feat: update build system to v4

CMakeLists.txt

@@ -1,87 +1,55 @@
-cmake_minimum_required(VERSION 3.5)
-enable_testing()
+cmake_minimum_required(VERSION 3.22)
+project(toml11 LANGUAGES CXX VERSION 4.0.0)
 
-project(toml11 VERSION 3.8.1)
+include(CMakeDependentOption)
+include(CTest)
 
-option(toml11_BUILD_TEST "Build toml tests" OFF)
-option(toml11_INSTALL "Install CMake targets during install step." ON)
-option(toml11_TEST_WITH_ASAN  "use LLVM address sanitizer" OFF)
-option(toml11_TEST_WITH_UBSAN "use LLVM undefined behavior sanitizer" OFF)
+option(TOML11_PRECOMPILE "precompile toml11 library" OFF)
 
-option(TOML11_USE_UNRELEASED_TOML_FEATURES
-    "use features in toml-lang/toml master while testing" OFF)
+cmake_dependent_option(TOML11_INSTALL "install toml11 library" ON
+    "${CMAKE_PROJECT_NAME} STREQUAL ${PROJECT_NAME}" OFF)
+cmake_dependent_option(TOML11_BUILD_EXAMPLES "build toml11 examples" OFF
+    "${CMAKE_PROJECT_NAME} STREQUAL ${PROJECT_NAME}" OFF)
+cmake_dependent_option(TOML11_BUILD_TESTS "build toml11 unit tests" OFF
+    "${CMAKE_PROJECT_NAME} STREQUAL ${PROJECT_NAME}; ${BUILD_TESTING}" OFF)
+cmake_dependent_option(TOML11_BUILD_TOML_TESTS "build toml11 toml-test encoder & decoder" OFF
+    "${CMAKE_PROJECT_NAME} STREQUAL ${PROJECT_NAME}" OFF)
+cmake_dependent_option(TOML11_TEST_WITH_ASAN  "build toml11 unit tests with asan" OFF
+    "${TOML11_BUILD_TESTS}" OFF)
+cmake_dependent_option(TOML11_TEST_WITH_UBSAN "build toml11 unit tests with ubsan" OFF
+    "${TOML11_BUILD_TESTS}" OFF)
 
-if(MSVC)
-#     add_definitions("/Zc:__cplusplus")  # define __cplusplus value correctly
-    add_definitions("/utf-8")           # enable to use u8"" literal
-    if(MSVC_VERSION LESS 1910)
-        message(STATUS "MSVC < 1910. DEFINE_CONVERSION_NON_INTRUSIVE is disabled")
-        add_definitions(-DTOML11_WITHOUT_DEFINE_NON_INTRUSIVE)
-    elseif(MSVC_VERSION LESS 1920)
-        add_definitions("/experimental:preprocessor") # MSVC 2017
-    else()
-        add_definitions("/Zc:preprocessor") # MSVC 2019
+if(${TOML11_TEST_WITH_ASAN} AND ${TOML11_TEST_WITH_UBSAN})
+    message(FATAL_ERROR "trying to build tests with BOTH asan and ubsan")
+endif()
+
+include(GNUInstallDirs)
+
+set(TOML11_INSTALL_CMAKE_DIR   ${CMAKE_INSTALL_LIBDIR}/cmake/toml11)
+set(TOML11_INSTALL_INCLUDE_DIR ${CMAKE_INSTALL_INCLUDEDIR})
+set(TOML11_CONFIG_DIR          ${CMAKE_CURRENT_BINARY_DIR}/cmake)
+set(TOML11_CONFIG              ${TOML11_CONFIG_DIR}/toml11Config.cmake)
+set(TOML11_CONFIG_VERSION      ${TOML11_CONFIG_DIR}/toml11ConfigVersion.cmake)
+
+# root project?
+if(${CMAKE_PROJECT_NAME} STREQUAL ${PROJECT_NAME})
+    if(NOT DEFINED CMAKE_CXX_STANDARD)
+        set(CMAKE_CXX_STANDARD 11)
+    endif()
+    if(NOT DEFINED CMAKE_CXX_EXTENSIONS)
+        set(CMAKE_CXX_EXTENSIONS OFF)
+    endif()
+    if(NOT DEFINED CMAKE_CXX_STANDARD_REQUIRED)
+        set(CMAKE_CXX_STANDARD_REQUIRED ON)
+    endif()
+
+    if(${TOML11_BUILD_TESTS})
+        add_subdirectory(tests)
+    endif()
+
+    if(${TOML11_BUILD_EXAMPLES})
+        add_subdirectory(examples)
     endif()
 endif()
 
-# Set some common directories
-include(GNUInstallDirs)
-set(toml11_install_cmake_dir         ${CMAKE_INSTALL_LIBDIR}/cmake/toml11)
-set(toml11_install_include_dir       ${CMAKE_INSTALL_INCLUDEDIR})
-set(toml11_config_dir                ${CMAKE_CURRENT_BINARY_DIR}/cmake/)
-set(toml11_config                    ${toml11_config_dir}/toml11Config.cmake)
-set(toml11_config_version            ${toml11_config_dir}/toml11ConfigVersion.cmake)
-
-add_library(toml11 INTERFACE)
-target_include_directories(toml11 INTERFACE
-    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
-    $<INSTALL_INTERFACE:${toml11_install_include_dir}>
-)
-add_library(toml11::toml11 ALIAS toml11)
-
-# Write config and version config files
-include(CMakePackageConfigHelpers)
-write_basic_package_version_file(
-    ${toml11_config_version}
-    VERSION ${toml11_VERSION}
-    COMPATIBILITY SameMajorVersion
-)
-
-if (toml11_INSTALL)
-    configure_package_config_file(
-        cmake/toml11Config.cmake.in
-        ${toml11_config}
-        INSTALL_DESTINATION ${toml11_install_cmake_dir}
-        PATH_VARS toml11_install_cmake_dir
-    )
-
-    # Install config files
-    install(FILES ${toml11_config} ${toml11_config_version}
-        DESTINATION ${toml11_install_cmake_dir}
-    )
-
-    # Install header files
-    install(
-        FILES toml.hpp
-        DESTINATION "${toml11_install_include_dir}"
-    )
-    install(
-        DIRECTORY "toml"
-        DESTINATION "${toml11_install_include_dir}"
-        FILES_MATCHING PATTERN "*.hpp"
-    )
-
-    # Export targets and install them
-    install(TARGETS toml11
-        EXPORT toml11Targets
-    )
-    install(EXPORT toml11Targets
-        FILE toml11Targets.cmake
-        DESTINATION ${toml11_install_cmake_dir}
-        NAMESPACE toml11::
-    )
-endif()
-
-if (toml11_BUILD_TEST)
-    add_subdirectory(tests)
-endif ()
+add_subdirectory(src)