Traits

Rust lets you abstract over types with traits. They're similar to interfaces:

struct Dog {
    name: String,
    age: i8,
}
struct Cat {
    lives: i8,
}

trait Pet {
    fn talk(&self) -> String;

    fn greet(&self) {
        println!("Oh you're a cutie! What's your name? {}", self.talk());
    }
}

impl Pet for Dog {
    fn talk(&self) -> String {
        format!("Woof, my name is {}!", self.name)
    }
}

impl Pet for Cat {
    fn talk(&self) -> String {
        String::from("Miau!")
    }
}

fn main() {
    let captain_floof = Cat { lives: 9 };
    let fido = Dog { name: String::from("Fido"), age: 5 };

    captain_floof.greet();
    fido.greet();
}