perl

Most computer programmers have heard of regular expressions, discussed in hushed tones and conjuring images of Unix gurus and their incomprehensible commands and godlike mastery of their systems, yet few actually know enough about regular expressions or how they work to do more than a simple word match using one, if that.

This book covers regular expressions from top to bottom in great and exhaustive detail, including the hows and whys of performance and supported features between the different engines that process them. Though geared mainly toward Perl, the examples and text will apply to nearly any system that provides support, from PHP to ASP to Python.

The text is fairly dense and is not exactly geared toward the novice programmer, though. I've had classes in Finite State Machines and still had to really apply my grey matter in a few spots to understand everything being discussed. However, the understanding the reader gains upon completion of the text is invaluable and will expand one's programming potential exponentially.

The one real lack of the book is a good overview and quick-reference card, but on the whole, the book is a good selection from the O'Reilly library and well worth the read of any serious programmer.

I bought this book on a whim, mainly because I try to buy (and read... ugh!) a hard-core technical book every month or so, but mainly because my UNIX scripting abilities have become rusty with disuse. I used to be able to write a tight, 10-line csh script to mangledit thousands of files at a single time. Now I hack away at files manually with vi. The other day, I even forgot how to search & replace. My kung fu isn't nearly what it used to be.

It usually takes me about a month to slog through a new book (especially academic texts, which are great but make you want to have a stiff martini before each new chapter) but I tore through Friedl's book in a few days. It's an outstanding reference for understanding & learning to use regular expressions.

Regexes can be cryptic to say the least, but Friedl offers many examples, broken down into step-by-step instructions and explanations of how each regex works (in many cases, right down to the individual character level). He covers a variety of platforms and languages - the hardcore Perl enthusiast will enjoy this book greatly, but he offers fairly equal time to alternative languages like Java and the "grep" family.

All that said, this book is an outstanding technical reference, pure and simple, for two reasons:

- Friedl uses an interesting new typesetting convention to illustrate which sections of text are regular expressions, and which sections are not. It's hard to describe (and impossible to reproduce here) but they look like 90-degree braces at the upper-left and lower-right corners. This is a FANTASTIC approach and I for one would love to see this extended to other technical books.

- Speaking of other things I would love to see extended to other technical books, THIS BOOK HAS ALMOST NO ERRORS! This is even more impressive considering the fact that, with regular expressions, screwing up EVEN A SINGLE CHARACTER is significant. Nothing [upsets]memore than spending $50-100 perfectly good dollars on a sloppy, error-laden, grammatically-challenged, poorly-edited, ill-reviewed and badly-structured book (which pretty much describes 90% of all the technical books out there). He made a few mistakes, the vast majority of which are extremely trivial in nature, and all of which were quickly posted to his website as errata. If only the other 90% of the technical authors out there were even half as diligent.

All told, this book belongs on your bookshelf.

One of the hardest things, even for a seasoned programmer to grasp is regular expressions. They are powerful ways to search, manipulate and parse text fields and can often take several lines of code and shrink it down to a mystic, but powerful, expression.

If you have ever had to parse a file for information, you know that one of the things that still haunts any programmer nowadays is how to match text. In this day and age of Object Oriented Programming, Web Services, etc. the power of Regex holds firm.

Throughout this book the author takes great care not to overwhelm the reader with tons of code that has no meaning. The power of the book comes from the fact that if you read, and follow along, through the examples you will gain an understanding of how to do the techniques the author is referring to. At times it may seem like you have to read over a section twice, but you will realize that as you carry forth into the next section the material you read previously has turned into something you can now apply -- not just another example you can cut and paste and never really learn technique behind.

This is a powerful book, covering many, many pages. Noone should expect to sit down and read it cover to cover and be done with it. The benefit comes from reading, applying, and referencing. I find myself using it several times a week to lookup information on Regular Expressions and to held solidify knowledge of techniques that I have used in the past.

Whether you are a Windows, Unix, or even Macintosh person -- RegEx holds the key to text manipulation -- and this book holds the map you need to find that key.