clap/examples/tutorial_builder/04_02_validate.rs
Ed Page befee6667b docs: Re-work examples
This creates distinct tutorial examples from complex feature examples
(more how-tos).  Both sets are getting builder / derive versions (at
least the critical ones).
2021-11-30 21:33:52 -06:00

17 lines
490 B
Rust

use clap::{app_from_crate, arg};
fn main() {
let matches = app_from_crate!()
.arg(
arg!(<PORT>)
.help("Network port to use")
.validator(|s| s.parse::<usize>()),
)
.get_matches();
// Note, it's safe to call unwrap() because the arg is required
let port: usize = matches
.value_of_t("PORT")
.expect("'MODE' is required and parsing will fail if its missing");
println!("PORT = {}", port);
}