trait_interface.rs

trait Logger {
    fn log(&self, s: &str);
    fn err(&self, e: &str);
}

struct StdoutLogger {}

impl Logger for StdoutLogger {
    fn log(&self, s: &str) {
        println!("{}", s);
    }
    fn err(&self, e: &str) {
        self.log(e);
    }
}

fn run(l: &dyn Logger) {
    l.log("Hello");
    l.err("Oops");
}

fn main() {
    let l = StdoutLogger {};
    run(&l);
}