anchor.diff:     (WS)* R_PAREN
   
      {
  -      /* TODO */
         $result = ($a.result).implies(($b.result));
      }
   ;
  
positive.code:    (WS)* R_PAREN
  
     {
        /* TODO */
        $result = ($a.result).implies(($b.result));
     }
  ;
  
negative.code:    (WS)* R_PAREN
  
     {
        $result =
           (
              ($bl_formula.result)
  