feat: Add CMakeLists.txt files and helper function for building interface libraries. (#17)

Co-authored-by: davidlion <[email protected]>

Author: Bill-hbrhbr

.gersemirc

@@ -1,5 +1,6 @@
 # yamllint disable-line rule:line-length
 # yaml-language-server: $schema=https://raw.githubusercontent.com/BlankSpruce/gersemi/master/gersemi/configuration.schema.json
 
+definitions: ["CMake/ystdlib-cpp-helpers.cmake"]
 line_length: 100
 list_expansion: "favour-expansion"

CMake/ystdlib-cpp-helpers.cmake

@@ -0,0 +1,35 @@
+# Adds a c++20 interface library in the subdirectory NAME with the target NAME and alias
+# NAMESPACE::NAME. Libraries with multiple levels of namespace nesting are currently not supported.
+#
+# @param NAME
+# @param NAMESPACE
+# @param [LIB_BUILD_INTERFACE="${PROJECT_SOURCE_DIR}/src"] The list of include paths for building
+# the library and for external projects that link against it via the add_subdirectory() function.
+function(cpp_library)
+    set(options "")
+    set(oneValueArgs
+        NAME
+        NAMESPACE
+    )
+    set(multiValueArgs LIB_BUILD_INTERFACE)
+    cmake_parse_arguments(arg_cpp_lib "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+
+    # TODO: Turn this into a function for handling other optional params that have default values.
+    if("LIB_BUILD_INTERFACE" IN_LIST arg_cpp_lib_KEYWORDS_MISSING_VALUES)
+        message(
+            FATAL_ERROR
+            "Missing build interface list for ${arg_cpp_lib_NAMESPACE}::${arg_cpp_lib_NAME}."
+        )
+    elseif(NOT DEFINED arg_cpp_lib_LIB_BUILD_INTERFACE)
+        set(arg_cpp_lib_LIB_BUILD_INTERFACE "${PROJECT_SOURCE_DIR}/src")
+    endif()
+
+    add_library(${arg_cpp_lib_NAME} INTERFACE)
+    target_include_directories(
+        ${arg_cpp_lib_NAME}
+        INTERFACE
+            "$<BUILD_INTERFACE:${arg_cpp_lib_LIB_BUILD_INTERFACE}>"
+    )
+    target_compile_features(${arg_cpp_lib_NAME} INTERFACE cxx_std_20)
+    add_library(${arg_cpp_lib_NAMESPACE}::${arg_cpp_lib_NAME} ALIAS ${arg_cpp_lib_NAME})
+endfunction()

CMakeLists.txt

@@ -11,6 +11,14 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS
     FORCE
 )
 
+# Import CMake helper functions
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/CMake)
+include(ystdlib-cpp-helpers)
+
+add_subdirectory(src/ystdlib)
+
+# Test dummy project
 add_executable(dummy)
-target_sources(dummy PRIVATE src/ystdlib/hello.cpp)
+target_sources(dummy PRIVATE src/main.cpp)
+target_link_libraries(dummy PRIVATE ystdlib::testlib)
 target_compile_features(dummy PRIVATE cxx_std_20)

README.md

@@ -2,6 +2,18 @@ ystdlib-cpp
 ===================================
 An open-source C++ library developed and used at YScope.
 
+# Usage
+Clone `ystdlib-cpp` into your project. Then, in your project's `CMakeLists.txt`, add the following:
+```cmake
+add_subdirectory(/path/to/ystdlib-cpp EXCLUDE_FROM_ALL)
+target_link_libraries(<target_name> <link_options>
+    ystdlib::<lib_1> ystdlib::<lib_2> ... ystdlib::<lib_N>
+    # other libs...
+)
+```
+Ensure that `ystdlib-cpp` is either within a subdirectory of the folder containing `CMakeLists.txt`
+or at the same level.
+
 # Contributing
 Follow the steps below to develop and contribute to the project.
 
@@ -15,7 +27,7 @@ Initialize and update submodules:
 git submodule update --init --recursive
 ```
 
-# Building
+## Building
 To build all targets in `ystdlib-cpp`:
 ```shell
 task build:target

src/main.cpp

@@ -0,0 +1,7 @@
+#include <iostream>
+#include <ystdlib/testlib/hello.hpp>
+
+[[nodiscard]] auto main() -> int {
+    std::cout << ystdlib::testlib::hello() << '\n';
+    return 0;
+}

src/ystdlib/CMakeLists.txt

@@ -0,0 +1 @@
+add_subdirectory(testlib)

src/ystdlib/hello.cpp

@@ -0,0 +1 @@
+cpp_library(NAME testlib NAMESPACE ystdlib)

src/ystdlib/testlib/CMakeLists.txt

@@ -0,0 +1,12 @@
+#ifndef YSTDLIB_TESTLIB_HELLO_HPP
+#define YSTDLIB_TESTLIB_HELLO_HPP
+
+#include <string>
+
+namespace ystdlib::testlib {
+[[nodiscard]] inline auto hello() -> std::string {
+    return "Hello, world!";
+}
+}  // namespace ystdlib::testlib
+
+#endif  // YSTDLIB_TESTLIB_HELLO_HPP

src/ystdlib/testlib/hello.hpp

@@ -5,11 +5,15 @@ tasks:
     desc: "Runs the CMake linters."
     sources: &cmake_format_src_files
       - "{{.G_LINT_VENV_CHECKSUM_FILE}}"
+      - "{{.G_YSTDLIB_CPP_SRC_DIR}}/.gersemirc"
       - "{{.ROOT_DIR}}/**/*.cmake"
       - "{{.ROOT_DIR}}/**/*.cmake.in"
       - "{{.ROOT_DIR}}/**/CMakeLists.txt"
+      - "{{.ROOT_DIR}}/.gersemirc"
       - "{{.TASKFILE}}"
       - exclude: "{{.ROOT_DIR}}/**/build/*"
+      - exclude: "{{.ROOT_DIR}}/**/cmake_install.cmake"
+      - exclude: "{{.ROOT_DIR}}/**/CMakeFiles/*"
       - exclude: "{{.ROOT_DIR}}/**/submodules/*"
       - exclude: "{{.ROOT_DIR}}/**/tools/*"
     deps:
@@ -44,7 +48,8 @@ tasks:
       - |-
         . "{{.G_LINT_VENV_DIR}}/bin/activate"
         find . \
-          \( -path '**/build' -o -path '**/submodules' -o -path '**/tools' \) -prune -o \
+          \( -path '**/build' -o -path '**/cmake_install.cmake' -o -path '**/CMakeFiles' \
+          -o -path '**/submodules' -o -path '**/tools' \) -prune -o \
           \( -iname "CMakeLists.txt" -o -iname "*.cmake" -o -iname "*.cmake.in" \) \
           -print0 | \
             xargs -0 gersemi {{.FLAGS}}