let data: buffer? = try GET("whatever.json");

if (cmd == "s") {
    clear_screen();
    print("Shoot where? ");
    handle_shot();
  } else {
    var room_num := Number::cmd;

    if (room_num == Symbol(CAST_FAILED)) {
      clear_screen();
      print("Don't know what that is.");
    } else {
      print("Move: " + room_num);
      var rest = Number::(IO.prompt(""));

      if (rest == Symbol(CAST_FAILED)) {
        continue;
      } else {
        clear_screen();
        handle_move(room_num * 10 + rest);
      }
    }
  }

for (var i = 0; i < blah.length; i++) {
   //..
}
// is equiv to
while (i < blah.length)

a success
 i _
 d _
 success

a zero
 d 1
 zero 1
 success

# take <x> <y>
# sets <x> to <x> + <y> and <y> to <0>
a take
 d 2
 take_2 1 2
 success
a take_2
 i 1
 take 1 2
 success

# swap <x> <y> <temp>
a swap
 zero 3
 swap_2 1 2 3
 success
a swap_2
 take 3 1
 swap_3 1 2 3
 success
a swap_3
 take 1 2
 swap_4 1 2 3
 success
a swap_4
 take 2 3
 success
 success