_true(false)
+}
+catch(e) {
+  assert_equal("validation failed: negative value", e)
+}
+
+// ============================================================
+// Section 11: Nested try/catch
+// ============================================================
+
+auto inner_caught = false
+auto outer_caught_val = 0
+try {
+  try {
+    throw(1)
+  }
+  catch(e) {
+    inner_caught = true
+    throw(e + 10)
+  }
+}
+catch(e) {
+  outer_caught_val = e
+}
+assert_true(inner_caught)
+assert_equal(11, outer_caught_val)
+
+// Deeply nested try/catch
+auto depth = 0
+try {
+  try {
+    try {
+      throw("deep")
+    }
+    catch(e) {
+      depth = 1
+      throw(e + "er")
+    }
+  }
+  catch(e) {
+    depth = 2
+    throw(e + "est")
+  }
+}
+catch(e) {
+  depth = 3
+  assert_equal("deeperest", e)
+}
+assert_equal(3, depth)
+
+// ============================================================
+// Section 12: Rethrow from catch block
+// ============================================================
+
+auto rethrow_caught = false
+try {
+  try {
+    throw("rethrown")
+  }
+  catch(e) {
+    throw(e)
+  }
+}
+catch(e) {
+  rethrow_caught = true
+  assert_equal("rethrown", e)
+}
+assert_true(rethrow_caught)
+
+// ============================================================
+// Section 13: Exception in for loop
+// ============================================================
+
+auto loop_exception_val = 0
+try {
+  for (auto i = 0; i < 10; ++i) {
+    if (i == 5) {
+      throw(i)
+    }
+  }
+}
+catch(e) {
+  loop_exception_val = e
+}
+assert_equal(5, loop_exception_val)
+
+// ============================================================
+// Section 14: Exception in while loop
+// ============================================================
+
+auto while_exc_val = 0
+auto counter = 0
+try {
+  while (true) {
+    ++counter
+    if (counter == 3) {
+      throw(counter)
+    }
+  }
+}
+catch(e) {
+  while_exc_val = e
+}
+assert_equal(3, while_exc_val)
+
+// ============================================================
+// Section 15: Exception preserves value through nested calls
+// ============================================================
+
+def deep_throw(val) {
+  throw(val)
+}
+
+def middle_call(val) {
+  deep_throw(val)
+}
+
+def top_call(val) {
+  middle_call(val)
+}
+
+auto nested_map = ["key": "value"]
+try {
+  top_call(nested_map)
+}
+catch(e) {
+  assert_equal("value", e["key"])
+}
+
+auto nested_vec = [10, 20, 30]
+try {
+  top_call(nested_vec)
+}
+catch(e) {
+  assert_equal(3, e.size())
+  assert_equal(20, e[1])
+}
+
+// ============================================================
+// Section 16: Code after throw is not executed
+// ============================================================
+
+auto after_throw = false
+try {
+  throw(1)
+  after_throw = true
+}
+catch(e) {
+  // caught
+}
+assert_false(after_throw)
+
+// ============================================================
+// Section 17: Exception value is usable in catch block arithmetic
+// ============================================================
+
+auto catch_computed = 0
+try {
+  throw(1)
+}
+catch(e) {
+  catch_computed = e + 100
+}
+assert_equal(101, catch_computed)
+
+// ============================================================
+// Section 18: No exception means catch is skipped
+// ============================================================
+
+auto catch_skipped = true
+try {
+  auto x = 42
+}
+catch(e) {
+  catch_skipped = false
+}
+assert_true(catch_skipped)
+
+// ============================================================
+// Section 19: Exception from dynamic object method chaining
+// ============================================================
+
+attr Chain::val
+def Chain::Chain(v) { this.val = v }
+
+def Chain::add(n) {
+  if (this.val + n > 100) {
+    throw("overflow: " + to_string(this.val + n))
+  }
+  this.val = this.val + n
+  return this
+}
+
+auto chain = Chain(50)
+try {
+  chain.add(30).add(30)
+  assert_true(false)
+}
+catch(e) {
+  assert_equal("overflow: 110", e)
+}
+assert_equal(80, chain.val)
+
+// ============================================================
+// Section 20: Exception thrown during map construction
+// ============================================================
+
+def exploding_value() {
+  throw("boom during construction")
+}
+
+try {
+  auto m = ["ok": 1, "bad": exploding_value()]
+  assert_true(false)
+}
+catch(e) {
+  assert_equal("boom during construction", e)
+}
+
+// ============================================================
+// Section 21: Exception thrown during vector construction
+// ============================================================
+
+try {
+  auto v = [1, 2, exploding_value(), 4]
+  assert_true(false)
+}
+catch(e) {
+  assert_equal("boom during construction", e)
+}
+
+// ============================================================
+// Section 22: Exception in if-condition
+// ============================================================
