Extension methods

#rust

Square extension on numbers

mod foo {
    pub trait SquareExt {
        type Out; // Associated type
        fn square(self) -> Self::Out;
    }

    use std::ops::Mul;
    impl<T> SquareExt for T
    where
        T: Mul + Copy,
    {
        type Out = <T as Mul>::Output; // Using Mul's associated type
        fn square(self) -> Self::Out {
            self * self
        }
    }
}

fn main() {
    use foo::SquareExt;
    let a = 10.square();
}