text: -- Zoo9 from notes.org. Choice order is important
  
  def Main = {
      a = Match1 ('0'..'9');
      b = Match1 ('0'..'9');
      c = Choose { 
          { b < '5' is true; ^ '5' }; 
          { ^ '1' }; 
      }; 
      c == '5' is true;
  }
  