main.rs

fn main() {

    fn output<F: Fn(String)>(text: &str, strategy: F) {
        let string = String::from(text);
        strategy(string)
    }

    // define strategies as closures
    let bold = |s| println!("<strong>{}</strong>", s);
    let italics = |s| println!("<em>{}</em>", s);
    let header = |s| println!("<h1>{}</h1>", s);

    let text = "This is a test.";

    // call output using each strategy
    output(text, bold);
    output(text, italics);
    output(text, header);

}