nlohmann_yaml

A header-only YAML parser that integrates Nlohmann's JSON library, providing a simple way to parse YAML files into familiar JSON objects.

Features

• Header-Only: No compilation required, simply #include <nlohmann/yaml.hpp>
• Efficient Parsing: Optimized for performance with minimal memory overhead
• Easy Integration: Direct conversion to nlohmann::json objects
• Type Detection: Automatic parsing of strings, numbers, booleans, and null values
• Modern C++: Designed for C++17 standard and later
• CMake Support: Proper CMake package configuration
• Comment Handling: Gracefully processes YAML comments
• Stream Support: Parse from strings, files, or any std::istream

Getting Started

Installation

Installation instructions for Linux and Windows are provided below:

Linux

mkdir build
cd build
cmake ..
cmake --build .

Windows

mkdir build
cd build
cmake -DCMAKE_TOOLCHAIN_FILE=c:/vcpkg/scripts/buildsystems/vcpkg.cmake ..
cmake --build .

CMake Integration

target_link_libraries(app PRIVATE nlohmann_yaml::nlohmann_yaml)

Usage

#include <nlohmann/yaml.hpp>

#include <fstream>
#include <iostream>
#include <stdexcept>

nlohmann::json load_yaml(const std::string& path)
{
    std::ifstream ifs(path);
    if (!ifs.is_open()) {
        throw std::runtime_error("Failed to open config file: " + path);
    }

    return nlohmann::parse_yaml(ifs);
}

int main(const int argc, char* argv[]) {
    try {
        nlohmann::json test_json = load_yaml("config.yaml");

        // Print the parsed JSON structure
        std::cout << test_json.dump(2) << std::endl << std::endl;

        return 0;
    } catch (const std::exception& ex) {
        std::cerr << "ERROR: " << ex.what() << std::endl;
        return 1;
    }
}