$use Arithm "RF_Stack" StdIO;

$func F = ;
$func F1 s = ;
$func F2 s s = ;
$func F3 s s s = ;

F3 s1 s2 s3 = <F2 s2 s3>, <Write>;
F2 s1 s2    = <F1 s2   >, <Write>;
F1 s1       = <F       >, <Write>;

F = 0 $iter <"+" s.offset 1> :: s.offset,
  {
    $trap <WriteLN <Args <"-" <Depth> s.offset>>>, Continue
    $with {
      e = <WriteLN <Depth>>, Break;
    };
  } : Break;

Main = <F3 A B C>;