anchor.diff:  }
   
   @deprecated
  +typedef void PluggableCompositeParserCallback(CompositeParser self);
  +
  +@deprecated
   class PluggableCompositeParser extends CompositeParser {
  -  final Function _function;
  -
  -  PluggableCompositeParser(this._function) : super();
  +  final PluggableCompositeParserCallback _callback;
  +
  +  PluggableCompositeParser(this._callback) : super();
   
     @override
  -  void initialize() {
  -    _function(this);
  -  }
  +  void initialize() => _callback(this);
   }
   
   main() {
  
positive.code:     });
      test('token() on list', () {
        var parser = any().plus().token();
        var token = parser
            .parse([1, 2, 3])
            .value;
        expect(token.value, [1, 2, 3]);
  
negative.code:       var parser = digit().plus().token();
        expectFailure(parser, '');
        expectFailure(parser, 'a');
        Token token = parser
            .parse('123')
            .value;
        expect(token.value, ['1', '2', '3']);
  