Module clap::_cookbook::escaped_positional
source · [−]Available on crate feature
unstable-doc
only.Expand description
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_one::<bool>("eff").expect("defaulted by clap")
);
// -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"]