Avoid msvc-14.0 constexpr errors in enum_to_string

Extended limit for describe/detail/pp_for_each.hpp from 52 to 64

.drone.jsonnet

@@ -32,7 +32,8 @@ local linux_pipeline(name, image, environment, packages = "", sources = [], arch
             commands:
             [
                 'set -e',
-                'wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -',
+                'uname -a',
+                'echo $DRONE_STAGE_MACHINE',
             ] +
             (if sources != [] then [ ('apt-add-repository "' + source + '"') for source in sources ] else []) +
             (if packages != "" then [ 'apt-get update', 'apt-get -y install ' + packages ] else []) +
@@ -187,12 +188,33 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 23.04 GCC 13",
-        "cppalliance/droneubuntu2304:1",
+        "Linux 24.04 GCC 13",
+        "cppalliance/droneubuntu2404:1",
         { TOOLSET: 'gcc', COMPILER: 'g++-13', CXXSTD: '03,11,14,17,20,2b' },
         "g++-13",
     ),
 
+    linux_pipeline(
+        "Linux 24.04 GCC 14 UBSAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-14', CXXSTD: '03,11,14,17,20,2b' } + ubsan,
+        "g++-14",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 GCC 14 ASAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-14', CXXSTD: '03,11,14,17,20,2b' } + asan,
+        "g++-14",
+    ),
+
+    linux_pipeline(
+        "Linux 25.04 GCC 15",
+        "cppalliance/droneubuntu2504:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-15', CXXSTD: '03,11,14,17,20,23,2c' },
+        "g++-15",
+    ),
+
     linux_pipeline(
         "Linux 16.04 Clang 3.5",
         "cppalliance/droneubuntu1604:1",
@@ -238,7 +260,7 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     linux_pipeline(
         "Linux 18.04 Clang 5.0",
         "cppalliance/droneubuntu1804:1",
-        { TOOLSET: 'clang', COMPILER: 'clang++-5.0', CXXSTD: '03,11,14,1z' },
+        { TOOLSET: 'clang', COMPILER: 'clang++-5.0', CXXSTD: '03,11,14' },
         "clang-5.0",
     ),
 
@@ -313,30 +335,100 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 23.04 Clang 16",
-        "cppalliance/droneubuntu2304:1",
+        "Linux 24.04 Clang 16",
+        "cppalliance/droneubuntu2404:1",
         { TOOLSET: 'clang', COMPILER: 'clang++-16', CXXSTD: '03,11,14,17,20,2b' },
         "clang-16",
     ),
 
     linux_pipeline(
-        "Linux 23.10 Clang 17",
-        "cppalliance/droneubuntu2310:1",
+        "Linux 24.04 Clang 17",
+        "cppalliance/droneubuntu2404:1",
         { TOOLSET: 'clang', COMPILER: 'clang++-17', CXXSTD: '03,11,14,17,20,2b' },
         "clang-17",
     ),
 
-    macos_pipeline(
-        "MacOS 10.15 Xcode 12.2",
-        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' },
+    linux_pipeline(
+        "Linux 24.04 Clang 18 UBSAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-18', CXXSTD: '03,11,14,17,20,2b' } + ubsan,
+        "clang-18",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 Clang 18 ASAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-18', CXXSTD: '03,11,14,17,20,2b' } + asan,
+        "clang-18",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 Clang 19",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-19', CXXSTD: '03,11,14,17,20,2b' },
+        "clang-19",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 Clang 20",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-20', CXXSTD: '03,11,14,17,20,23,2c' },
+        "clang-20",
+    ),
+
+    linux_pipeline(
+        "Linux 25.10 Clang 21",
+        "cppalliance/droneubuntu2510:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-21', CXXSTD: '03,11,14,17,20,23,2c' },
+        "clang-21",
     ),
 
     macos_pipeline(
-        "MacOS 12.4 Xcode 13.4.1",
-        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' },
+        "MacOS 10.15 Xcode 12.2 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + ubsan,
+    ),
+
+    macos_pipeline(
+        "MacOS 10.15 Xcode 12.2 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + asan,
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.2.1 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + ubsan,
+        xcode_version = "13.2.1", osx_version = "monterey", arch = "arm64",
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.2.1 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + asan,
+        xcode_version = "13.2.1", osx_version = "monterey", arch = "arm64",
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.4.1 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + ubsan,
         xcode_version = "13.4.1", osx_version = "monterey", arch = "arm64",
     ),
 
