So there I am, writing my regex book. I document split() rather extensively, and then someone tells me I got it wrong. How disappointing.

So there I am, at TPC, listening to Damian Conway talk about "Data Munging" in his tutorial on Monday. He starts talking about split(), and I correct him. It turns out that I'm wrong (in the same way I was wrong in my book). So I've got two strikes.

One would think, at this point, I'd cash in my chips, correct the text in my book, and sink back into my cave. Nuh-uh.

Some people would fix their book to be consistent with the language. I fixed the language to be consistent with my book! Let me explain:

In Perl 5.005_02, split /(A)|B/, "1A2B3" returned a five-element list of (1, 'A', 2, undef, 3). In 5.005_03, it returned (1, 'A', 2, '', 3); a subtle, but meaningful, difference. There's only one way to get an undef from split(), and that's from the underlying regex match. A capturing paren that does not match has undef as its $DIGIT value.

A tiny bit of incorrectly written code in pp.c:pp_split() caused these undefs to become empty strings. Bah. I corrected it, documented it, and tested it.

So that's my story of being a pretentious bastard, and insisting Perl work the way I think it should (and the way it worked before, and that makes more sense, and that is now tested and documented).

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Jeff japhy Pinyan: Perl, regex, and perl hacker.
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