use clap; // 2.33.0
use clap::{App, Arg, ArgMatches};

pub struct CLI {
    clap: App<'static,'static>,
}

impl CLI {

    pub fn new() -> CLI {

        CLI{
            // you could do it here
            clap: App::new("My Super Program").arg(
                Arg::with_name("config")
                .short("c")
                .long("config")
                .value_name("FILE")
                .help("Sets a custom config file")
                .takes_value(true)
            ),
        }

    }

    pub fn setup(&mut self, line: String) -> () {
        // or here
        self.clap = App::new("My Super Program").arg(
            Arg::with_name("config")
            .short("c")
            .long("config")
            .value_name("FILE")
            .help("Sets a custom config file")
            .takes_value(true)
        );
    }
}