anchor.diff:     *
      * Please use [Direction]'s static members for the input.
      */
  -  void moveSetDirection(String direction) {
  +  void moveOneDirection(String direction) {
       directionSystem.setMainDirection(direction);
     }
   
  -  //TODO: doc
  +  /**
  +   * Moving the sprite by a given distance.
  +   */
     void moveBy(String direction, {int distance: 5}) {
       StageXL.Vector directionVector = directionSystem.getDirection(direction);
   
  
positive.code:         (y + directionVector.y * distance).round());
    }
  
    //TODO: doc
    void moveTo(int x, int y) {
      directionSystem.setMainDirectionFromTo(
          this.x.round(),
  
negative.code:     }
    }
  
    bool _speedOverEqualMaxSpeed() {
      return (speedX >= maxSpeed || speedY >= maxSpeed);
    }
  
    bool _speedUnderEqualMinSpeed() {
      return (speedX <= minSpeed || speedY <= minSpeed);
    }
  
    void _checkSpeedLimits() {
      if (_speedOverEqualMaxSpeed() && _accelerationDirection == 1) {
        _accelerationDirection = 0;
  