InputRange.rs

/// String parsing example
impl FromStr for InputRange {
    type Err = ParseError;

    fn from_str(input: &str) -> std::result::Result<Self, Self::Err> {
        lazy_static! {
            static ref RE: Regex = Regex::new(r"(\d+)-(\d+)").unwrap();
        };
        let parse_error_msg= "Could not parse input range";

        let captures = RE.captures(input).unwrap();

        let low = captures.get(1).map_or("", |m| m.as_str())
            .parse::<u32>()
            .expect(parse_error_msg);
        let high = captures.get(2).map_or("", |m| m.as_str())
            .parse::<u32>()
            .expect(parse_error_msg);

        Ok(InputRange { low,  high })
    }
}