I've been using ANTLR for parsing Java source code and some other things lately. Its cool but a bit weird. The cool bit is you can embed bits of java source code on the RHS of parse rules to do nifty things.

But the rule syntax itself is freaky.

So I get the idea behind this philosophy and I know it has power. It will be interesting to see what people do with it.

Sadly, Java has just set their regex package in stone forever.