C++20 module support

CMakeLists.txt

@@ -2,18 +2,37 @@
 # Distributed under the Boost Software License, Version 1.0.
 # See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
 
-cmake_minimum_required(VERSION 3.5...3.16)
+cmake_minimum_required(VERSION 3.5...3.31)
 
 project(boost_mp11 VERSION 1.88.0 LANGUAGES CXX)
 
-add_library(boost_mp11 INTERFACE)
+if (BOOST_USE_MODULES)
+  add_library(boost_mp11 STATIC)
+  target_sources(boost_mp11 PUBLIC FILE_SET CXX_MODULES BASE_DIRS modules FILES modules/boost_mp11.cppm)
+  set(__scope PUBLIC)
+
+  # Enable and propagate C++23, import std, and the modules macro
+  target_compile_features(boost_mp11 PUBLIC cxx_std_23)
+  set_target_properties(boost_mp11 PROPERTIES CXX_MODULE_STD 1)
+  target_compile_definitions(boost_mp11 PUBLIC BOOST_USE_MODULES)
+
+else()
+  add_library(boost_mp11 INTERFACE)
+  target_compile_features(boost_mp11 INTERFACE cxx_alias_templates cxx_variadic_templates cxx_decltype)
+  set(__scope INTERFACE)
+endif()
+
 add_library(Boost::mp11 ALIAS boost_mp11)
+target_include_directories(boost_mp11 ${__scope} include)
 
-target_include_directories(boost_mp11 INTERFACE include)
-target_compile_features(boost_mp11 INTERFACE cxx_alias_templates cxx_variadic_templates cxx_decltype)
 
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
 
+  # Required to call deprecated FetchContent_Populate
+  if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.30.0")
+    cmake_policy(SET CMP0169 OLD)
+  endif()
+
   # Fetch support files
 
   message(STATUS "Fetching BoostFetch.cmake")

include/boost/mp11/algorithm.hpp

@@ -8,6 +8,13 @@
 //  See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/list.hpp>
 #include <boost/mp11/set.hpp>
 #include <boost/mp11/integral.hpp>
@@ -23,8 +30,8 @@
 #include <boost/mp11/detail/mp_remove_if.hpp>
 #include <boost/mp11/detail/config.hpp>
 #include <boost/mp11/integer_sequence.hpp>
-#include <type_traits>
-#include <utility>
+#include <boost/mp11/detail/std/type_traits.hpp>
+#include <boost/mp11/detail/std/utility.hpp>
 
 #if defined(_MSC_VER) || defined(__GNUC__)
 # pragma push_macro( "I" )
@@ -1350,4 +1357,6 @@ template<class L, class S> using mp_join = mp_apply<mp_append, mp_intersperse<L,
 # pragma pop_macro( "I" )
 #endif
 
+#endif
+
 #endif // #ifndef BOOST_MP11_ALGORITHM_HPP_INCLUDED

include/boost/mp11/bind.hpp

@@ -8,9 +8,16 @@
 //  See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/algorithm.hpp>
 #include <boost/mp11/utility.hpp>
-#include <cstddef>
+#include <boost/mp11/detail/std/cstddef.hpp>
 
 #if defined(_MSC_VER) || defined(__GNUC__)
 # pragma push_macro( "I" )
@@ -117,4 +124,6 @@ template<class Q, class... T> using mp_bind_q = mp_bind<Q::template fn, T...>;
 # pragma pop_macro( "I" )
 #endif
 
+#endif
+
 #endif // #ifndef BOOST_MP11_BIND_HPP_INCLUDED

include/boost/mp11/detail/mp_plus.hpp

@@ -9,7 +9,7 @@
 //  http://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/mp11/detail/config.hpp>
-#include <type_traits>
+#include <boost/mp11/detail/std/type_traits.hpp>
 
 namespace boost
 {

include/boost/mp11/detail/mp_value.hpp

@@ -6,7 +6,7 @@
 // https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/mp11/detail/config.hpp>
-#include <type_traits>
+#include <boost/mp11/detail/std/type_traits.hpp>
 
