let test =
    let x = ref 5;
    let y = ref 0;
    let z = ref 5;
    while (!x >? 0) {
      x := !x - 1;
      while (!z >? 0) {
        y := !y + 1;
        z := !z - 1
      };
      y := !y + 1
    };
    if (!y =? 10) then {
      print_string ("This test is OK!\n")
    } else {
      print_string ("This is KO!\n")
    }