anchor.diff:  import "dart:core";
   import 'package:clean_data/clean_data.dart';
   
  -//TODO consider moving to a separate file
   /**
    * [View] is responsible for manipulating data received from server to be used for HTML.
    * Methods of [View] are called when [PageNavigator] matches the corresponding route
    *   or when is navigated to different location.
    */
  -abstract class View{
  +abstract class View {
     /**
      * Called when [PageNavigator] decides a new [View] should be used/displayed.
      * [View] should listen do [data] changes.
  
positive.code: /**
   * Registers a [View] which is called when router does not find any match.  
   */
    void registerDefaultView(View view){
      this._defaultView = view;
    }
  
  
negative.code:     // Decode [url] parameters and fill them into [Map].
      Map result = new Map();
      for (var i = 0; i < _variables.length; i++) {
        result[_variables[i]] = Uri.decodeComponent(match.group(i + 1));
      }
  
      return result;
  