Module clap::_derive::_cookbook::escaped_positional_derive
source · Available on crate feature
unstable-doc
only.Expand description
Example (Derive API)
use clap::Parser;
#[derive(Parser)] // requires `derive` feature
#[command(author, version, about, long_about = None)]
struct Cli {
#[arg(short = 'f')]
eff: bool,
#[arg(short = 'p', value_name = "PEAR")]
pea: Option<String>,
#[arg(last = true)]
slop: Vec<String>,
}
fn main() {
let args = Cli::parse();
// This is what will happen with `myprog -f -p=bob -- sloppy slop slop`...
println!("-f used: {:?}", args.eff); // -f used: true
println!("-p's value: {:?}", args.pea); // -p's value: Some("bob")
println!("'slops' values: {:?}", args.slop); // 'slops' values: Some(["sloppy", "slop", "slop"])
// Continued program logic goes here...
}
This requires enabling the derive
feature flag.
You can use --
to escape further arguments.
Let’s see what this looks like in the help:
$ escaped-positional-derive --help
A simple to use, efficient, and full-featured Command Line Argument Parser
Usage: escaped-positional-derive[EXE] [OPTIONS] [-- <SLOP>...]
Arguments:
[SLOP]...
Options:
-f
-p <PEAR>
-h, --help Print help information
-V, --version Print version information
Here is a baseline without any arguments:
$ escaped-positional-derive
-f used: false
-p's value: None
'slops' values: []
Notice that we can’t pass positional arguments before --
:
$ escaped-positional-derive foo bar
? failed
error: Found argument 'foo' which wasn't expected, or isn't valid in this context
Usage: escaped-positional-derive[EXE] [OPTIONS] [-- <SLOP>...]
For more information try '--help'
But you can after:
$ escaped-positional-derive -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-derive -- -f -p=bob sloppy slop slop
-f used: false
-p's value: None
'slops' values: ["-f", "-p=bob", "sloppy", "slop", "slop"]