stack_edsl.rs

fn pop<T, ..Stack>((_, ..stack): (T, ..Stack)) -> Stack {
    stack
}

fn dup<T: Clone, ..Stack>((x, ..stack): (T, ..Stack)) -> (T, T, ..Stack) {
    (x.clone(), x, ..stack)
}

fn swap<T, U, ..Stack>((x, y, ..stack): (T, U, ..Stack)) -> (U, T, ..Stack) {
    (y, x, ..stack)
}

fn eq<T: Eq, ..Stack>((x, y, ..stack): (T, T, ..Stack)) -> (bool, ..Stack) {
    (x == y, ..stack)
}

fn add<T: Add<T, T>, ..Stack>((x, y, ..stack): (T, T, ..Stack)) -> (T, ..Stack) {
    (x + y, ..stack)
}

fn mul<T: Mul<T, T>, ..Stack>((x, y, ..stack): (T, T, ..Stack)) -> (T, ..Stack) {
    (x * y, ..stack)
}

fn square<T: Clone + Mul<T, T>, ..Stack>(stack: (T, ..Stack)) -> (T, ..Stack) {
    mul(dup(stack))
}

#[test]
fn test(){
    assert_eq!(pop((4, 2)), (2,));
    assert_eq!(dup((3,)), (3, 3));
    assert_eq!(swap((4, 2)), (2, 4));
    assert_eq!(eq((4, 2)), (false,));
    assert_eq!(eq((4, 4)), (true,));
    assert_eq!(add((4, 2)), (6,));
    assert_eq!(mul((4, 2)), (8,));
    assert_eq!(square((3,)), (9,));
}