lvicentesanchez

trait Empty {
    fn empty() -> Self;
}

trait Semigroup {
    fn append(&self, other: Self) -> Self;
}

trait Monoid : Semigroup+Empty {}

lvicentesanchez

// Simple module type...
//
trait Ordering {
  type T

  def cmp(a: T, b: T): Int
}

// ...and implementation
//