struct Parsed<'a> {
    parts: Vec<&'a str>,
}

impl<'a> Parsed<'a> {
    fn parse(s: &'a str) -> Self {
        let parts = s.split_whitespace().collect();
        Parsed { parts }
    }

    fn len(&self) -> usize {
        self.parts.len()
    }

    fn parsed_len(s: &str) -> usize {
        Self::parse(s).len()
    }
}

fn process<F: Fn(&str) -> usize>(f: F) {
    //unimplemented!()
}

fn main() {
    process(Parsed::parsed_len)
}