CMakeLists.txt

# CMake 3.30 is required for C++23 `import std` support;
cmake_minimum_required(VERSION 3.30...4.2)

include(cmake/prelude.cmake)

#==================================================
project(my_package VERSION 0.2.0 LANGUAGES CXX)
#==================================================

set(CMAKE_CXX_VISIBILITY_PRESET hidden)
set(CMAKE_VISIBILITY_INLINES_HIDDEN YES)

set(CMAKE_SKIP_TEST_ALL_DEPENDENCY NO)

if(PROJECT_IS_TOP_LEVEL)
    include(cmake/AddUninstallTarget.cmake)
endif()

include(cmake/cxx-modules-rules.cmake)

##################################################
add_library(Algo)
add_library(my_package::Algo ALIAS Algo)
target_sources(
    Algo
    PRIVATE algo-impl.cpp
    PUBLIC FILE_SET CXX_MODULES FILES algo-interface.cppm
)

# CMake requires the language standard to be specified as compile feature
# when a target provides C++23 modules and the target will be installed
target_compile_features(Algo PUBLIC cxx_std_23)

if(CMAKE_CXX_MODULE_STD)
    target_compile_definitions(Algo PUBLIC HAS_IMPORT_STD)
else()
    message(FATAL_ERROR "Missing support for CMAKE_CXX_MODULE_STD!")
endif()

# XXX target_link_libraries(Algo PUBLIC $<BUILD_INTERFACE:a4z::commonCompilerWarnings>)

include(GenerateExportHeader)
generate_export_header(Algo CUSTOM_CONTENT_FROM_VARIABLE)
target_sources(
    Algo
    PUBLIC
        FILE_SET HEADERS
            BASE_DIRS ${CMAKE_CURRENT_BINARY_DIR}
            FILES ${CMAKE_CURRENT_BINARY_DIR}/algo_export.h
)

if(NOT CMAKE_SKIP_INSTALL_RULES)
    include(CPack)
    include(GNUInstallDirs)
    include(CMakePackageConfigHelpers)

    write_basic_package_version_file(
        "my_package-config-version.cmake"
        COMPATIBILITY SameMajorVersion
    )

    install(
        TARGETS Algo
        EXPORT my_package-targets
        # ... a few details omitted, see the "Deep CMake For Library Authors" talk
        FILE_SET CXX_MODULES
        # There's currently no convention for this location, see discussion below
        DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/my_package/modules
        CXX_MODULES_BMI
            DESTINATION
                ${CMAKE_INSTALL_LIBDIR}/cmake/my_package/bmi-${CMAKE_CXX_COMPILER_ID}_$<CONFIG>
        FILE_SET HEADERS
            DESTINATION
                ${CMAKE_INSTALL_INCLUDEDIR} # Same as default, could be omitted
        INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
    )
    install(
        EXPORT my_package-targets
        DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/my_package
        CXX_MODULES_DIRECTORY
        .
        NAMESPACE my_package::
    )
    install(
        FILES "${PROJECT_BINARY_DIR}/my_package-config-version.cmake"
        DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/my_package
    )
    # The following file includes the my_package-targets.cmake file
    install(
        FILES cmake/my_package-config.cmake
        DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/my_package
    )
endif()

if(PROJECT_IS_TOP_LEVEL)
    enable_testing()
    add_subdirectory(example)
endif()

if(ALGO_USE_MODULES)
    ##################################################
    return()
    ##################################################
endif()

# project(
#   cmake-init-modules
#   VERSION 0.2.0
#   DESCRIPTION "Short description"
#   HOMEPAGE_URL "https://example.com/"
#   LANGUAGES CXX)

include(cmake/variables.cmake)

# ---- Declare library ----

add_library(cmake-init-modules_cmake-init-modules source/cmake-init-modules.cpp)
add_library(
    cmake-init-modules::cmake-init-modules
    ALIAS cmake-init-modules_cmake-init-modules
)

include(GenerateExportHeader)
generate_export_header(
    cmake-init-modules_cmake-init-modules
    BASE_NAME cmake-init-modules
    EXPORT_FILE_NAME export/cmake-init-modules/cmake-init-modules_export.hpp
    CUSTOM_CONTENT_FROM_VARIABLE pragma_suppress_c4251
)

target_sources(
    cmake-init-modules_cmake-init-modules
    PUBLIC
        FILE_SET HEADERS
            BASE_DIRS ${PROJECT_BINARY_DIR}/export ${PROJECT_SOURCE_DIR}/include
            FILES
                include/cmake-init-modules/cmake-init-modules.hpp
                ${PROJECT_BINARY_DIR}/export/cmake-init-modules/cmake-init-modules_export.hpp
)

if(NOT BUILD_SHARED_LIBS)
    target_compile_definitions(
        cmake-init-modules_cmake-init-modules
        PUBLIC CMAKE_INIT_MODULES_STATIC_DEFINE
    )
endif()

set_target_properties(
    cmake-init-modules_cmake-init-modules
    PROPERTIES
        CXX_VISIBILITY_PRESET hidden
        VISIBILITY_INLINES_HIDDEN YES
        VERSION "${PROJECT_VERSION}"
        SOVERSION "${PROJECT_VERSION_MAJOR}"
        EXPORT_NAME cmake-init-modules
        OUTPUT_NAME cmake-init-modules
)

target_compile_features(cmake-init-modules_cmake-init-modules PUBLIC cxx_std_23)

# ---- Install rules ----

if(NOT CMAKE_SKIP_INSTALL_RULES)
    include(cmake/install-rules.cmake)
endif()

# ---- Examples ----
enable_testing()

# if(PROJECT_IS_TOP_LEVEL)
#   option(BUILD_EXAMPLES "Build examples tree." "${cmake-init-modules_DEVELOPER_MODE}")
#   if(BUILD_EXAMPLES)
#     add_subdirectory(example)
#   endif()
# endif()

# ---- Developer mode ----

if(NOT cmake-init-modules_DEVELOPER_MODE)
    return()
elseif(NOT PROJECT_IS_TOP_LEVEL)
    message(
        AUTHOR_WARNING
        "Developer mode is intended for developers of cmake-init-modules"
    )
endif()

include(cmake/dev-mode.cmake)
##################################################