easy-args

A Rust library for simple and lightweight command-line argument parsing, with:

• Easy to use declarative usage via ArgSpec,
• Zero dependencies with other crates,

It's also worth pointing out what easy-args is not:

• Extensive. Only supports boolean flags, signed and unsigned 64-bit integers and strings and array versions of those types.
• Fast. By no means is it super slow but it hasn't been made with maximum performance in mind.

Documentation:

• API reference (docs.rs)

Usage

Add this to your Cargo.toml:

[dependencies]
easy-args = "0.3.0"

To get started using easy-args.

First you must define an ArgSpec which will determine what the command-line arguments are for your program and will be used by the parser to do some simple checks. You make an ArgSpec with the builder pattern.

let spec = ArgSpec::build()
    .boolean("fullscreen")
    .uinteger_array(2, "size")
    .done()?;

There is an arg_spec! macro which provides a nicer syntax.

let spec = arg_spec! {
  fullscreen: bool,
  size: [u64; 2],
};

Second you call ArgSpecs's parse() method to retrieve the command-line arguments in a processed form.

let args = spec.parse()?;
if args.boolean("fullscreen") == Some(&true) {
    // Put application into fullscreen
}

And that's it! The arguments have been parsed and processed and can be accessed via Args's getter methods. ArgSpecBuilder also has a parse() method so you don't have to make a throwaway variable.

let args = ArgSpec::build()
    .boolean("fullscreen")
    .uinteger_array(2, "size")
    .parse()
    .unwrap();

Versions

easy-args is an immature crate and as such may make breaking changes in future versions.

Current easy-args versions are:

• Version 0.1.0 was released in June 2021, with the very first implementation.
• Version 0.1.1 was released a few hours afterwards to add documentation.
• Version 0.2.0 was released in June 2021, introduced array types, renamed unsigned_integer methods to uinteger and added error checking for to building ArgSpec's.
• Version 0.3.0 was released in June 2021. Reorganised crate into single module to simplify imports. Added features include:
  • arg_spec! macro to provide a nicer syntax for ArgSpec building.
  • f64 and [f64] arguments now supported.

License

easy-args is distributed under the terms of the MIT license.