Calling functions dynamically AS2-AS3 Nightmare

Hi all,
First of all let me state my position as a designer first and coder second (probably third or fourth if the truth be known). This does not mean that I hate code, its just that I code on a needs basis. Even so I have managed to put (cobble) together some quite interesting things using AS2 and would say that I was comfortable and even moderately proficient with it.

However I have just tried to take the step up to using AS3 and Im dumbfounded. Where’s everything gone?

It was bad enough realising almost the entire way of doing things would have to change, but to then find that the documentation seems to assume a level of knowledge of coding structure, practices and methods that are so far beyond me that I feel like Im learning from scratch.

Now that Ive had my rant, here’s my problem…
In AS2 this worked fine:

 
function moveClip(){
 myClip._x+=20;
}
functionName=eval(moveClip());
eval(functionName);

How do I achieve the same thing with AS3?

(I know that there are those amongst us that frown upon using the eval function but it works for me and I wasnt aware of an alternative until recently.)