Optional arguments in Rust

main.rs

type Links = Vec<String>;
type Proxies = Vec<String>;

#[derive(Clone, Debug)]
struct Opts {
    links: Option<Links>,
    proxies: Option<Proxies>,
}

impl Opts {
    fn new() -> Self {
        Opts {
            links: None,
            proxies: None,
        }
    }

    fn with_links(self, input: Vec<&str>) -> Self {
        let mut new = self;
        new.links = Some(input.iter().map(|s| s.to_string()).collect());

        new
    }

    fn with_proxies(self, input: Vec<&str>) -> Self {
        let mut new = self;
        new.proxies = Some(input.iter().map(|s| s.to_string()).collect());

        new
    }
}

fn with_opts(_: &str, args: Opts) {
    println!("{:#?}", args);
}

fn main() {
    with_opts("hello", Opts::new().with_links(vec!["http://blabla.com"]));
    with_opts("hello", Opts::new().with_proxies(vec!["localhost:8080"]));
}