monads in rust (1st attempt)

gistfile1.rs

trait Monad<A> {
	//fn bind<B>(&self, &fn (b: B) -> Self) -> Self;
	fn ret(a: A) -> Self;
}

enum Zoption<T> {
	ZSome(T),
	ZNone
}

impl<T> Monad<T> for Zoption<T> {
	fn ret(a: T) -> Zoption<T> {
		ZSome(a)
	}
}

fn main() {
	let opt = Monad::<int>::ret::<Zoption<int>>(5);   // does not compile
	match opt {
		ZNone => println("This is none"),
		ZSome(y) => println!("Some({})", y)
	}
}