+
+def exploding_condition() {
+  throw("condition exploded")
+}
+
+try {
+  if (exploding_condition()) {
+    assert_true(false)
+  }
+}
+catch(e) {
+  assert_equal("condition exploded", e)
+}
+
+// ============================================================
+// Section 23: Multiple catch blocks - only first matching runs
+// ============================================================
+
+auto catch_count = 0
+try {
+  throw(42)
+}
+catch(int e) {
+  ++catch_count
+}
+catch(e) {
+  ++catch_count
+}
+assert_equal(1, catch_count)
+
+// ============================================================
+// Section 24: Throwing from within catch, with finally
+// ============================================================
+
+auto s24_finally = false
+auto s24_outer = false
+try {
+  try {
+    throw("original")
+  }
+  catch(e) {
+    throw("replaced: " + e)
+  }
+  finally {
+    s24_finally = true
+  }
+}
+catch(e) {
+  s24_outer = true
+  assert_equal("replaced: original", e)
+}
+assert_true(s24_finally)
+assert_true(s24_outer)
+
+// ============================================================
+// Section 25: Unhandled typed catch propagates exception
+// ============================================================
+
+auto s25_caught = false
+try {
+  try {
+    throw(3.14)
+  }
+  catch(int e) {
+    assert_true(false) // should not match double
+  }
+  catch(string e) {
+    assert_true(false) // should not match double
+  }
+}
+catch(e) {
+  s25_caught = true
+  assert_equal(3.14, e)
+}
+assert_true(s25_caught)
+
+// ============================================================
+// Section 26: Throw from range-based for
+// ============================================================
+
+auto s26_val = 0
+try {
+  for (x : [10, 20, 30, 40]) {
+    if (x == 30) {
+      throw(x)
+    }
+  }
+}
+catch(e) {
+  s26_val = e
+}
+assert_equal(30, s26_val)
+
+// ============================================================
+// Section 27: Throw from eval
+// ============================================================
+
+try {
+  eval("throw(\"from eval\")")
+}
+catch(e) {
+  assert_equal("from eval", e)
+}
+
+// ============================================================
+// Section 28: Exception from built-in operations (out of range)
+// ============================================================
+
+auto s28_caught = false
+try {
+  auto v = [1, 2, 3]
+  auto x = v[10]
+}
+catch(e) {
+  s28_caught = true
+}
+assert_true(s28_caught)
+
+// ============================================================
+// Section 29: Throw zero and empty string (falsy values)
+// ============================================================
+
+try {
+  throw(0)
+}
+catch(e) {
+  assert_equal(0, e)
+}
+
+try {
+  throw("")
+}
+catch(e) {
+  assert_equal("", e)
+}
+
+// ============================================================
+// Section 30: Throw from ternary-style inline_if
+// ============================================================
+
+def maybe_throw(do_it) {
+  if (do_it) { throw("inline threw") } else { "ok" }
+}
+
+try {
+  maybe_throw(true)
+}
+catch(e) {
+  assert_equal("inline threw", e)
+}
+assert_equal("ok", maybe_throw(false))
+
+// ============================================================
+// Section 31: Verify catch variable scope isolation
+// ============================================================
+
+auto outer_e = "untouched"
+try {
+  throw("caught_value")
+}
+catch(e) {
+  assert_equal("caught_value", e)
+}
+assert_equal("untouched", outer_e)
+
+// ============================================================
+// Section 32: Exception from recursive function
+// ============================================================
+
+def recursive_throw(n) {
+  if (n == 0) {
+    throw("bottom")
+  }
+  recursive_throw(n - 1)
+}
+
+try {
+  recursive_throw(5)
+}
+catch(e) {
+  assert_equal("bottom", e)
+}
+
+// ============================================================
+// Section 33: Try/catch in a function body
+// ============================================================
+
+def safe_divide(a, b) {
+  try {
+    if (b == 0) {
+      throw("division by zero")
+    }
+    return a / b
+  }
+  catch(e) {
+    return e
+  }
+}
+
+assert_equal(5, safe_divide(10, 2))
+assert_equal("division by zero", safe_divide(10, 0))
+
+// ============================================================
+// Section 34: Throw from [] on a Map with missing key
+// ============================================================
+
+auto s34_caught = false
+try {
+  auto m = ["a": 1]
+  auto x = m["nonexistent"]
+}
+catch(e) {
+  s34_caught = true
+}
+assert_true(s34_caught)
+
+// ============================================================
+// Section 35: Arithmetic exception (divide by zero)
+// ============================================================
+
+auto s35_caught = false
+try {
+  auto x = 1 / 0
+}
+catch(e) {
+  s35_caught = true
+}
+assert_true(s35_caught)

