Simple Method Closure in AS3
DIGG IT!
Published
Friday, January 15, 2010
at
3:23 PM
.
Method closures allow you to bind variables into the scope of an anonymous function. Watch the value of local variable 'i' in the example below in the returned anonymous function. It is a bit twisted but results show the scope of local variable 'i' is bound in the returned function from newCounter.CODE AT PASTIE
package
{
import flash.display.Sprite;
public class ClosureAS3 extends Sprite
{
public function ClosureAS3()
{
init() //giv-em-the-jit :)
}
public function init():void
{
//create a counter
var counter1:Function = newCounter();
trace( counter1() ); //1
trace( counter1() ); //2
trace( counter1() ); //3
var counter2:Function = newCounter();
trace( counter2() ); //1
trace( counter2() ); //2
trace( counter1() ); //4 --> scope of i is still with counter1...cool! :)
}
public function newCounter():Function
{
var i:int = 0; //variable i gets bound into returned anonymous function via method Closure
return function():int
{
//i is available to the scope of the anonymous function
i=i+1;
return i;
}
}
}
}
Scary, functional AS3. :)
Cheers,
Ted :)