fun map (f, l) {
  case l of
    {}     ->  {}
  | h : tl ->  (f (h) : map (f, tl))
  esac
}

fun a (x) { x + 1}
fun b (x) { x + 2}

fun print_list (x) {
  case x of
    {} -> skip
  | h : tl -> write (h); print_list (tl)
  esac
}

var x = read ();

print_list ({1, 2, 3});
print_list (map (a, {1, 2, 3}));
print_list (map (b, {1, 2, 3}))