 #if defined(BOOST_MP11_HAS_TEMPLATE_AUTO)
 

include/boost/mp11/detail/mp_with_index.hpp

@@ -10,8 +10,8 @@
 
 #include <boost/mp11/integral.hpp>
 #include <boost/mp11/detail/config.hpp>
-#include <type_traits>
-#include <utility>
+#include <boost/mp11/detail/std/type_traits.hpp>
+#include <boost/mp11/detail/std/utility.hpp>
 #include <cassert>
 
 #if defined( BOOST_MP11_HAS_CXX14_CONSTEXPR )

include/boost/mp11/detail/std/cstddef.hpp

@@ -0,0 +1,5 @@
+#ifdef BOOST_USE_MODULES
+import std;
+#else
+#include <cstddef>
+#endif

include/boost/mp11/detail/std/tuple.hpp

@@ -0,0 +1,5 @@
+#ifdef BOOST_USE_MODULES
+import std;
+#else
+#include <tuple>
+#endif

include/boost/mp11/detail/std/type_traits.hpp

@@ -0,0 +1,5 @@
+#ifdef BOOST_USE_MODULES
+import std;
+#else
+#include <type_traits>
+#endif

include/boost/mp11/detail/std/utility.hpp

@@ -0,0 +1,5 @@
+#ifdef BOOST_USE_MODULES
+import std;
+#else
+#include <utility>
+#endif

include/boost/mp11/function.hpp

@@ -8,6 +8,13 @@
 // See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/integral.hpp>
 #include <boost/mp11/utility.hpp>
 #include <boost/mp11/detail/mp_list.hpp>
@@ -16,7 +23,7 @@
 #include <boost/mp11/detail/mp_min_element.hpp>
 #include <boost/mp11/detail/mp_void.hpp>
 #include <boost/mp11/detail/config.hpp>
-#include <type_traits>
+#include <boost/mp11/detail/std/type_traits.hpp>
 
 namespace boost
 {
@@ -219,4 +226,6 @@ template<class T1, class... T> using mp_max = mp_max_element<mp_list<T1, T...>,
 } // namespace mp11
 } // namespace boost
 
+#endif
+
 #endif // #ifndef BOOST_MP11_FUNCTION_HPP_INCLUDED

include/boost/mp11/integer_sequence.hpp

@@ -8,8 +8,15 @@
 // See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
 #include <boost/mp11/version.hpp>
-#include <cstddef>
+import boost.mp11;
+
+#else
+
+#include <boost/mp11/version.hpp>
+#include <boost/mp11/detail/std/cstddef.hpp>
 
 #if defined(_MSC_VER) || defined(__GNUC__)
 # pragma push_macro( "I" )
@@ -118,4 +125,6 @@ template<class... T> using index_sequence_for = make_integer_sequence<std::size_
 # pragma pop_macro( "I" )
 #endif
 
+#endif
+
 #endif // #ifndef BOOST_MP11_INTEGER_SEQUENCE_HPP_INCLUDED

include/boost/mp11/integral.hpp

@@ -8,10 +8,17 @@
 //  See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/version.hpp>
 #include <boost/mp11/detail/mp_value.hpp>
-#include <type_traits>
-#include <cstddef>
+#include <boost/mp11/detail/std/type_traits.hpp>
+#include <boost/mp11/detail/std/cstddef.hpp>
 
 #if defined(_MSC_VER) || defined(__GNUC__)
 # pragma push_macro( "I" )
@@ -48,4 +55,6 @@ template<std::size_t N> using mp_size_t = std::integral_constant<std::size_t, N>
 # pragma pop_macro( "I" )
 #endif
 
+#endif
+
 #endif // #ifndef BOOST_MP11_INTEGRAL_HPP_INCLUDED

include/boost/mp11/lambda.hpp

@@ -8,6 +8,13 @@
 //  See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/detail/config.hpp>
 
