Actionscript 3 :: Getting The Value Of A Property Within Another Property Via Square Bracket Notation

I have a class Inhabitant with a property skin which is of type DisplayObject.

Within Inhabitant I need to access the x and y properties of skin using this method:

this["someProperty"];
Rather than:
this.someProperty;

This is fine with properties defined within Inhabitant but I'm not sure how I could do this for a property of skin. This obviously doesn't work but it might give you an idea of what I'm trying to do:

this["skin.x"];

The reason behind requiring this notation is that I have a function which I can parse a String though that will represent a property:

public function addTokenable(property:String):void
{
if(!isTokenable(property))
_tokenables[property] = true;
}

And then a related getter that will return a representation of this instance of Inhabitant as a String:

public function get token():String
{
_token = "class:" + getQualifiedClassName(this).split("::").join(".");

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