fn swap*[T](s: &mut []T, a: uint, b: uint) unit = unsafe {
    let pa = s.ptr + a
    let pb = s.ptr + b
    pb.0 = pa.0 := pb.0
}

fn reverse*[T](s: &mut []T) unit = {
    let mut i = 0
    let mut j = s.len - 1

    for if i < j {
        s.swap(i, j)
        i += 1
        j -= 1
    }
}