clap/examples/11_only_specific_values.rs
Ed Page bfa02fd418 test: More thoroughly test examples
This ports our example testing over to [trycmd](https://docs.rs/) so
we can:
- More thoroughly test our examples
- Provide always-up-to-date example usage

The old way of testing automatically picked up examples.  This new way
requires we have a `.md` file that uses the example in some way.

Notes:
- Moved overall example description to the `.md` file
- I added cross-linking between related examples
- `14_groups` had a redundant paragraph (twice talked about "one and
  only one"
2021-11-23 13:13:41 -06:00

28 lines
708 B
Rust

use clap::{App, Arg};
fn main() {
let matches = App::new("myapp")
.about("does awesome things")
.arg(
Arg::new("MODE")
.help("What mode to run the program in")
.index(1)
.possible_values(["fast", "slow"])
.required(true),
)
.get_matches();
// Note, it's safe to call unwrap() because the arg is required
match matches
.value_of("MODE")
.expect("'MODE' is required and parsing will fail if its missing")
{
"fast" => {
println!("Hare");
}
"slow" => {
println!("Tortoise");
}
_ => unreachable!(),
}
}