argparse/README.md

Argument Parser

Positional Arguments

argparse::ArgumentParser program("main");

program.add_argument("input");
program.add_argument("output");

program.parse_args({"./main", "rocket.msh", "thrust_profile.csv"});

std::string input = program.get("input");     // "rocket.msh"
std::string output = program.get("output");   // "thrust_profile.csv"

Optional Arguments

argparse::ArgumentParser program("main");

program.add_argument("--config")
  .help("configuration file")
  .default_value(std::string("config.json"));

program.add_argument("-n", "--num_iterations")
  .help("The list of input files")
  .action([](const std::string& value) { return std::stoi(value); });

program.parse_args({"./main", "-n", "36"});

std::string config = program.get("--config");   // config.json
int num_iterations = program.get<int>("-n");    // 36

Vector of Arguments

argparse::ArgumentParser program("main");

program.add_argument("--input_files")
  .help("The list of input files")
  .nargs(3);

program.parse_args({"./main", "--input_files", "config.yml", "System.xml"});

auto files = program.get<std::vector<std::string>>("--input_files");  // {"config.yml", "System.xml"}

Compound Toggle Arguments

argparse::ArgumentParser program("test");

program.add_argument("-a")
  .default_value(false)
  .implicit_value(true);

program.add_argument("-b")
  .default_value(false)
  .implicit_value(true);

program.add_argument("-c")
  .nargs(2)
  .action([](const std::string& value) { return std::stof(value); });

program.parse_args({ "./main", "-abc", "3.14", "2.718" });

auto a = program.get<bool>("-a");                // true
auto b = program.get<bool>("-b");                // true
auto c = program.get<std::vector<float>>("-c");  // {3.14f, 2.718f}