anchor.diff:        .seq(string('*/')));
     }
   
  -  /** Defines a token parser that consumes whitespace. */
  +  /** Helper to define a token parser that consumes whitespace. */
     Parser _token(input) {
       var parser = input is Parser ? input :
         input.length == 1 ? char(input) :
  
positive.code:     _libraries();
    }
  
    /**
     * Defines whitespace, documentation and comments.
     */
    void _whitespace() {
      def('whitespace', whitespace()
        .or(ref('singe-line comment'))
  
negative.code:     WITH = _token('with');
  
      // built-in identifiers
      ABSTRACT = _token('abstract');
      AS = _token('as');
      DYNAMIC = _token('dynamic');
  