BC: Do you ever look at your own code and think, "What the hell was I doing here?"

    AW: No, I guess I don't.

Of course, maybe he was answering the first 8 words.

http://queue.acm.org/detail.cfm?id=1531242

Logically, he could be answering the entire question truthfully, except that he doesn't look at old code at all. He'a clearly somebody very focused on the current "working set", with his rewrites and one-page files. As opposed to the kind of programmer who curates a sprawling historic code base.

Well, he does have to maintain it (apparently it needs a lot of bugfixes, according to discussion on Reddit) but, unlike the notorious perfection and immutability of the syntax of APL, he does have a habit of throwing old code away.