gistfile1.txt

use clap::{CommandFactory, FromArgMatches, Id};

#[derive(clap::Parser, Debug)]
#[command()]
struct Args {
    #[command(flatten)]
    opts: Opts,
}

#[derive(clap::Args, Debug)]
#[group(multiple = true)]
struct Opts {
    #[arg(short = 'a', action = clap::ArgAction::Append)]
    pub a: Vec<String>,
    #[arg(action = clap::ArgAction::Append)]
    pub b: Vec<String>,
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let matches = Args::command().get_matches();
    // This returns the actual struct with the values
    let args = Args::from_arg_matches(&matches)?;
    // This returns the order of given args between multiple options
    let opt_order: Vec<_> = matches
        .get_many::<Id>("Opts")
        .unwrap().map(|x| x.to_string()).collect();
    println!("{:?}", ordered_opts(args.opts, opt_order));
    Ok(())
}

fn ordered_opts(opts: Opts, id_order: Vec<String>) -> Vec<(String, String)> {
    let mut ordered_opts = vec![];
    let mut a = opts.a.into_iter();
    let mut b = opts.b.into_iter();
    for id in id_order {
        match id.as_str() {
            "a" => ordered_opts.push((id, a.next().unwrap())),
            "b" => ordered_opts.push((id, b.next().unwrap())),
            _ => unreachable!(),
        }
    }
    ordered_opts
}