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.4.1 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + asan,
+        xcode_version = "13.4.1", osx_version = "monterey", arch = "arm64",
+    ),
+
+    macos_pipeline(
+        "MacOS 14 Xcode 16.2.0 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + ubsan,
+        xcode_version = "16.2.0", osx_version = "sonoma", arch = "arm64",
+    ),
+
+    macos_pipeline(
+        "MacOS 14 Xcode 16.2.0 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + asan,
+        xcode_version = "16.2.0", osx_version = "sonoma", arch = "arm64",
+    ),
+
     windows_pipeline(
         "Windows VS2015 msvc-14.0",
         "cppalliance/dronevs2015",

.github/workflows/ci.yml

@@ -19,30 +19,33 @@ jobs:
         include:
           - toolset: gcc-4.8
             cxxstd: "03,11"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: g++-4.8
           - toolset: gcc-5
             cxxstd: "03,11,14,14-gnu,1z,1z-gnu"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: g++-5
           - toolset: gcc-6
             cxxstd: "03,11,14,14-gnu,1z,1z-gnu"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: g++-6
           - toolset: gcc-7
             cxxstd: "03,11,14,14-gnu,17,17-gnu"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: g++-7
           - toolset: gcc-8
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: g++-8
           - toolset: gcc-9
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
           - toolset: gcc-10
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-22.04
@@ -56,61 +59,78 @@ jobs:
             install: g++-12
           - toolset: gcc-13
             cxxstd: "03,11,14,17,20,2b"
+            container: ubuntu:24.04
             os: ubuntu-latest
-            container: ubuntu:23.04
             install: g++-13
+          - toolset: gcc-14
+            cxxstd: "03,11,14,17,20,2b"
+            container: ubuntu:24.04
+            os: ubuntu-latest
+            install: g++-14
+          - toolset: gcc-15
+            cxxstd: "03,11,14,17,20,23,2c"
+            container: ubuntu:25.10
+            os: ubuntu-latest
+            install: g++-15
           - toolset: clang
             compiler: clang++-3.9
             cxxstd: "03,11,14"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: clang-3.9
           - toolset: clang
             compiler: clang++-4.0
             cxxstd: "03,11,14"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: clang-4.0
           - toolset: clang
             compiler: clang++-5.0
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-latest
+            cxxstd: "03,11,14"
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: clang-5.0
           - toolset: clang
             compiler: clang++-6.0
             cxxstd: "03,11,14,17"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-6.0
           - toolset: clang
             compiler: clang++-7
             cxxstd: "03,11,14,17"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-7
           - toolset: clang
             compiler: clang++-8
             cxxstd: "03,11,14,17"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-8
           - toolset: clang
             compiler: clang++-9
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-9
           - toolset: clang
             compiler: clang++-10
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-10
           - toolset: clang
             compiler: clang++-11
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-11
           - toolset: clang
             compiler: clang++-12
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-12
           - toolset: clang
             compiler: clang++-13
@@ -133,40 +153,76 @@ jobs:
           - toolset: clang
             compiler: clang++-16
             cxxstd: "03,11,14,17,20,2b"
-            container: ubuntu:23.04
+            container: ubuntu:24.04
             os: ubuntu-latest
             install: clang-16
           - toolset: clang
             compiler: clang++-17
             cxxstd: "03,11,14,17,20,2b"
-            container: ubuntu:23.10
+            container: ubuntu:24.04
             os: ubuntu-latest
             install: clang-17
           - toolset: clang
-            cxxstd: "03,11,14,17,2a"
-            os: macos-11
+            compiler: clang++-18
+            cxxstd: "03,11,14,17,20,2b"
+            container: ubuntu:24.04
+            os: ubuntu-latest
+            install: clang-18
+          - toolset: clang
+            compiler: clang++-19
+            cxxstd: "03,11,14,17,20,2b"
+            container: ubuntu:24.04
+            os: ubuntu-latest
+            install: clang-19
+          - toolset: clang
+            compiler: clang++-20
+            cxxstd: "03,11,14,17,20,23,2c"
+            container: ubuntu:24.04
+            os: ubuntu-latest
+            install: clang-20
+          - toolset: clang
+            compiler: clang++-21
+            cxxstd: "03,11,14,17,20,23,2c"
+            container: ubuntu:25.10
+            os: ubuntu-latest
+            install: clang-21
           - toolset: clang
             cxxstd: "03,11,14,17,20,2b"
-            os: macos-12
+            os: macos-14
           - toolset: clang
             cxxstd: "03,11,14,17,20,2b"
-            os: macos-13
+            os: macos-15
+          - toolset: clang
+            cxxstd: "03,11,14,17,20,23,2c"
+            os: macos-26
 
