Large switch env variable to handle library installation selection.

Author: davidlion

.gersemirc

@@ -2,7 +2,7 @@
 # yaml-language-server: $schema=https://raw.githubusercontent.com/BlankSpruce/gersemi/master/gersemi/configuration.schema.json
 
 definitions:
-  - "CMake/ystdlib-helpers.cmake"
+  - "cmake/ystdlib-helpers.cmake"
   - "build/deps/Catch2/Catch2-src/extras/Catch.cmake"
 line_length: 100
 list_expansion: "favour-expansion"

CMake/ystdlib-config.cmake.in

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.23)
 
 project(ystdlib VERSION "0.0.1" LANGUAGES CXX)
 
-list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/CMake")
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake")
 include(ystdlib-helpers)
 include(CMakePackageConfigHelpers)
 include(GNUInstallDirs)
@@ -31,14 +31,27 @@ if("${CMAKE_CXX_COMPILER_VERSION}" VERSION_LESS "${ystdlib_CMAKE_CXX_COMPILER_MI
     )
 endif()
 
-# Enable exporting compile commands
 set(CMAKE_EXPORT_COMPILE_COMMANDS
     ON
     CACHE BOOL
     "Enable/Disable output of compile commands during generation."
     FORCE
 )
 
+set(YSTDLIB_LIBRARIES
+    "containers"
+    "error_handling"
+    "io_interface"
+    "wrapped_facade_headers"
+    CACHE STRING
+    "Semi-colon separated list of libraries to be built."
+)
+
+message(STATUS "Building the following libraries:")
+foreach(lib IN LISTS YSTDLIB_LIBRARIES)
+    message(" - ${lib}")
+endforeach()
+
 if(ystdlib_IS_TOP_LEVEL)
     # Include dependency settings if the project isn't being included as a subproject.
     # NOTE: We mark the file optional because if the user happens to have the dependencies
@@ -53,17 +66,6 @@ if(BUILD_TESTING AND ystdlib_BUILD_TESTING)
     set(ystdlib_ENABLE_TESTS ON)
 endif()
 
-set(boost_find_package_args
-    1.81.0
-    REQUIRED
-    COMPONENTS
-    headers
-)
-find_package(Boost ${boost_find_package_args})
-if(Boost_FOUND)
-    message(STATUS "Found Boost ${Boost_VERSION}.")
-endif()
-
 if(ystdlib_ENABLE_TESTS)
     find_package(Catch2 3.8.0 REQUIRED)
     if(Catch2_FOUND)
@@ -73,7 +75,6 @@ if(ystdlib_ENABLE_TESTS)
     endif()
     include(Catch)
 
-    # Set up the unified unit test target
     set(UNIFIED_UNIT_TEST_TARGET "unit-test-all")
     add_executable(${UNIFIED_UNIT_TEST_TARGET})
     target_link_libraries(${UNIFIED_UNIT_TEST_TARGET} PRIVATE Catch2::Catch2WithMain)
@@ -88,13 +89,12 @@ if(ystdlib_ENABLE_TESTS)
     catch_discover_tests(${UNIFIED_UNIT_TEST_TARGET} WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/testbin)
 endif()
 
-add_subdirectory(src/ystdlib)
-
 set(ystdlib_INSTALL_CONFIG_DIR ${CMAKE_INSTALL_LIBDIR}/cmake/ystdlib)
-install(EXPORT ystdlib-targets NAMESPACE ystdlib:: DESTINATION ${ystdlib_INSTALL_CONFIG_DIR})
+
+add_subdirectory(src/ystdlib)
 
 configure_package_config_file(
-    ${CMAKE_CURRENT_LIST_DIR}/CMake/ystdlib-config.cmake.in
+    ${CMAKE_CURRENT_LIST_DIR}/cmake/ystdlib-config.cmake.in
     ${CMAKE_CURRENT_BINARY_DIR}/ystdlib-config.cmake
     INSTALL_DESTINATION ${ystdlib_INSTALL_CONFIG_DIR}
 )

