$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   >;
F1 s1       = <F       >, <Write>;

F = <WriteLN <"RF_Stack" 1 0>>,
  $error "Error in <F>";

Main =
  $trap <F3 A B C> $with {
    e1 =
      <Print "Catched: "> <WriteLN e1>,
      <WriteLN <Trap-Stack>>;
  };