This[] and MainTimeline(parent)

Question

Let's say I have several buttons in a movie clip named firstVar, secondVar, thirdVar which all call the same function when you click on them. The main timeline has three variables also named firstVar, secondVar, thirdVar. I am trying to use evt.target.name in my function so that clicking on the button references the proper variable in the main timeline.
function myFunction(evt:MouseEvent):void {
          trace(MainTimeline(parent).firstVar);
          var test:String = "MainTimeline(parent)." + evt.target.name;
          trace(test);
          trace(this[test]);
          trace(this["MainTimeline(parent)." + evt.target.name]);
Here's the output window after clicking on the firstVar button:
1
MainTimeline(parent).firstVar
undefined
undefined
The first trace produces the correct value of firstVar. The second trace shows that the concatenation of "MainTimeline(parent)." and evt.target.name works. In the third and fourth traces it shows that this[] fails to get the proper value. Does anyone know why and how to make this work?

Answer 1

that's a really bad choice of variable (or movieclip) references.  they must be in different scopes or you should see runtime errors but even so that's poor coding.
assuming those are in different scopes, use:
MovieClip(root)[evt.target.name];
to reference the variables:
function myFunction(evt:MouseEvent):void {trace(MovieClip(root)[evt.currentTarget.name]);}