Method parse_operator

examples/block4.rs:231–237

(token: &str)

impl Element {
    fn parse_operator(token: &str) -> Option<Self> {
        match token {
            "&&" => Some(Self::And),
            "||" => Some(Self::Or),
            _ => None,
        }
    }

    fn is_operator(token: &str) -> bool {
        Self::parse_operator(token).is_some()