Function help

src/exec/CommandParser.cpp:14–84

#include "color.hpp"

static void help(std::filesystem::path program, std::string desc,
    std::vector<std::variant<CommandParser::Fixed, CommandParser::Optional>> options
){
    std::cerr << desc << std::endl;
    // Usage
    std::cerr << std::endl << "Usage: " << program.filename().string() << " [-h | --help]";
    bool showed_dashdash = false;
    for(std::variant<CommandParser::Fixed, CommandParser::Optional> option : options){
        std::visit(overloaded {
            [&](CommandParser::Fixed& opt){
                if(!showed_dashdash){
                    std::cerr << " [--]";
                    showed_dashdash = true;
                }
                std::cerr << " " << opt.name;
                switch(opt.number){
                    case (unsigned)-1:
                        std::cerr << "...";
                    break;
                    case 0:
                    case 1:
                    break;
                    default:
                        std::cerr << "{" << opt.number << "}";
                    break;
                }
            },
            [&](CommandParser::Optional& opt){
                std::cerr << " [";
                if(!opt.alias.empty()){
                    std::cerr << opt.alias << " | ";
                }
                std::cerr << opt.name << "]";
                switch(opt.number){
                    case (unsigned)-1:
                        std::cerr << "...";
                    break;
                    case 0:
                    break;
                    case 1:
                        std::cerr << "?";
                    break;
                    default:
                        std::cerr << "{" << opt.number << "}";
                    break;
                }
            }
        }, option);
    }

    // Options
    std::cerr << std::endl << std::endl << "Options:" << std::endl;
    std::cerr << "  --help, -h\t\tShow help message" << std::endl;
    std::cerr << "  --\t\t\tEnd of options; remaining arguments are positional" << std::endl;
    for(auto& option : options){
        std::visit(overloaded {
            [&](CommandParser::Fixed& opt){
                std::cerr << "  " << opt.name << "\t\t" << opt.desc << std::endl;