     runs-on: ${{matrix.os}}
-    container: ${{matrix.container}}
+
+    container:
+      image: ${{matrix.container}}
+      volumes:
+        - /node20217:/node20217:rw,rshared
+        - ${{ startsWith(matrix.container, 'ubuntu:1') && '/node20217:/__e/node20:ro,rshared' || ' ' }}
 
     defaults:
       run:
         shell: bash
 
     steps:
-      - uses: actions/checkout@v3
-
       - name: Setup container environment
         if: matrix.container
         run: |
           apt-get update
-          apt-get -y install sudo python3 git g++
+          apt-get -y install sudo python3 git g++ curl xz-utils
+
+      - name: Install nodejs20glibc2.17
+        if: ${{ startsWith( matrix.container, 'ubuntu:1' ) }}
+        run: |
+          curl -LO https://archives.boost.io/misc/node/node-v20.9.0-linux-x64-glibc-217.tar.xz
+          tar -xf node-v20.9.0-linux-x64-glibc-217.tar.xz --strip-components 1 -C /node20217
+          ldd /__e/node20/bin/node
+
+      - uses: actions/checkout@v4
 
       - name: Install packages
         if: matrix.install
@@ -212,19 +268,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - toolset: msvc-14.0
-            cxxstd: "14,latest"
-            addrmd: 32,64
-            os: windows-2019
-          - toolset: msvc-14.2
-            cxxstd: "14,17,20,latest"
-            addrmd: 32,64
-            os: windows-2019
-          - toolset: msvc-14.2
-            cxxstd: "14,17,20,latest"
-            addrmd: 32,64
-            cxxflags: "-Zc:preprocessor"
-            os: windows-2019
           - toolset: msvc-14.3
             cxxstd: "14,17,20,latest"
             addrmd: 32,64
@@ -241,12 +284,12 @@ jobs:
           - toolset: gcc
             cxxstd: "03,11,14,17,2a"
             addrmd: 64
-            os: windows-2019
+            os: windows-2022
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup Boost
         shell: cmd
@@ -282,16 +325,16 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-11
-          - os: macos-12
-          - os: macos-13
+          - os: ubuntu-24.04
+          - os: macos-14
+          - os: macos-15
+          - os: macos-26
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install packages
         if: matrix.install
@@ -330,16 +373,16 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-11
-          - os: macos-12
-          - os: macos-13
+          - os: ubuntu-24.04
+          - os: macos-14
+          - os: macos-15
+          - os: macos-26
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install packages
         if: matrix.install
@@ -388,16 +431,16 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-11
-          - os: macos-12
-          - os: macos-13
+          - os: ubuntu-24.04
+          - os: macos-14
+          - os: macos-15
+          - os: macos-26
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install packages
         if: matrix.install
@@ -444,13 +487,12 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: windows-2019
-          - os: windows-2022
+          - os: windows-latest
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup Boost
         shell: cmd
@@ -493,13 +535,12 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: windows-2019
-          - os: windows-2022
+          - os: windows-latest
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup Boost
         shell: cmd
@@ -560,13 +601,12 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: windows-2019
-          - os: windows-2022
+          - os: windows-latest
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup Boost
         shell: cmd

appveyor.yml

@@ -24,9 +24,13 @@ environment:
       TOOLSET: msvc-14.1
       CXXSTD: 14,17,latest
       ADDRMD: 32,64
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      TOOLSET: msvc-14.2
+      CXXSTD: 14,17,20,latest
+      ADDRMD: 32,64
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
       TOOLSET: clang-win
-      CXXSTD: 14,17,latest
+      CXXSTD: 14,17,20,latest
       ADDRMD: 32,64
 
 install:

build.jam

@@ -0,0 +1,20 @@
+# Copyright 2023-2024 René Ferdinand Rivera Morell
+# Copyright 2024 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+require-b2 5.2 ;
+
+constant boost_dependencies :
+    /boost/mp11//boost_mp11
+    ;
+
+project /boost/describe ;
+
+explicit
+    [ alias boost_describe : : : : <include>include <library>$(boost_dependencies) ]
+    [ alias all : boost_describe test ]
+    ;
+
+call-if : boost-library describe
+    ;

doc/describe/changes.adoc

@@ -8,6 +8,11 @@ https://www.boost.org/LICENSE_1_0.txt
 # Revision History
 :idprefix:
 
