anchor.diff:      ;
   
   fragment
  -LIDENTIFIER :;
  +LIDENTIFIER
  +    :   LIdentifierPrefix name=IdentifierPart+
  +        {$text = $name; /* FIXME this is unlikely to work */ }
  +    // also see UIDENTIFIER    
  +    ;
  +
   fragment
   PIDENTIFIER :;
   fragment
  
positive.code:           //TODO: error!
          } }
      ;       
               
  fragment 
  IdentifierPart
      :   '_'
  
negative.code:     :   IdentifierStart IdentifierPart*
          { int cp = $text.codePointAt(0);
            if (cp=='_' || Character.isLowerCase(cp)) $type=LIDENTIFIER; }
      |   UIdentifierPrefix name=IdentifierPart+
          { $text = $name; /* FIXME this is unlikely to work */ }
      ;
  
  fragment
  