refactor(metadata): integrate Boost.Describe to remove manual mapping boilerplate

This introduces Boost.Describe and Boost.Mp11 and applies them across
metadata types (symbols, enums, inline elements) to replace hand-written
io.map() calls with reflection-based code. This improves maintainability
without altering the public API or user-facing features.

Boost.Describe and Boost.Mp11 are *private* dependencies, i.e. they are
not used in any public Mr. Docs include.

Author: gennaroprota

.github/workflows/ci.yml

@@ -433,6 +433,44 @@ jobs:
         run: |
           rm -r ../third-party/llvm-project
 
+      - name: Install Boost.Mp11
+        uses: alandefreitas/cpp-actions/cmake-workflow@v1.8.12
+        with:
+          source-dir: ../third-party/boost_mp11
+          git-repository: https://github.com/boostorg/mp11
+          git-tag: boost-1.90.0
+          patches: |
+            ./third-party/patches/boost_mp11/CMakeLists.txt
+            ./third-party/patches/boost_mp11/boost_mp11-config.cmake.in
+          build-dir: ${sourceDir}/build
+          cc: ${{ steps.setup-cpp.outputs.cc }}
+          cxx: ${{ steps.setup-cpp.outputs.cxx }}
+          build-type: Release
+          shared: false
+          install: true
+          install-prefix: ${sourceDir}/install
+          run-tests: false
+          trace-commands: true
+
+      - name: Install Boost.Describe
+        uses: alandefreitas/cpp-actions/cmake-workflow@v1.8.12
+        with:
+          source-dir: ../third-party/boost_describe
+          git-repository: https://github.com/boostorg/describe
+          git-tag: boost-1.90.0
+          patches: |
+            ./third-party/patches/boost_describe/CMakeLists.txt
+            ./third-party/patches/boost_describe/boost_describe-config.cmake.in
+          build-dir: ${sourceDir}/build
+          cc: ${{ steps.setup-cpp.outputs.cc }}
+          cxx: ${{ steps.setup-cpp.outputs.cxx }}
+          build-type: Release
+          shared: false
+          install: true
+          install-prefix: ${sourceDir}/install
+          run-tests: false
+          trace-commands: true
+
       - name: Install JerryScript
         uses: alandefreitas/cpp-actions/cmake-workflow@v1.9.2
         with:
@@ -567,6 +605,8 @@ jobs:
             -D LUA_ROOT="${{ steps.rmatrix.outputs.third-party-dir }}/lua/install"
             -D Lua_ROOT="${{ steps.rmatrix.outputs.third-party-dir }}/lua/install"
             -D lua_ROOT="${{ steps.rmatrix.outputs.third-party-dir }}/lua/install"
+            -D boost_mp11_ROOT="${{ steps.rmatrix.outputs.third-party-dir }}/boost_mp11/install"
+            -D boost_describe_ROOT="${{ steps.rmatrix.outputs.third-party-dir }}/boost_describe/install"
             ${{ runner.os == 'Windows' && '-D LibXml2_ROOT=../third-party/libxml2/install' || '' }}
           export-compile-commands: true
           run-tests: true

CMakeLists.txt

@@ -223,6 +223,10 @@ endif()
 
 set(CMAKE_FOLDER Dependencies)
 
+# Boost.Describe + Boost.Mp11 (header-only, fetched via bootstrap.py recipes)
+find_package(boost_mp11 REQUIRED)
+find_package(boost_describe REQUIRED)
+
 # LLVM + Clang
 if (LLVM_ROOT)
     # LLVM_ROOT is absolute
@@ -320,6 +324,7 @@ target_compile_definitions(
     PRIVATE
     -DMRDOCS_TOOL
 )
+target_link_libraries(mrdocs-core PRIVATE Boost::describe Boost::mp11)
 
 # Dependencies
 target_include_directories(mrdocs-core

docs/mrdocs.yml

@@ -13,6 +13,14 @@ implementation-defined:
   - 'mrdocs::detail'
   - 'mrdocs::report::detail'
   - 'mrdocs::dom::detail'
+exclude-symbols:
+    # Symbols defined when using the Boost.Describe macros.
+  - 'mrdocs::**::boost_base_descriptor_fn'
+  - 'mrdocs::**::boost_public_member_descriptor_fn'
+  - 'mrdocs::**::boost_protected_member_descriptor_fn'
+  - 'mrdocs::**::boost_private_member_descriptor_fn'
+  - 'mrdocs::**::boost_enum_descriptor_fn'
+  - 'mrdocs::**::should_use_BOOST_DESCRIBE_NESTED_ENUM'
 multipage: true
 generator: adoc
 cmake: '-D MRDOCS_DOCUMENTATION_BUILD=ON'