//$use Dos StdIO; //TIMER;
$use StdIO;

$func  MkArg  eString = ePrefixes;
$func  Select (eXs) eSets = eXs-or-sFail; * (eXs) or '*'
$func? Sel    (eXs) eSets = (eXs);

Main =
  /*<PrintLN <Time>>,*/ 
  <MkArg '1234567890ab'> :: e.Arg,
  <PrintLN e.Arg>,
  <Select () e.Arg> :: e.Res,
  <PrintLN e.Res>,
  /*<PrintLN <Time>>*/;

MkArg e.String = * e.Prefixes
  ( ) (e.String) $iter {
    e.Prefix : e.Prefix-- s =
      (e.Prefixes (e.Prefix)) (e.Prefix--) ;
  } :: (e.Prefixes) (e.Prefix),
  e.Prefix : /*empty*/
   = e.Prefixes;

Select (e.Xs) e.Sets = * e.Xs-or-sFail -- (eXs') or '*'
  {
    <Sel (e.Xs) e.Sets>;
    '*';
  };

Sel (e.Xs) e.Sets = * (eXs) | $fail;
  e.Sets : \{
    /*empty*/ = (e.Xs);

    (e.Set) e.Sets--,
      e.Set : e sX e, 
      # \{ e.Xs : e s.X e; },
      <Sel (e.Xs sX) e.Sets-->;
  };