anchor.diff:      WITH = _token('with');
   
       // built-in identifiers
  -
       ABSTRACT = _token('abstract');
       AS = _token('as');
       DYNAMIC = _token('dynamic');
  
positive.code:       .seq(string('*/')));
    }
  
    /** Defines a token parser that consumes whitespace. */
    Parser _token(input) {
      var parser = input is Parser ? input :
        input.length == 1 ? char(input) :
  
negative.code:     DEFAULT = _token('default');
      DO = _token('do');
      ELSE = _token('else');
      ENUM = _token('enum');
      EXTENDS = _token('extends');
      FALSE = _token('false');
      FINAL = _token('final');
  