unittests/function_introspection.chai

@@ -39,14 +39,15 @@ assert_equal(true, test_fun_types[1].bare_equal(int_type));
 
 assert_equal(2, `==`.get_arity());
 
-// < should be the merging of two functions bool <(PODObject, PODObject) and bool <(string, string)
+// < should be the merging of three functions bool <(PODObject, PODObject),
+// bool <(string, string), and bool <(string_view, string_view)
 // we want to peel it apart and make sure that's true
 auto types = `<`.get_param_types();
 assert_equal(3, types.size());
 assert_equal(true, types[0].bare_equal(bool_type));
 assert_equal(true, types[1].bare_equal(Object_type));
 assert_equal(true, types[2].bare_equal(Object_type));
-assert_equal(2, `<`.get_contained_functions().size());
+assert_equal(3, `<`.get_contained_functions().size());
 
 
 // guard existence tests

unittests/grammar_constructs.chai

@@ -0,0 +1,219 @@
+// Regression test: exercises grammar constructs documented in grammar/chaiscript.ebnf
+
+// --- Variable declarations ---
+var a = 1
+auto b = 2
+global c = 3
+const d = 42
+
+assert_equal(1, a)
+assert_equal(2, b)
+assert_equal(3, c)
+assert_equal(42, d)
+
+// --- Reference variables ---
+var orig = 10
+var &ref = orig
+ref = 20
+assert_equal(20, orig)
+
+// --- Numeric literals ---
+assert_equal(255, 0xFF)
+assert_equal(255, 0xff)
+assert_equal(5, 0b101)
+assert_equal(42, 42)
+assert_equal(3.14, 3.14)
+
+// --- String interpolation ---
+var name = "world"
+assert_equal("hello world", "hello ${name}")
+
+// --- Escape sequences ---
+assert_equal("\n", "\n")
+assert_equal("\t", "\t")
+
+// --- Single-quoted char ---
+assert_equal('A', 'A')
+
+// --- Operators and precedence ---
+assert_equal(7, 1 + 2 * 3)
+assert_equal(true, 5 > 3 && 2 < 4)
+assert_equal(true, false || true)
+assert_equal(6, 3 << 1)
+assert_equal(1, 3 >> 1)
+assert_equal(5, 7 & 5)
+assert_equal(7, 5 | 3)
+assert_equal(6, 5 ^ 3)
+assert_equal(-1, ~0)
+
+// --- Ternary operator ---
+assert_equal("yes", true ? "yes" : "no")
+assert_equal("no", false ? "yes" : "no")
+
+// --- Prefix operators ---
+var x = 5
+++x
+assert_equal(6, x)
+--x
+assert_equal(5, x)
+assert_equal(true, !false)
+
+// --- Assignment operators ---
+var v = 10
+v += 5; assert_equal(15, v)
+v -= 3; assert_equal(12, v)
+v *= 2; assert_equal(24, v)
+v /= 4; assert_equal(6, v)
+v %= 4; assert_equal(2, v)
+v <<= 2; assert_equal(8, v)
+v >>= 1; assert_equal(4, v)
+v |= 3; assert_equal(7, v)
+v &= 5; assert_equal(5, v)
+v ^= 3; assert_equal(6, v)
+
+// --- Lambda ---
+var add = fun(a, b) { a + b }
+assert_equal(5, add(2, 3))
+
+// --- Lambda with capture ---
+var captured = 100
+var get_captured = fun[captured]() { captured }
+assert_equal(100, get_captured())
+
+// --- Function definition ---
+def multiply(a, b) { a * b }
+assert_equal(12, multiply(3, 4))
+
+// --- Guard condition on function ---
