clap_app.rs

use clap::{App, AppSettings, Arg};

fn main() {
    let matches = App::new("myprog")
        .setting(AppSettings::SubcommandsNegateReqs)
        .subcommand(
            App::new("config").about("configuration mgmt").arg(
                Arg::new("reset")
                    .short('r')
                    .about("reset config to defaults"),
            ),
        )
        .arg(
            Arg::new("slop").index(1).multiple(true).required(true), //.last(true)
        )
        .get_matches();

    if let Some(matches) = matches.subcommand_matches("config") {
        if matches.is_present("reset") {
            println!("config --reset TRUE");
        }
    }
    println!(
        "'slops' values: {:?}",
        matches
            .values_of("slop")
            .map(|vals| vals.collect::<Vec<_>>())
    );
}