How to execute callback functions?

programming flash
1

Hi,

How do I execute callback functions dynamically by passing a function in as an argument to another function?

Look at this example:

package {

public class myClass extends MovieClip {

   public function myClass(callback) {

      this.addEventListener(MouseEvent.MOUSE_UP, mouseUp);

   }

   private function mouseUp(e:MouseEvent) {

      var x = 55; // do some calculation
      // execute callback funtion here with x as an argument

   }

}
}

How do I do this?