+def abs_val(x) : x >= 0 { x }
+def abs_val(x) : x < 0 { -x }
+assert_equal(5, abs_val(5))
+assert_equal(5, abs_val(-5))
+
+// --- Class definition ---
+class Animal
+{
+  attr sound
+  def Animal(s) { this.sound = s }
+  def speak() { this.sound }
+}
+
+var dog = Animal("woof")
+assert_equal("woof", dog.speak())
+
+// --- Class with inheritance ---
+class Puppy : Animal
+{
+  attr name
+  def Puppy(n, s) { this.name = n; this.sound = s }
+  def greet() { to_string(this.name) + " says " + to_string(this.speak()) }
+}
+
+var p = Puppy("Rex", "yip")
+assert_equal("Rex says yip", p.greet())
+
+// --- Control flow: if/else ---
+var result = ""
+if (true) { result = "yes" } else { result = "no" }
+assert_equal("yes", result)
+
+// --- Control flow: while ---
+var counter = 0
+while (counter < 3) { ++counter }
+assert_equal(3, counter)
+
+// --- Control flow: for ---
+var sum = 0
+for (var i = 0; i < 5; ++i) { sum += i }
+assert_equal(10, sum)
+
+// --- Control flow: ranged for ---
+var items = [10, 20, 30]
+var total = 0
+for (item : items) { total += item }
+assert_equal(60, total)
+
+// --- Switch/case ---
+def classify(n) {
+  var label = ""
+  switch (n) {
+    case (1) { label = "one"; break }
+    case (2) { label = "two"; break }
+    default { label = "other" }
+  }
+  return label
+}
+assert_equal("one", classify(1))
+assert_equal("two", classify(2))
+assert_equal("other", classify(99))
+
+// --- Try/catch/finally ---
+var caught = false
+var finalized = false
+try {
+  throw("oops")
+} catch (e) {
+  caught = true
+} finally {
+  finalized = true
+}
+assert_true(caught)
+assert_true(finalized)
+
+// --- Inline containers ---
+var vec = [1, 2, 3]
+assert_equal(3, vec.size())
+
+var m = ["a": 1, "b": 2]
+assert_equal(1, m["a"])
+
+var r = [1, 2, 3, 4, 5]
+assert_equal(5, r.size())
+
+// --- Dot access chaining ---
+assert_equal(3, [1, 2, 3].size())
+
+// --- Array access ---
+var arr = [10, 20, 30]
+assert_equal(20, arr[1])
+
+// --- Backtick identifier ---
+var `my var` = 42
+assert_equal(42, `my var`)
+
+// --- Special identifiers ---
+assert_equal(true, true)
+assert_equal(false, false)
+
+// --- Nested block ---
+var block_result = 0
+{ block_result = 42 }
+assert_equal(42, block_result)
+
+// --- Break and continue ---
+var break_sum = 0
+for (var i = 0; i < 10; ++i) {
+  if (i == 5) { break }
+  break_sum += i
+}
+assert_equal(10, break_sum)
+
+var cont_sum = 0
+for (var i = 0; i < 5; ++i) {
+  if (i == 2) { continue }
+  cont_sum += i
+}
+assert_equal(8, cont_sum)
+
+// --- Return from function ---
+def early_return(n) {
+  if (n > 0) { return "positive" }
+  return "non-positive"
+}
+assert_equal("positive", early_return(1))
+assert_equal("non-positive", early_return(-1))
+
+// --- Colon assignment ---
+var ca = 0
+ca := 99
+assert_equal(99, ca)