+## Changes in Boost 1.91.0
+
+* Under {cpp}20, described nested enums now work when the enclosing class is still incomplete. (Thanks to Julien Blanc.)
+* Made `enum_to_string` constexpr. (Thanks to Julien Blanc.)
+
 ## Changes in Boost 1.84.0
 
 * Added an overload of `enum_from_string` that takes a string view, to avoid

doc/describe/examples.adoc

@@ -263,6 +263,11 @@ The presence of private members is taken as an indication that
 a universal conversion is not suitable, so the overload is
 disabled in this case using `std::enable_if_t`.
 
+NOTE: Since release 1.81.0, Boost.JSON provides its
+own, built-in, support for described classes. Consequently,
+when using Boost 1.81.0 or later, you don't need the below
+`tag_invoke` function.
+
 [source]
 ----
 include::../../example/to_json.cpp[lines=5..-1]
@@ -282,6 +287,11 @@ Like the previous example, but in the other direction. Defines
 a `tag_invoke` overload that converts a `boost::json::value` to
 an annotated struct.
 
+NOTE: Since release 1.81.0, Boost.JSON provides its
+own, built-in, support for described classes. Consequently,
+when using Boost 1.81.0 or later, you don't need the below
+`tag_invoke` function.
+
 [source]
 ----
 include::../../example/from_json.cpp[lines=5..-1]

example/from_json.cpp

@@ -5,11 +5,14 @@
 #include <boost/describe.hpp>
 #include <boost/mp11.hpp>
 #include <boost/json.hpp>
+#include <boost/version.hpp>
 #include <type_traits>
 
 namespace app
 {
 
+#if BOOST_VERSION < 108100
+
 template<class T> void extract( boost::json::object const & obj, char const * name, T & value )
 {
     value = boost::json::value_to<T>( obj.at( name ) );
@@ -36,6 +39,8 @@ template<class T,
     return t;
 }
 
+#endif
+
 struct A
 {
     int x;

example/to_json.cpp

@@ -5,6 +5,7 @@
 #include <boost/describe.hpp>
 #include <boost/mp11.hpp>
 #include <boost/json.hpp>
+#include <boost/version.hpp>
 #include <type_traits>
 #include <vector>
 #include <map>
@@ -12,6 +13,8 @@
 namespace app
 {
 
+#if BOOST_VERSION < 108100
+
 template<class T,
     class D1 = boost::describe::describe_members<T,
         boost::describe::mod_public | boost::describe::mod_protected>,
@@ -29,6 +32,8 @@ template<class T,
     });
 }
 
+#endif
+
 struct A
 {
     int x;

include/boost/describe/detail/bases.hpp

@@ -30,24 +30,18 @@ template<class C, class B> struct base_descriptor
 template<class C, class B> constexpr unsigned base_descriptor<C, B>::modifiers;
 #endif
 
-template<class... T> auto base_descriptor_fn_impl( int, T... )
+// bases_descriptor
+template<typename ...>
+struct bases_descriptor_impl;
+
+template<class C, class ...Bs>
+struct bases_descriptor_impl<C, list<Bs...>>
 {
-    return list<T...>();
-}
-
-#define BOOST_DESCRIBE_BASE_IMPL(C, B) , boost::describe::detail::base_descriptor<C, B>()
-
-#if defined(_MSC_VER) && !defined(__clang__)
+    using type = list<base_descriptor<C, Bs>...>;
+};
 
