You should definitely read the Regex chapter in the Camel book. It's a tough slog - took me about 10 rereads to finally get it. But, it's extremely worth it. I'm no regex master by any measure, but understanding that chapter went a long way to getting me fluent in Perl.
My criteria for good software:
- Does it work?
- Can someone else come in, make a change, and be reasonably certain no bugs were introduced?