clap/examples/tutorial_builder/04_01_enum.rs
Ed Page 9e38353442 fix(derive): Clarify ArgEnum as ValueEnum
We aren't enumerating arguments but values for an argument, so the name
should reflect that.

This will be important as part of #1807 when we have more specific
attribute names.
2022-06-08 11:14:09 -05:00

32 lines
761 B
Rust

// Note: this requires the `cargo` feature
use clap::{arg, command, value_parser, ValueEnum};
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ValueEnum)]
enum Mode {
Fast,
Slow,
}
fn main() {
let matches = command!()
.arg(
arg!(<MODE>)
.help("What mode to run the program in")
.value_parser(value_parser!(Mode)),
)
.get_matches();
// Note, it's safe to call unwrap() because the arg is required
match matches
.get_one::<Mode>("MODE")
.expect("'MODE' is required and parsing will fail if its missing")
{
Mode::Fast => {
println!("Hare");
}
Mode::Slow => {
println!("Tortoise");
}
}
}