anchor.diff:  ''')
   
   class Clock{
  -  int startAt = (25*60);
  -  String counter='25:00';
  +
  +  int startAt;
  +  String durationBreak;
  +  String counter;
     Stopwatch watch = new Stopwatch();
     Timer timer;
  +
  +  Clock(){
  +    startAt = (25*60);
  +    durationBreak = prettyPrintTime(5);
  +    counter= prettyPrintTime(25);
  +  }
     
     void start() {
       watch.start();
  
positive.code: 
  @View(template: '''
  <p>Clock: <i>{{ counter }}</i></p>
  <p>Start at: 
  <input #userstartat>
  <button (click)="setStartTime(userstartat.value)">set time</button>
  </p>
  <button (click)="start()">Start</button>
  <button (click)="stop()">Stop</button>
  
negative.code:   }
  
    void setStartTime(string at){
      var value = int.parse(at, onError: (source) => null);
      if (value != null){
        startAt = value*60;
      }
    }
  
    void setDurationBreak(string d){
      var value = int.parse(d, onError: (source) => null);
      if (value != null){
        durationBreak = prettyPrintTime(value);
      }
    }
  
    String prettyPrintTime(int s){
      s = s * 60;
      var m = 0;
      
      // The operator ~/ divides and returns an integer.
      if (s >= 60) { m = s ~/ 60; s = s % 60; }
      
      String minute = (m <= 9) ? '0$m' : '$m';
      String second = (s <= 9) ? '0$s' : '$s';
      return '$minute:$second';
    }
  }