ActionScript 3.0 :: "toString" Returns A String - More Classes?

It seems as thought whenever you try to treat a class as a String (such as putting it inside of trace() or similar), if that class has a "toString" function, it will get the string from whatever that function returns, and will otherwise return something along the lines of "[object MyClass]".

Are there any more of these special functions?

Also, a bit of a far stretch, is there any way to do this with custom classes, for instance, your class may be a PolarPoint, but people can call "toLinearPoint()" and get an instance of a class which is a LinarPoint but with the same data.

Now, this is simple enough to do manually, but let's say you pass in the PolarPoint in a function where a LinearPoint is expected. Is it possible to make Flash automatically run the toLinearPoint() function if found? Similar to how Flash will run toString automatically if passed in as a String somewhere.

That second part is probably more of a hassle than it is worth though, but it would be REALLY handy if you are unable to extend two classes at once, but want your class to be able to be treated as both.