anchor.diff:  // Copyright (c) 2012, Lukas Renggli <renggli@gmail.com>
  +
  +/** Function interface for parse actions. */
  +typedef Dynamic Action(Dynamic argument);
   
   /**
    * A parser that performs a transformation with a given function on the
  
positive.code:     }
      return LINEFEED_PARSER;
    }
  }
  
  /** Non local return. */
  class NonLocalReturn<T> implements Exception {
    final T _value;
    NonLocalReturn(this._value);
    T get value() => _value;
  }
negative.code:  */
  class ActionParser extends DelegateParser {
  
    final Action _function;
  
    ActionParser(parser, this._function) : super(parser);
  
  