project-euler-solutions/.opencode/cmake-plan.md

CMake 2026 Project Setup Plan

Overview

This document outlines the technical plan for setting up a CMake-based C++ project with the following requirements:

• clang++ compiler with C++23 defaults
• Automatic source file discovery in src/ directory
• Executable generation from files containing 'main' in filename
• External dependency handling for git submodules
• Organized compile flags and variables

Key Components

1. Compiler Configuration

• Use clang++ as the C++ compiler
• Set C++ standard to C++23
• Configure appropriate compiler flags for clang

2. Source File Discovery

• Scan src/ directory for all .cpp files
• Use regex pattern .*main.*\.cpp$ to identify main files
• Separate main files from other source files

3. Executable Generation

• Automatically create executables from files with 'main' in filename
• Create a library from all non-main source files
• Link the library to each executable

4. External Dependency Management

• Handle dependencies in external/ directory
• Example: spdlog in external/spdlog with namespace spdlog
• Create interface libraries for external dependencies

5. Compile Flags Organization

• Debug build flags: -g -O0 -Wall -Wextra
• Release build flags: -O3 -DNDEBUG -Wall -Wextra
• Common flags: -std=c++23 -fPIC

Implementation Details

Regex Pattern

.*main.*\.cpp$

Used to detect files containing 'main' in their filename.

Directory Structure

• src/ - Source files directory
• external/ - Git submodules directory
• include/ - Header files directory

File Processing Logic

1. Find all .cpp files in src/
2. Separate main files from other source files
3. Create library from non-main files
4. Generate executables from main files
5. Link library and external dependencies to each executable

CMake Commands Used

• cmake_minimum_required(VERSION 3.15)
• project(ProjectEuler CXX)
• file(GLOB_RECURSE)
• list(APPEND)
• add_executable()
• add_library()
• target_link_libraries()
• target_compile_features()
• find_package()
• add_subdirectory()