 #if BOOST_MP11_WORKAROUND(BOOST_MP11_MSVC, <= 1800)
@@ -17,8 +24,8 @@
 #else
 
 #include <boost/mp11/bind.hpp>
-#include <cstddef>
-#include <type_traits>
+#include <boost/mp11/detail/std/cstddef.hpp>
+#include <boost/mp11/detail/std/type_traits.hpp>
 
 #if defined(_MSC_VER) || defined(__GNUC__)
 # pragma push_macro( "I" )
@@ -196,4 +203,6 @@ template<template <class...> class C, class... Ts> struct lambda_impl<C<Ts...>>
 
 #endif // mp_lambda supported
 
+#endif
+
 #endif // #ifndef BOOST_MP11_LAMBDA_HPP_INCLUDED

include/boost/mp11/list.hpp

@@ -8,6 +8,13 @@
 //  See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/integral.hpp>
 #include <boost/mp11/detail/mp_list.hpp>
 #include <boost/mp11/detail/mp_list_v.hpp>
@@ -17,7 +24,7 @@
 #include <boost/mp11/detail/mp_rename.hpp>
 #include <boost/mp11/detail/mp_append.hpp>
 #include <boost/mp11/detail/config.hpp>
-#include <type_traits>
+#include <boost/mp11/detail/std/type_traits.hpp>
 
 #if defined(_MSC_VER) || defined(__GNUC__)
 # pragma push_macro( "I" )
@@ -478,4 +485,6 @@ template<class L, class Q> using mp_transform_third_q = mp_transform_third<L, Q:
 # pragma pop_macro( "I" )
 #endif
 
+#endif
+
 #endif // #ifndef BOOST_MP11_LIST_HPP_INCLUDED

include/boost/mp11/map.hpp

@@ -8,14 +8,21 @@
 //  See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/detail/mp_map_find.hpp>
 #include <boost/mp11/list.hpp>
 #include <boost/mp11/integral.hpp>
 #include <boost/mp11/utility.hpp>
 #include <boost/mp11/algorithm.hpp>
 #include <boost/mp11/function.hpp>
 #include <boost/mp11/set.hpp>
-#include <type_traits>
+#include <boost/mp11/detail/std/type_traits.hpp>
 
 namespace boost
 {
@@ -116,4 +123,6 @@ template<class M> using mp_is_map = typename detail::mp_is_map_impl<M>::type;
 } // namespace mp11
 } // namespace boost
 
+#endif
+
 #endif // #ifndef BOOST_MP11_MAP_HPP_INCLUDED

include/boost/mp11/mpl.hpp

@@ -8,7 +8,16 @@
 // See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/mpl_list.hpp>
 #include <boost/mp11/mpl_tuple.hpp>
 
+#endif
+
 #endif // #ifndef BOOST_MP11_MPL_HPP_INCLUDED

include/boost/mp11/mpl_list.hpp

@@ -8,6 +8,13 @@
 // See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/detail/mpl_common.hpp>
 
 namespace boost
@@ -25,4 +32,6 @@ template<class... T> struct sequence_tag<mp11::mp_list<T...>>
 } // namespace mpl
 } // namespace boost
 
+#endif
+
 #endif // #ifndef BOOST_MP11_MPL_LIST_HPP_INCLUDED

include/boost/mp11/mpl_tuple.hpp

@@ -8,8 +8,15 @@
 // See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt
 
+#if defined(BOOST_USE_MODULES) && !defined(BOOST_MP11_INTERFACE_UNIT)
+
+#include <boost/mp11/version.hpp>
+import boost.mp11;
+
+#else
+
 #include <boost/mp11/detail/mpl_common.hpp>
-#include <tuple>
+#include <boost/mp11/detail/std/tuple.hpp>
 
 namespace boost
 {
@@ -26,4 +33,6 @@ template<class... T> struct sequence_tag<std::tuple<T...>>
 } // namespace mpl
 } // namespace boost
 
+#endif
+
 #endif // #ifndef BOOST_MP11_MPL_TUPLE_HPP_INCLUDED