clap/examples/11_OnlySpecificValues.rs
Kevin K 0cc2f69839 feat(arg): allow other types besides Vec for multiple value settings
Breaking Change

Instead of requiring a Vec<&str> for various Arg::*_all() and
Arg::possible_values() methods this
commit now requires a generic IntoIterator<Item=AsRef<str>> which allows
things such as constant arrays. This change requires that any
Arg::*_all() methods be changed from vec!["val", "val"] -> let vals =
["val", "val"]; some_arg.possible_values(&vals) (or vals.iter()).

Closes #87
2015-04-29 17:52:13 -04:00

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1.3 KiB
Rust

extern crate clap;
use clap::{App, Arg};
fn main() {
// If you have arguments of specific values you want to test for, you can use the
// .possible_values() method of Arg
//
// This allows you specify the valid values for that argument. If the user does not use one of
// those specific values, they will receive a graceful exit with error message informing them
// of the mistake, and what the possible valid values are
//
// For this example, assume you want one positional argument of either "fast" or "slow"
// i.e. the only possible ways to run the program are "myprog fast" or "myprog slow"
let mode_vals = ["fast", "slow"];
let matches = App::new("myapp").about("does awesome things")
.arg(Arg::with_name("MODE")
.help("What mode to run the program in")
.index(1)
.possible_values(&mode_vals)
.required(true))
.get_matches();
// Note, it's safe to call unwrap() because the arg is required
match matches.value_of("MODE").unwrap() {
"fast" => {
// Do fast things...
},
"slow" => {
// Do slow things...
},
_ => unreachable!()
}
}