// Ref https://old.reddit.com/r/programming/comments/1l2h781/on_no_syntactic_support_for_error_handling/mvy5zrd/
use regex::Regex;

fn main() {
    println!("{}", foo("123"));
    println!("{}", bar("123").unwrap_or(0));
    println!("{}", baz("123").unwrap_or(0));
}

fn foo(input: &str) -> isize {
    let p = Regex::new(r"-c(\d{1,3})")
        .expect("We should have written a valid regex. This is a bug in the application.");

    p.captures(input)
        .and_then(|captures| captures.get(1))
        .and_then(|m| m.as_str().parse().ok())
        .unwrap_or(0)
}

fn bar(input: &str) -> Option<isize> {
    let p = Regex::new(r"-c(\d{1,3})").ok()?;

    let captures = p.captures(input)?;
    let matches = captures.get(1)?;
    matches.as_str().parse().ok()
}

fn baz(input: &str) -> Option<isize> {
    Regex::new(r"-c(\d{1,3})")
        .ok()?
        .captures(input)?
        .get(1)?
        .as_str()
        .parse()
        .ok()
}