unittests/index_operator_override.chai

@@ -0,0 +1,45 @@
+
+// Test overriding [] operator with various index types (issue #398)
+
+class my_class
+{
+  def my_class()
+  {
+  }
+};
+
+def `[]`(my_class o, idx)
+{
+  return "Hello World!";
+}
+
+var o = my_class();
+
+// Integer index should work
+assert_equal("Hello World!", o[3]);
+
+// String index should work
+assert_equal("Hello World!", o["3"]);
+
+// String variable as index should work
+var s = "abc";
+assert_equal("Hello World!", o[s]);
+
+// Typed string parameter override
+class my_class2
+{
+  def my_class2()
+  {
+  }
+};
+
+def `[]`(my_class2 o, string key)
+{
+  return "key=" + key;
+}
+
+var o2 = my_class2();
+assert_equal("key=foo", o2["foo"]);
+
+var key = "bar";
+assert_equal("key=bar", o2[key]);

unittests/map_find.chai

@@ -0,0 +1,15 @@
+
+auto m = ["k":"v"]
+
+// find existing key returns the value
+assert_equal("v", m.find("k"))
+
+// find missing key returns undef
+assert_true(m.find("missing").is_var_undef())
+
+// find does not mutate the map
+m.find("other")
+assert_equal(1, m.size())
+
+// find works with in-place map
+assert_equal("v", ["k":"v"].find("k"))

unittests/map_keys_vector_push_back.chai

@@ -0,0 +1,29 @@
+// Regression test for issue #594
+// Map keys pushed into a vector via .first should remain valid
+// after the map goes out of scope.
+
+def keys(Map map)
+{
+  var v = Vector();
+  for( i : map )
+  {
+    v.push_back(i.first);
+  }
+  return v;
+}
+
+var k = Vector();
+if ( true )
+{
+  var m = ["a":"x", "b":"y", "c":"z"];
+  k = keys(m);
+}
+
+// After the map is out of scope, the keys should still be valid strings
+assert_equal(3, k.size())
+
+// Verify each element is a non-empty string
+for (elem : k)
+{
+  assert_true(elem.size() > 0)
+}

unittests/modulo_by_zero_protection.chai

@@ -0,0 +1,16 @@
+// modulo by zero should throw, not crash
+try {
+  3 % 0
+  assert_true(false)
+} catch (e) {
+  assert_equal("Arithmetic error: divide by zero", e.what())
+}
+
+// assign-modulo by zero should also throw
+var x = 3;
+try {
+  x %= 0
+  assert_true(false)
+} catch (e) {
+  assert_equal("Arithmetic error: divide by zero", e.what())
+}

unittests/multifile_test_chai.cpp

@@ -5,8 +5,8 @@
 
 Multi_Test_Chai::Multi_Test_Chai()
     : m_chai(new chaiscript::ChaiScript_Basic(
-        chaiscript::Std_Lib::library(),
-        std::make_unique<chaiscript::parser::ChaiScript_Parser<chaiscript::eval::Noop_Tracer, chaiscript::optimizer::Optimizer_Default>>())) {
+          chaiscript::Std_Lib::library(),
+          std::make_unique<chaiscript::parser::ChaiScript_Parser<chaiscript::eval::Noop_Tracer, chaiscript::optimizer::Optimizer_Default>>())) {
 }
 