 #define BOOST_DESCRIBE_BASES(C, ...) inline auto boost_base_descriptor_fn( C** ) \
-{ return boost::describe::detail::base_descriptor_fn_impl( 0 BOOST_DESCRIBE_PP_FOR_EACH(BOOST_DESCRIBE_BASE_IMPL, C, __VA_ARGS__) ); }
-
-#else
-
-#define BOOST_DESCRIBE_BASES(C, ...) inline auto boost_base_descriptor_fn( C** ) \
-{ return boost::describe::detail::base_descriptor_fn_impl( 0 BOOST_DESCRIBE_PP_FOR_EACH(BOOST_DESCRIBE_BASE_IMPL, C, ##__VA_ARGS__) ); }
-
-#endif
+{ return typename boost::describe::detail::bases_descriptor_impl<C, boost::describe::detail::list<__VA_ARGS__>>::type(); }
 
 } // namespace detail
 } // namespace describe

include/boost/describe/detail/config.hpp

@@ -37,4 +37,28 @@
 # define BOOST_DESCRIBE_MAYBE_UNUSED
 #endif
 
+#if defined(__cpp_inline_variables) && __cpp_inline_variables >= 201606L
+# define BOOST_DESCRIBE_INLINE_VARIABLE inline
+#else
+# define BOOST_DESCRIBE_INLINE_VARIABLE
+#endif
+
+#define BOOST_DESCRIBE_INLINE_CONSTEXPR BOOST_DESCRIBE_INLINE_VARIABLE BOOST_DESCRIBE_CONSTEXPR_OR_CONST
+
+#if __cplusplus >= 202002L || ( defined(_MSVC_LANG) && _MSVC_LANG >= 202002L )
+
+# define BOOST_DESCRIBE_CXX20
+
+// Clang 13.0 is needed for unevaluated lambdas
+# if defined(__clang__) && __clang_major__ < 13
+#  undef BOOST_DESCRIBE_CXX20
+# endif
+
+// Apple Clang 13.1 is Clang 13.0
+# if defined(__clang__) && defined(__apple_build_version__) && __clang_major__ == 13 && __clang_minor__ < 1
+#  undef BOOST_DESCRIBE_CXX20
+# endif
+
+#endif
+
 #endif // #ifndef BOOST_DESCRIBE_DETAIL_CONFIG_HPP_INCLUDED

include/boost/describe/detail/pp_for_each.hpp

@@ -60,11 +60,35 @@
 #define BOOST_DESCRIBE_PP_FOR_EACH_50(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_49(F, a, __VA_ARGS__))
 #define BOOST_DESCRIBE_PP_FOR_EACH_51(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_50(F, a, __VA_ARGS__))
 #define BOOST_DESCRIBE_PP_FOR_EACH_52(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_51(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_53(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_52(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_54(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_53(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_55(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_54(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_56(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_55(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_57(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_56(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_58(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_57(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_59(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_58(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_60(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_59(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_61(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_60(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_62(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_61(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_63(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_62(F, a, __VA_ARGS__))
+#define BOOST_DESCRIBE_PP_FOR_EACH_64(F, a, x, ...) BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_CALL(F, a, x) BOOST_DESCRIBE_PP_FOR_EACH_63(F, a, __VA_ARGS__))
 
-#define BOOST_DESCRIBE_PP_FE_EXTRACT(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _52, V, ...) V
+#define BOOST_DESCRIBE_PP_FE_EXTRACT(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _60, _61, _62, _63, _64, V, ...) V
 
 #define BOOST_DESCRIBE_PP_FOR_EACH(F, ...) \
     BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_EXPAND(BOOST_DESCRIBE_PP_FE_EXTRACT(__VA_ARGS__, \
+    BOOST_DESCRIBE_PP_FOR_EACH_64, \
+    BOOST_DESCRIBE_PP_FOR_EACH_63, \
+    BOOST_DESCRIBE_PP_FOR_EACH_62, \
+    BOOST_DESCRIBE_PP_FOR_EACH_61, \
+    BOOST_DESCRIBE_PP_FOR_EACH_60, \
+    BOOST_DESCRIBE_PP_FOR_EACH_59, \
+    BOOST_DESCRIBE_PP_FOR_EACH_58, \
+    BOOST_DESCRIBE_PP_FOR_EACH_57, \
+    BOOST_DESCRIBE_PP_FOR_EACH_56, \
+    BOOST_DESCRIBE_PP_FOR_EACH_55, \
+    BOOST_DESCRIBE_PP_FOR_EACH_54, \
+    BOOST_DESCRIBE_PP_FOR_EACH_53, \
     BOOST_DESCRIBE_PP_FOR_EACH_52, \
     BOOST_DESCRIBE_PP_FOR_EACH_51, \
     BOOST_DESCRIBE_PP_FOR_EACH_50, \

include/boost/describe/enum.hpp

@@ -43,6 +43,23 @@ template<class... T> auto enum_descriptor_fn_impl( int, T... )
     return list<enum_descriptor<T>...>();
 }
 
