libconfig

libconfig

libconfig is the unified configuration module for SERiF and related projects

This has been broken out of the main serif project to allow for more modularity

Building

In order to build libconfig you need meson>=1.5.0. This can be installed with pip

pip install "meson>=1.5.0"

Then from the root libconfig directory it is as simple as

meson setup build --buildtype=release
meson compile -C build
meson test -C build

this will auto generate a pkg-config file for you so that linking other libraries to libconfig is easy.

Usage

libconfig makes use of reflect-cpp to provide compile time reflection and serialization/deserialization of configuration structs. This allows for config options to be defined in code and strongly typed.

Basic Usage

#include "fourdst/config/config.h"
#include <string>
#include <print>
 
struct MyPhysicsOptions {
    int gravity = 10;
    float friction = 0.5f;
    bool enable_wind = false;
};
 
struct MyControlOptions {
    double time_step = 0.01;
    double max_time = 100.0;
};
 
struct MySimulationConfig {
    std::string name = "my_simulation";
    MyPhysicsOptions physics;
    MyControlOptions control;
};
 
int main() {
    fourdst::config::Config<MySimulationConfig> cfg;
    
    // You can save the default config to a file
    cfg.save("default_config.toml");
    
    // You can save the json schema for the config
    // This allows editors like VS Code to provide autocompletion
    fourdst::config::Config<MySimulationConfig>::save_schema("config.schema.json");
    
    // You can load a config from a file
    try {
        cfg.load("my_config.toml");
    } catch (const fourdst::config::exceptions::ConfigError& e) {
        std::println("Error loading config: {}", e.what());
    }
    
    // You can access the config values
    std::println("My Simulation Name: {}, My Simulation Gravity: {}", cfg->name, cfg->physics.gravity);
}

CLI Integration

libconfig integrates with CLI11 to automatically expose configuration fields as command-line arguments.

#include "CLI/CLI.hpp"
#include "fourdst/config/config.h"
 
int main(int argc, char** argv) {
    fourdst::config::Config<MySimulationConfig> cfg;
    CLI::App app("My Application");
 
    // Automatically registers:
    // --name
    // --physics.gravity
    // --physics.friction
    // --physics.enable_wind
    // ... and so on
    fourdst::config::register_as_cli(cfg, app);
 
    CLI11_PARSE(app, argc, argv);
    
    // cfg is now populated with values from CLI arguments
    return 0;
}

Example output TOML

[main]
name = "my_simulation"
[main.physics]
gravity = 10
friction = 0.5
enable_wind = false
[main.control]
time_step = 0.01
max_time = 100.0