anchor.diff:      return new Scope(map);
     }
   
  -  html.Element commandInput;
     html.Element userCanvas;
     html.Element turtleCanvas;
     html.Element commandListElem;
  
positive.code:   }
        
    void run() {
      //commandInput =  html.document.query('#command_input');
      //commandInput.on.keyPress.add(handleKeyPress);
      userCanvas = html.document.query("#user_canvas");
      var userCtx = userCanvas.getContext("2d");
      turtleCanvas = html.document.query("#turtle_canvas");
  
negative.code:     interpreter = new Interpreter(turtle, console, toplevel.extend());
      console.init(interpreter);
    }
  }
  
  void main() {
  