Hey, Mmilano.
I know I'm off on a tangent here, but I was wondering if you had done any XML using PHP? Assuming you had a good routine for building the XML document, you could navigate it using the DOM methods. Using XML is probably more overhead than what I wrote (

), but I thought this would be an interesting way of handling the problem.
I still prefer java for this sort of thing. You can use javabeans to load your tree into the session so that you only have to read it from disk once. (assuming you're not updating it in your app) Just a little java plug.

Speaking of which, I should start on that NUM I wanted to write.