//$use Dos StdIO; //"timer";
$use StdIO;

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

Main =
  /*<PrintLN <Time>>,*/
  <MkArg '1234567890ab'> :: e.Arg,
  <PrintLN e.Arg>,
  <Select () e.Arg> :: e.Res,
  <PrintLN e.Res>,
  //<Timer-BegProc " End ">::t,
  /*<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 '*'
  e.Sets : {
    /*empty*/ = (e.Xs);

    (e.Set) e.Sets--,
      e.Set : e sX e, 
      #<OneOf (e.Xs) sX>, 
      <Select (e.Xs sX) e.Sets--> : (e.Xs-) = (e.Xs-);

    e = '*';
   };

OneOf (e.Xs) s.X = */
   e.Xs : e s.X e;