 std::shared_ptr<chaiscript::ChaiScript_Basic> Multi_Test_Chai::get_chai() {

unittests/nested_namespaces.chai

@@ -0,0 +1,55 @@
+// Test C++-style block namespace declarations
+namespace constants::si {
+  def mu_B() { return 1.0 }
+}
+
+namespace constants::mm {
+  def mu_B() { return 2.0 }
+}
+
+assert_equal(1.0, constants::si::mu_B())
+assert_equal(2.0, constants::mm::mu_B())
+
+// Test deeper nesting with block syntax
+namespace a::b::c {
+  def val() { return 42 }
+}
+
+assert_equal(42, a::b::c::val())
+
+// Test reopening a namespace to add more members
+namespace math {
+  def square(x) { x * x }
+}
+
+namespace math::trig {
+  def double_angle(x) { 2.0 * x }
+}
+
+assert_equal(16, math::square(4))
+assert_equal(6.0, math::trig::double_angle(3.0))
+
+// Test reopening a namespace (C++ allows this)
+namespace math {
+  def cube(x) { x * x * x }
+}
+
+assert_equal(27, math::cube(3))
+
+// Test that :: scope resolution works the same as . for access
+assert_equal(16, math.square(4))
+assert_equal(6.0, math.trig.double_angle(3.0))
+
+// Test namespace with var declarations
+namespace config {
+  var pi = 3.14159
+  var name = "test"
+}
+
+assert_equal(3.14159, config::pi)
+assert_equal("test", config::name)
+
+// Test function-call style still works
+namespace("compat")
+compat.legacy = 99
+assert_equal(99, compat::legacy)

unittests/object_from_json_1.chai

@@ -0,0 +1,6 @@
+// object_from_json: returns Dynamic_Object with dot-access on JSON fields
+var obj = object_from_json("{\"name\":\"ChaiScript\",\"version\":6,\"active\":true}")
+assert_equal(obj.name, "ChaiScript")
+assert_equal(obj.version, 6)
+assert_equal(obj.active, true)
+assert_equal(obj.get_type_name(), "JSON_Object")

unittests/object_from_json_2.chai

@@ -0,0 +1,3 @@
+// object_from_json: nested objects become nested Dynamic_Objects
+var obj = object_from_json("{\"outer\":{\"inner\":42}}")
+assert_equal(obj.outer.inner, 42)

unittests/object_from_json_3.chai

@@ -0,0 +1,3 @@
+// object_from_json: arrays remain as vectors
+var obj = object_from_json("{\"items\":[1,2,3]}")
+assert_equal(obj.items, [1,2,3])

unittests/object_from_json_4.chai

@@ -0,0 +1,9 @@
+// object_to_map and map_to_object conversions
+var m = ["a": 1, "b": "hello"]
+var obj = map_to_object(m)
+assert_equal(obj.a, 1)
+assert_equal(obj.b, "hello")
+
+var m2 = object_to_map(obj)
+assert_equal(m2["a"], 1)
+assert_equal(m2["b"], "hello")

unittests/object_from_json_5.chai

@@ -0,0 +1,6 @@
+// object_from_json roundtrip through to_json
+var json_str = "{\"key\":\"value\"}"
+var obj = object_from_json(json_str)
+var result = to_json(obj)
+var obj2 = object_from_json(result)
+assert_equal(obj2.key, "value")

unittests/recursion_depth_protection.chai

@@ -0,0 +1,41 @@
+// Regression test for issue #633: Stack-overflow due to infinite recursion
+// in user-defined operator (string interpolation).
+//
+// Before the fix the recursive `/=` invocation triggered unbounded native
+// recursion in the evaluator and crashed the host process with a SIGSEGV.
+// The engine now bounds call_depth and throws a catchable exception
+// instead of letting the native stack overflow.
+
+def string::`/=`(double d) {
+  this = "${this/= 2}/=${d}";
+  return this;
+}
+
+var s = "o World"
+var caught = false
+var message = ""
+
+try {
+  s /= 2
+  // unreachable: the recursive operator must abort with an exception
+  assert_true(false)
+} catch (e) {
+  caught = true
+  message = e.what()
+}
+
+assert_true(caught)
+
+// The reported error must mention the call-stack overflow so users can
+// distinguish it from an arbitrary script-level error.
+assert_true(find(message, "call stack") != -1)
+
+// A bounded recursion that stays well below the limit must keep working.
+// Use a small depth so the test passes on every platform default - notably
+// the MSVC Debug build where the native stack budget forces a tighter cap.
+def count_down(n) {
+  if (n <= 0) { return 0 }
+  return count_down(n - 1) + 1
+}
+
+assert_equal(10, count_down(10))

