Next Generation Regexp

prostoalex writes "Jeffrey E. F. Friedl, author of newly published 2nd edition of Mastering Regular Expressions, wrote a feature article for O'Reilly Network on the recent innovations in the regular expression world. You'd think that such area as regular expressions would be fairly stable, but according to the author, 'when I started to work on the second edition of Mastering Regular Expressions and started refocusing on the field, I was rather shocked to find out how much had really changed'. The article's behind-the-scene purpose is apparently to push a new book that O'Reilly published this month, but it has great educational value for anyone involved with practical extracting and reporting."

Comments

Friedl's book is a must read for Perl folks

[Lumpish Scholar]

It's not just a Perl book, but the language independent and Perl dependent parts are a godsend.

I was a full time Perl programmer (with a two hour commute by rail) when Friedl's book came out. I read it cover to cover, and then recommended it strongly to my co-workers.

Friedl shows how to write powerful, readable, efficient regular expressions that can do a lot of the work your program needs to do. It changed how my group wrote Perl (very much for the better). This is more than highly recommended; after the Blue Camel, and even before the Cookbook, this is a definitive book for all those who call themselves "Perl programmers."

(In the first edition of the book, Friedl discovered some problems with regular expressions in early versions of Perl 5. The very next release of Perl -- 5.003, I think -- immediately fixed these problems. When Larry & Co. pay attention to a Perl book, maybe you should, too?)

Re:Contentless article

[Get Behind the Mule]

That is one of the most contentless articles I have seen in a long time.

A regex is a type 3 grammar. Type 3 grammars haven't really changed since Chomsky's time.

You get a B-, Bunky. And here's your cookie.

After you've finished your untergrad CS theory class, you might go on to discover that implementations of regexes under various paradigms and in the various languages have extremely rich variety regarding syntax, semantics and efficiency. This isn't about the pristine theory of Prof. Chomsky, but about the actual use of regexes as programming constructs, and that's a tremendously complex subject. Friedl's book in the first edition is one of the best I've ever seen that has tackled such complexity and made it accessible and useful for the everyday business of programming.

The article indicates that the practical use of regexes, far from stagnating since Chomsky's time, continues to evolve and grow. That's only "contentless" if you're stuck in the ivory tower and don't intend to leave.