argz

A light weight C++ in memory argument parser.

Highlights

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

Quick Start

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!

Printing Help

-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

Supported Input Types

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

Accept No Inputs Without Printing Help

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 };