A light weight C++ in memory argument parser.

• Single header file
• Requires C++20
• Less than 200 lines of code
• Apache 2.0 License

Simply include argz.hpp and you're good to go.

#include <argz/argz.hpp>

Start with an about: argz::about

constexpr std::string_view version = "1.2.3";
argz::about about{ "My program description", version };

To add a new argument, simply create argz::options. Provide a list of argument names that you want to group together, e.g. -i and --input.

std::string input{};
std::string study{};
int number = 123;
bool boolean = true;
std::optional<int> number_opt{};
argz::options opts{
   { { "input", 'i' }, input, "the input file"},
   { { "study", 's' }, study, "a study file"},
   { { "number" }, number, "input an int"},
   { { "boolean" }, boolean, "a boolean" },
   { { "number_opt" }, number_opt, "input an int"}
};

Now to parse command line arguments:

try {
    argz::parse(about, opts, argc, argv);
}
catch (const std::exception& e) {
    std::cerr << e.what() << '\n';
}

That is all!

Note that we don't have to cast out (.e.g. .as<int>) from our argument parser because it reads directly into the variables passed in as options!

-h prints a help message, including the program usage and information about the arguments registered with the Argz Parser. An example help message:

My program description
Version: 1.2.3

-h, --help              write help to console
-v, --version           write the version to console
-i, --input             the input file
-s, --study             a study file
--number                input an int, default: 123
--boolean               a boolean, default: 1

bool, int32_t, uint32_t, int64_t, uint64_t, std::string

And std::optional<T> where T is any of the above types except bool

By default the help is printed when no inputs are given. If this behavior is not desirable, set print_help_when_no_options to false inside of argz::about.

argz::about about{ "My program description", version,
                 .print_help_when_no_options = false };