CMake/ystdlib-helpers.cmake

@@ -45,6 +45,9 @@ task deps:install-all
 ```
 
 ## Building
+
+### Task
+
 To build all targets:
 ```shell
 task build:all
@@ -60,6 +63,27 @@ To build an executable containing a single library's unit tests:
 task build:unit-test-<lib_name>
 ```
 
+### CMake
+
+To build all libraries, run:
+
+```shell
+cmake -S . -D ./build
+cmake --build ./build
+```
+
+To build a subset of libraries set the variable `YSTDLIB_LIBRARIES` to a semi-colon(`;`) separated
+list of library names. The library names match their [directory name in src/](./src/ystdlib).
+For example:
+
+```shell
+cmake -S . -B ./build -DYSTDLIB_LIBRARIES="containers;io_interface"
+cmake --build ./build
+```
+
+It is not necessary to specify libraries your subset depends on. In the example, specifying
+`io_interface` automatically builds `wrapped_facade_headers`.
+
 ## Installing
 
 After [building](#building), install with:

CMakeLists.txt

@@ -0,0 +1,5 @@
+# gersemi: off
+if(NOT TARGET "ystdlib::containers")
+    include("${CMAKE_CURRENT_LIST_DIR}/containers-target.cmake")
+endif()
+# gersemi: on

README.md

@@ -0,0 +1,9 @@
+# gersemi: off
+if(@Boost_FOUND@)
+    find_dependency(Boost @boost_find_package_args@)
+endif()
+
+if(NOT TARGET "ystdlib::error_handling")
+    include("${CMAKE_CURRENT_LIST_DIR}/error_handling-target.cmake")
+endif()
+# gersemi: on

cmake/libs/containers-config.cmake.in

@@ -0,0 +1,9 @@
+# gersemi: off
+if(NOT TARGET "ystdlib::wrapped_facade_headers")
+    include("${CMAKE_CURRENT_LIST_DIR}/wrapped_facade_headers-target.cmake")
+endif()
+
+if(NOT TARGET "ystdlib::io_interface")
+    include("${CMAKE_CURRENT_LIST_DIR}/io_interface-target.cmake")
+endif()
+# gersemi: on

cmake/libs/error_handling-config.cmake.in

@@ -0,0 +1,5 @@
+# gersemi: off
+if(NOT TARGET "ystdlib::wrapped_facade_headers")
+    include("${CMAKE_CURRENT_LIST_DIR}/wrapped_facade_headers-target.cmake")
+endif()
+# gersemi: on

cmake/libs/io_interface-config.cmake.in

@@ -0,0 +1,29 @@
+# gersemi: off
+# this file is preprocessed and should not be linted like a CMake file
+include(CMakeFindDependencyMacro)
+
+@PACKAGE_INIT@
+
+# If no component is specified we require all libraries.
+# We guard against repeatedly including targets to support multiple find_package calls.
+if(NOT ystdlib_FIND_COMPONENTS)
+    set(_YSTDLIB_LIBRARIES "@YSTDLIB_LIBRARIES@")
+    foreach(lib IN LISTS _YSTDLIB_LIBRARIES)
+        if(NOT TARGET "ystdlib::${lib}")
+            include("${CMAKE_CURRENT_LIST_DIR}/libs/${lib}-config.cmake")
+        endif()
+    endforeach()
+else()
+    foreach(lib IN LISTS ystdlib_FIND_COMPONENTS)
+        if(NOT TARGET "ystdlib::${lib}")
+            if(${ystdlib_FIND_REQUIRED_${lib}})
+                include("${CMAKE_CURRENT_LIST_DIR}/libs/${lib}-config.cmake")
+            else()
+                include("${CMAKE_CURRENT_LIST_DIR}/libs/${lib}-config.cmake" OPTIONAL)
+            endif()
+        endif()
+    endforeach()
+endif()
+
+check_required_components(ystdlib)
+# gersemi: on