+#if defined(BOOST_DESCRIBE_CXX20)
+
+template<auto V, auto N> struct enum_desc
+{
+    static constexpr auto value() noexcept { return V; }
+    static constexpr auto name() noexcept { return N(); }
+};
+
+#define BOOST_DESCRIBE_ENUM_BEGIN(E) \
+    inline decltype( boost::describe::detail::enum_descriptor_fn_impl( 0
+
+#define BOOST_DESCRIBE_ENUM_ENTRY(E, e) , boost::describe::detail::enum_desc<E::e, []{ return #e; }>{}
+
+#define BOOST_DESCRIBE_ENUM_END(E) ) ) boost_enum_descriptor_fn( E** ) { return {}; }
+
+#else
+
 #define BOOST_DESCRIBE_ENUM_BEGIN(E) \
     inline auto boost_enum_descriptor_fn( E** ) \
     { return boost::describe::detail::enum_descriptor_fn_impl( 0
@@ -53,6 +70,8 @@ template<class... T> auto enum_descriptor_fn_impl( int, T... )
 
 #define BOOST_DESCRIBE_ENUM_END(E) ); }
 
+#endif
+
 } // namespace detail
 
 #if defined(_MSC_VER) && !defined(__clang__)

include/boost/describe/enum_to_string.hpp

@@ -1,7 +1,7 @@
 #ifndef BOOST_DESCRIBE_ENUM_TO_STRING_HPP_INCLUDED
 #define BOOST_DESCRIBE_ENUM_TO_STRING_HPP_INCLUDED
 
-// Copyright 2020, 2021 Peter Dimov
+// Copyright 2020, 2021, 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 
@@ -22,16 +22,34 @@ namespace boost
 namespace describe
 {
 
-template<class E, class De = describe_enumerators<E>>
-char const * enum_to_string( E e, char const* def ) noexcept
+namespace detail
 {
-    char const * r = def;
 
-    mp11::mp_for_each<De>([&](auto D){
+// [&](auto D){ if( e == D.value ) r = D.name; }
+// except constexpr under C++14
 
-        if( e == D.value ) r = D.name;
+template<class E> struct ets_lambda
+{
+    E e;
+    char const** pr;
 
-    });
+    template<class D> constexpr void operator()( D d ) const noexcept
+    {
+        if( e == d.value ) *pr = d.name;
+    }
+};
+
+} // namespace detail
+
+template<class E, class De = describe_enumerators<E>>
+#if !( defined(_MSC_VER) && _MSC_VER == 1900 )
+constexpr
+#endif
+char const* enum_to_string( E e, char const* def ) noexcept
+{
+    char const* r = def;
+
+    mp11::mp_for_each<De>( detail::ets_lambda<E>{ e, &r } );
 
     return r;
 }

include/boost/describe/modifiers.hpp

@@ -25,7 +25,7 @@ enum modifiers
     mod_hidden = 256
 };
 
-BOOST_DESCRIBE_CONSTEXPR_OR_CONST modifiers mod_any_access = static_cast<modifiers>( mod_public | mod_protected | mod_private );
+BOOST_DESCRIBE_INLINE_CONSTEXPR modifiers mod_any_access = static_cast<modifiers>( mod_public | mod_protected | mod_private );
 
 } // namespace describe
 } // namespace boost

test/Jamfile

@@ -7,6 +7,11 @@ import testing ;
 local WERROR = <toolset>msvc:<warnings-as-errors>on <toolset>clang:<warnings-as-errors>on <toolset>gcc:<warnings-as-errors>on ;
 
 project : requirements
+  <library>/boost/describe//boost_describe
+  <library>/boost/container_hash//boost_container_hash
+  <library>/boost/core//boost_core
+  <library>/boost/variant2//boost_variant2
+
   <warnings>extra
   $(WERROR)
   <toolset>clang:<cxxflags>"-Wno-unused-private-field" ;
@@ -80,6 +85,10 @@ run pedantic_members_test.cpp
 
 run enum_from_string_test2.cpp ;
 
