I find it more than a little disturbing that the first time you really used C was to figure out the PHP interpreter. It's among the worst C code I've ever seen (aside from code I've seen on dailywtf). After I had to debug something in the PHP interpreter, I refused to have anything to do with PHP ever again.

Anyway I hope for your sake looking at the Python interpreter did more than reinforce your knowledge. It's no stroke of genius, but it's much better written than PHP.