unittests/return_assignment.chai

@@ -0,0 +1,16 @@
+// Test that assignment expressions work inside return statements
+// Issue #473: `return foo = 5` should work
+
+def return_assign() {
+  var x = 0
+  return x = 5
+}
+
+assert_equal(5, return_assign())
+
+def return_member_assign() {
+  var o = Dynamic_Object()
+  return o.value = 42
+}
+
+assert_equal(42, return_member_assign())

unittests/strong_typedef.chai

@@ -0,0 +1,200 @@
+// Strong typedef: using Type = int creates a distinct type
+using Meters = int
+
+def measure(Meters m) {
+  return m
+}
+
+// Constructing a strong typedef value should work
+var m = Meters(42)
+
+// Calling with the typedef'd value should succeed
+measure(m)
+
+// Calling with a plain int should fail (strong typedef)
+try {
+  measure(42)
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: type mismatch because int is not Meters
+}
+
+// Multiple strong typedefs from the same base type should be distinct
+using Seconds = int
+
+def wait(Seconds s) {
+  return s
+}
+
+var s = Seconds(10)
+wait(s)
+
+// Meters and Seconds should not be interchangeable
+try {
+  wait(m)
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: Meters is not Seconds
+}
+
+try {
+  measure(s)
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: Seconds is not Meters
+}
+
+// to_underlying should return the base value
+assert_equal(to_underlying(m), 42)
+assert_equal(to_underlying(s), 10)
+
+// to_underlying result should be a plain value, not a strong typedef
+def takes_int(int i) {
+  return i
+}
+assert_equal(takes_int(to_underlying(m)), 42)
+
+// --- Arithmetic operators: strongly typed ---
+var m2 = Meters(8)
+var m_sum = m + m2
+assert_equal(to_underlying(m_sum), 50)
+measure(m_sum)
+
+var m_diff = m - m2
+assert_equal(to_underlying(m_diff), 34)
+
+var m_prod = Meters(3) * Meters(4)
+assert_equal(to_underlying(m_prod), 12)
+
+var m_quot = Meters(20) / Meters(5)
+assert_equal(to_underlying(m_quot), 4)
+
+var m_rem = Meters(17) % Meters(5)
+assert_equal(to_underlying(m_rem), 2)
+
+// Arithmetic result is strongly typed, not plain int
+try {
+  takes_int(m_sum)
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: m_sum is Meters, not int
+}
+
+// --- Comparison operators ---
+assert_equal(Meters(5) == Meters(5), true)
+assert_equal(Meters(5) != Meters(3), true)
+assert_equal(Meters(3) < Meters(5), true)
+assert_equal(Meters(5) > Meters(3), true)
+assert_equal(Meters(5) <= Meters(5), true)
+assert_equal(Meters(3) >= Meters(3), true)
+assert_equal(Meters(3) >= Meters(5), false)
+
+// --- Bitwise and shift operators ---
+assert_equal(to_underlying(Meters(6) & Meters(3)), 2)
+assert_equal(to_underlying(Meters(6) | Meters(3)), 7)
+assert_equal(to_underlying(Meters(6) ^ Meters(3)), 5)
+assert_equal(to_underlying(Meters(5) << Meters(2)), 20)
+assert_equal(to_underlying(Meters(12) >> Meters(1)), 6)
+
+// Bitwise results are strongly typed
+try {
+  takes_int(Meters(6) & Meters(3))
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: result is Meters, not int
+}
+
+// --- Strong typedef over string ---
+using StrongString = string
+
+var ss1 = StrongString("hello")
+var ss2 = StrongString(" world")
+var ss_cat = ss1 + ss2
+assert_equal(to_underlying(ss_cat), "hello world")
+
+// StrongString + StrongString -> StrongString (strongly typed)