+compile nested_enum_test2.cpp ;
+
+compile enum_to_string_test_cx.cpp ;
+
 # examples
 
 obj describe_cxx14 : describe_cxx14.cpp ;
@@ -87,8 +96,8 @@ explicit describe_cxx14 ;
 
 local CXX14 = [ check-target-builds describe_cxx14 describe_cxx14 : : <build>no ] "<toolset>msvc-14.0:<cxxflags>-wd4100" ;
 
-local JSON = <library>/boost//json/<warnings>off "<toolset>msvc-14.2:<cxxflags>-wd5104" ;
-local SERIALIZATION = <library>/boost//serialization/<warnings>off -$(WERROR) ;
+local JSON = <library>/boost/json//boost_json/<warnings>off "<toolset>msvc-14.2:<cxxflags>-wd5104" "<toolset>msvc-14.0:<cxxflags>-wd4996" <undefined-sanitizer>norecover:<link>static ;
+local SERIALIZATION = <library>/boost/serialization//boost_serialization/<warnings>off -$(WERROR) <undefined-sanitizer>norecover:<link>static ;
 
 run ../example/printing_enums_ct.cpp : : : $(CXX14) ;
 run ../example/printing_enums_rt.cpp : : : $(CXX14) ;
@@ -98,9 +107,10 @@ run ../example/print_function.cpp : : : $(CXX14) ;
 run ../example/to_json.cpp : : : $(CXX14) $(JSON) ;
 run ../example/from_json.cpp : : : $(CXX14) $(JSON) ;
 run ../example/serialization.cpp : : : $(CXX14) $(SERIALIZATION) ;
-run ../example/json_rpc.cpp : : : $(CXX14) $(JSON) ;
+run ../example/json_rpc.cpp : : : $(CXX14) $(JSON) <library>/boost/utility//boost_utility
+  "<toolset>gcc-14,<cxxstd>14:<build>no" ; # mysterious segmentation fault
 run ../example/hash_value.cpp : : : $(CXX14) ;
 run ../example/equality.cpp : : : $(CXX14) ;
-link ../example/console.cpp : $(CXX14) $(JSON) ;
+link ../example/console.cpp : $(CXX14) $(JSON) <library>/boost/utility//boost_utility ;
 run ../example/struct_to_tuple.cpp : : : $(CXX14) ;
 run ../example/pm_to_string.cpp : : : $(CXX14) ;

test/bases_test.cpp

@@ -62,6 +62,14 @@ int main() {}
 
 #include <boost/mp11.hpp>
 
+template<typename ...Bases>
+struct ZT: Bases...
+{
+    BOOST_DESCRIBE_CLASS(ZT, (Bases...), (), (), ());
+};
+
+using Z = ZT<X1, X2, X3>;
+
 int main()
 {
     using namespace boost::describe;
@@ -151,6 +159,21 @@ int main()
         BOOST_TEST_EQ( (mp_at_c<L, 1>::modifiers), mod_private | mod_virtual );
     }
 
+    {
+        using L = describe_bases<Z, mod_any_access>;
+
+        BOOST_TEST_EQ( mp_size<L>::value, 3 );
+
+        BOOST_TEST_TRAIT_SAME( typename mp_at_c<L, 0>::type, X1 );
+        BOOST_TEST_EQ( (mp_at_c<L, 0>::modifiers), mod_public );
+
+        BOOST_TEST_TRAIT_SAME( typename mp_at_c<L, 1>::type, X2 );
+        BOOST_TEST_EQ( (mp_at_c<L, 1>::modifiers), mod_public );
+
+        BOOST_TEST_TRAIT_SAME( typename mp_at_c<L, 2>::type, X3 );
+        BOOST_TEST_EQ( (mp_at_c<L, 2>::modifiers), mod_public );
+    }
+
     return boost::report_errors();
 }
 

test/cmake_install_test/CMakeLists.txt

@@ -14,4 +14,4 @@ target_link_libraries(main Boost::describe)
 enable_testing()
 add_test(main main)
 
