Module clap::_derive::_cookbook::escaped_positional

Available on crate feature unstable-doc only.

Example (Builder API)

use clap::{arg, command, value_parser, ArgAction};

fn main() {
    let matches = command!() // requires `cargo` feature
        .arg(arg!(eff: -f).action(ArgAction::SetTrue))
        .arg(
            arg!(pea: -p <PEAR>)
                .required(false)
                .value_parser(value_parser!(String)),
        )
        .arg(
            // Indicates that `slop` is only accessible after `--`.
            arg!(slop: [SLOP])
                .multiple_values(true)
                .last(true)
                .value_parser(value_parser!(String)),
        )
        .get_matches();

    // This is what will happen with `myprog -f -p=bob -- sloppy slop slop`...

    // -f used: true
    println!("-f used: {:?}", matches.get_flag("eff"));
    // -p's value: Some("bob")
    println!("-p's value: {:?}", matches.get_one::<String>("pea"));
    // 'slops' values: Some(["sloppy", "slop", "slop"])
    println!(
        "'slops' values: {:?}",
        matches
            .get_many::<String>("slop")
            .map(|vals| vals.collect::<Vec<_>>())
            .unwrap_or_default()
    );

    // Continued program logic goes here...
}

This requires enabling the cargo feature flag.

You can use -- to escape further arguments.

Let’s see what this looks like in the help:

$ escaped-positional --help
clap [..]
A simple to use, efficient, and full-featured Command Line Argument Parser

USAGE:
    escaped-positional[EXE] [OPTIONS] [-- <SLOP>...]

ARGS:
    <SLOP>...    

OPTIONS:
    -f               
    -h, --help       Print help information
    -p <PEAR>        
    -V, --version    Print version information

Here is a baseline without any arguments:

$ escaped-positional
-f used: false
-p's value: None
'slops' values: []

Notice that we can’t pass positional arguments before --:

$ escaped-positional foo bar
? failed
error: Found argument 'foo' which wasn't expected, or isn't valid in this context

USAGE:
    escaped-positional[EXE] [OPTIONS] [-- <SLOP>...]

For more information try --help

But you can after:

$ escaped-positional -f -p=bob -- sloppy slop slop
-f used: true
-p's value: Some("bob")
'slops' values: ["sloppy", "slop", "slop"]

As mentioned, the parser will directly pass everything through:

$ escaped-positional -- -f -p=bob sloppy slop slop
-f used: false
-p's value: None
'slops' values: ["-f", "-p=bob", "sloppy", "slop", "slop"]