+def takes_strong_string(StrongString ss) {
+  return ss
+}
+takes_strong_string(ss_cat)
+
+// Operators not supported by the underlying type error at call time
+try {
+  var bad = ss1 * ss2
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: underlying string has no * operator
+}
+try {
+  var bad = ss1 - ss2
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: underlying string has no - operator
+}
+try {
+  var bad = ss1 / ss2
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: underlying string has no / operator
+}
+try {
+  var bad = ss1 % ss2
+  assert_equal(true, false)
+} catch(e) {
+  // Expected: underlying string has no % operator
+}
+
+// Comparison on StrongString
+assert_equal(StrongString("abc") < StrongString("def"), true)
+assert_equal(StrongString("abc") == StrongString("abc"), true)
+assert_equal(StrongString("abc") != StrongString("def"), true)
+assert_equal(StrongString("def") > StrongString("abc"), true)
+assert_equal(StrongString("abc") <= StrongString("abc"), true)
+assert_equal(StrongString("def") >= StrongString("abc"), true)
+
+// --- User-defined extensions on strong typedefs ---
+def first_char(StrongString ss) {
+  return to_string(to_underlying(ss)[0])
+}
+assert_equal(first_char(StrongString("hello")), "h")
+
+def double_meters(Meters m) {
+  return Meters(to_underlying(m) * 2)
+}
+assert_equal(to_underlying(double_meters(Meters(21))), 42)
+
+// User-defined operator extension
+def `[]`(StrongString ss, int offset) {
+  return to_string(to_underlying(ss)[offset])
+}
+assert_equal(StrongString("hello")[1], "e")
+
+// --- Compound assignment operators ---
+var m3 = Meters(10)
+m3 += Meters(5)
+assert_equal(to_underlying(m3), 15)
+measure(m3)
+
+m3 -= Meters(3)
+assert_equal(to_underlying(m3), 12)
+
+m3 *= Meters(2)
+assert_equal(to_underlying(m3), 24)
+
+m3 /= Meters(4)
+assert_equal(to_underlying(m3), 6)
+
+m3 %= Meters(4)
+assert_equal(to_underlying(m3), 2)
+
+// Compound assignment result is still the strong typedef
+var m4 = Meters(10)
+m4 += Meters(5)
+assert_equal(to_underlying(m4), 15)
+measure(m4)
+
+// Compound assignment on StrongString
+var ss3 = StrongString("hello")
+ss3 += StrongString(" world")
+assert_equal(to_underlying(ss3), "hello world")
+takes_strong_string(ss3)

unittests/threading_config_test.cpp

@@ -0,0 +1,26 @@
+#include <chaiscript/chaiscript.hpp>
+
+int main() {
+#ifndef CHAISCRIPT_NO_THREADS
+  // When threading is enabled, verify that async() is registered and functional
+  chaiscript::ChaiScript chai;
+  const auto result = chai.eval<int>(R"(
+    var f = async(fun() { return 42; });
+    f.get();
+  )");
+  if (result != 42) {
+    return EXIT_FAILURE;
+  }
+#else
+  // When threading is disabled, verify that async() is NOT registered
+  chaiscript::ChaiScript chai;
+  try {
+    chai.eval("async(fun() { return 0; })");
+    return EXIT_FAILURE;
+  } catch (const std::exception &) {
+    // Expected: async should not exist
+  }
+#endif
+
+  return EXIT_SUCCESS;
+}

unittests/type_info_test.cpp

@@ -16,9 +16,7 @@
 #include <cstdlib>
 #include <iostream>
 
-#define CATCH_CONFIG_MAIN
-
-#include "catch.hpp"
+#include "catch_amalgamated.hpp"
 
 TEST_CASE("Type_Info objects generate expected results") {
   const auto test_type