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noargs

Imperative command-line argument parser library with no dependencies, no macros, and no implicit I/O

4 releases (2 breaking)

Uses new Rust 2024

new 0.2.0 Mar 31, 2025
0.1.1 Mar 29, 2025
0.1.0 Mar 24, 2025
0.0.1 Mar 23, 2025

#189 in Command-line interface

Download history 20/week @ 2025-03-17 530/week @ 2025-03-24

550 downloads per month
Used in rofis

MIT license

70KB
2K SLoC

noargs

noargs Documentation Actions Status License

noargs is an imperative command-line argument parser library for Rust with no dependencies, no macros, and no implicit I/O.

Features

  • Supports the following argument types:
    • Positional arguments (Arg)
    • Named arguments with values (Opt)
    • Named arguments without values (Flag)
    • Subcommands (Cmd)
  • Automatically generates help text
  • Simple and minimal interface due to its imperative nature (no complex DSL)

Examples

The following code demonstrates the basic usage of noargs:

fn main() -> noargs::Result<()> {
    // Create `noargs::RawArgs` having the result of `std::env::args()`.
    let mut args = noargs::raw_args();

    // Set metadata for help.
    args.metadata_mut().app_name = env!("CARGO_PKG_NAME");
    args.metadata_mut().app_description = env!("CARGO_PKG_DESCRIPTION");

    // Handle well-known flags.
    if noargs::VERSION_FLAG.take(&mut args).is_present() {
        println!("{} {}", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"));
        return Ok(());
    }
    if noargs::HELP_FLAG.take(&mut args).is_present() {
        args.metadata_mut().help_mode = true;
    }

    // Handle application specific args.
    let foo: usize = noargs::opt("foo").default("1").take(&mut args).parse()?;
    let bar: bool = noargs::flag("bar").take(&mut args).is_present();
    let baz: Option<String> = noargs::arg("baz").take(&mut args).parse_if_present()?;

    // Check unexpected args and build help text if need.
    if let Some(help) = args.finish()? {
        print!("{help}");
        return Ok(());
    }

    // Do application logic.

    Ok(())

No runtime deps