-add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)
+add_custom_target(check VERBATIM COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)

test/cmake_subdir_test/CMakeLists.txt

@@ -11,7 +11,6 @@ add_subdirectory(../../../assert boostorg/assert)
 add_subdirectory(../../../config boostorg/config)
 add_subdirectory(../../../core boostorg/core)
 add_subdirectory(../../../mp11 boostorg/mp11)
-add_subdirectory(../../../static_assert boostorg/static_assert)
 add_subdirectory(../../../throw_exception boostorg/throw_exception)
 
 add_executable(quick ../quick.cpp)
@@ -20,4 +19,4 @@ target_link_libraries(quick Boost::describe Boost::core)
 enable_testing()
 add_test(quick quick)
 
-add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure --no-tests=error -C $<CONFIG>)
+add_custom_target(check VERBATIM COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure --no-tests=error -C $<CONFIG>)

test/enum_to_string_test_cx.cpp

@@ -0,0 +1,32 @@
+// Copyright 2021, 2025 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/describe/enum_to_string.hpp>
+#include <boost/describe/enum.hpp>
+#include <boost/describe/detail/cx_streq.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(BOOST_DESCRIBE_CXX14)
+
+BOOST_PRAGMA_MESSAGE("Skipping test because C++14 is not available")
+
+#elif defined(_MSC_VER) && _MSC_VER == 1900
+
+BOOST_PRAGMA_MESSAGE("Skipping test because _MSC_VER == 1900")
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+
+BOOST_DEFINE_ENUM_CLASS(E, v1, v2, v3)
+
+using boost::describe::enum_to_string;
+using boost::describe::detail::cx_streq;
+
+STATIC_ASSERT( cx_streq( enum_to_string( E::v1, "" ), "v1" ) );
+STATIC_ASSERT( cx_streq( enum_to_string( E::v2, "" ), "v2" ) );
+STATIC_ASSERT( cx_streq( enum_to_string( E::v3, "" ), "v3" ) );
+STATIC_ASSERT( cx_streq( enum_to_string( (E)17, "def" ), "def" ) );
+
+#endif // !defined(BOOST_DESCRIBE_CXX14)

test/nested_enum_test2.cpp

@@ -0,0 +1,24 @@
+// Copyright 2025 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/describe/enumerators.hpp>
+#include <boost/describe/enum.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(BOOST_DESCRIBE_CXX20)
+
+BOOST_PRAGMA_MESSAGE("Skipping test because BOOST_DESCRIBE_CXX20 isn't defined")
+
+#else
+
+struct X
+{
+    enum E { v1 };
+    BOOST_DESCRIBE_NESTED_ENUM(E, v1)
+
+    using L = boost::describe::describe_enumerators<E>;
+};
+
+#endif

test/pp_for_each_test.cpp

@@ -70,6 +70,19 @@ char const * s49 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i,
 char const * s50 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X);
 char const * s51 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y);
 char const * s52 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z);
+char const * s53 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1);
+char const * s54 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2);
+char const * s55 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3);
+char const * s56 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4);
+char const * s57 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4, 5);
+char const * s58 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4, 5, 6);
+char const * s59 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4, 5, 6, 7);
+char const * s60 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4, 5, 6, 7, 8);
+char const * s61 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4, 5, 6, 7, 8, 9);
+char const * s62 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0);
+char const * s63 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, @);
+char const * s64 = BOOST_DESCRIBE_PP_FOR_EACH(F1, ~, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, @, _);
+
 
 int main()
 {
@@ -126,6 +139,18 @@ int main()
     BOOST_TEST_CSTR_EQ( s50, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWX" );
     BOOST_TEST_CSTR_EQ( s51, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXY" );
     BOOST_TEST_CSTR_EQ( s52, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" );
+    BOOST_TEST_CSTR_EQ( s53, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1" );
+    BOOST_TEST_CSTR_EQ( s54, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12" );
+    BOOST_TEST_CSTR_EQ( s55, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123" );
+    BOOST_TEST_CSTR_EQ( s56, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234" );
+    BOOST_TEST_CSTR_EQ( s57, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345" );
+    BOOST_TEST_CSTR_EQ( s58, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456" );
+    BOOST_TEST_CSTR_EQ( s59, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567" );
+    BOOST_TEST_CSTR_EQ( s60, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678" );
+    BOOST_TEST_CSTR_EQ( s61, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789" );
+    BOOST_TEST_CSTR_EQ( s62, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890" );
+    BOOST_TEST_CSTR_EQ( s63, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890@" );
+    BOOST_TEST_CSTR_EQ( s64, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890@_" );
 
     return boost::report_errors();
 }