Parse CLI options in Rust - Basic Recipe

Cargo.toml

[package]
name = "getopt-toy"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
getopts = "0.2"

main.rs

// Most of this is taken directly from https://docs.rs/getopts/latest/getopts/

extern crate getopts;
use getopts::Options;
use std::env;

fn print_usage(program: &str, opts: Options) {
    let brief = format!("Usage: {} FILE [options]", program);
    print!("{}", opts.usage(&brief));
}

fn main() {
    let args: Vec<String> = env::args().collect();
    let program = args[0].clone();
    
    let mut opts = Options::new();
    opts.optopt("o", "", "set output file name", "NAME");
    opts.optflag("h", "help", "print this help menu");
    let matches = match opts.parse(&args[1..]) {
        Ok(m) => { m }
        Err(f) => { panic!("{}", f.to_string()) }
    };
    if matches.opt_present("h") {
        print_usage(&program, opts);
        return;
    }
    let output = matches.opt_str("o");
    let pp = if !matches.free.is_empty() {
        matches.free[0].clone()
    } else {
        print_usage(&program, opts);
        return;
    };
    
}