Pro Perl Parsing (Hardcover)

by Christopher M. Frenz (Author)
Key Phrases: reduce using rule, math parser, parsing tasks, Christopher Frenz, Apress Web, Pro Perl Parsing (more...)

Editorial Reviews

Product Description
I thoroughly enjoyed this...I write and maintain a fair amount of Perl, and matching and parsing patterns is often the largest part of the work.</a></p> </blockquote> <p id="quoteAuthor">&#8212; A.P. Lawrence, Information and Resources for Unix and Linux Systems</p></div>

<p>Perl, one of the world's most diffuse programming languages, was born out of the need to resolve the creator's dissatisfaction with what were at the time standard data-parsing solutions. Indeed, since the 1.0 release in 1987, Perl has been heralded for its powerful parsing capabilities&emdash;features that are further enhanced through the thousands of Perl extensions made available through CPAN (the Comprehensive Perl Archive Network).</p>

<p><i>Pro Perl Parsing</i> begins with several chapters devoted to key parsing principles, discussing topics pertinent to regular expressions, parsing grammars, and parsing techniques. This material sets the stage for later chapters, which introduce numerous and powerful CPAN parsing modules, and provide an ample supply of example applications.</p>

About the Author
Christopher Frenz is a bioinformaticist at New York Medical College and is the author of <i>Visual Basic and Visual Basic.NET for Scientists and Engineers</i>. Frenz is an expert in Perl and scientific programming, in addition to the .NET platform.

Product Details

• Hardcover: 272 pages
• Publisher: Apress (August 10, 2005)
• Language: English
• ISBN-10: 1590595041
• ISBN-13: 978-1590595046
• Product Dimensions: 9.3 x 7.1 x 0.9 inches
• Shipping Weight: 1.4 pounds (View shipping rates and policies)
• Average Customer Review: 4.2 out of 5 stars See all reviews (9 customer reviews)
• Amazon.com Sales Rank: #698,609 in Books (See Bestsellers in Books)

Customer Reviews

Most Helpful Customer Reviews

13 of 13 people found the following review helpful:

3.0 out of 5 stars Would have expected more, December 28, 2005

By	Michael Schilli (San Francisco, CA USA) - See all my reviews (REAL NAME)

The first 108 pages of "Pro Perl Parsing" deal with basic parsing concepts and give examples on how to use a CPAN module to define parsers. It's not quite accurate at times, though: The author uses the terms 'precedence' and 'associativity' interchangably, although these are orthogonal concepts. And the parser on page 82 has a design flaw (hint: try parsing "(5*(3+4))+1)", which yields 40, ouch!).

Then come 30 pages with a manual-page style explanation of Damian Conway's Parse::RecDescent module, along with some interesting tidbits here and there.

However, I would have expected to read a better explanation of the underlying parsing theory, like a distilled and simplified version of the "Dragon" book (Aho, "Compilers"). I would have liked to read how to write a custom parser from scratch in Perl, like in Mark Jason Dominus' "Higher Order Perl". Also, I would have expected more practical examples on how to tackle common parsing problems.

However, the second half of the book starts with an explanation of the HTML language. We get to know how titles and lists and links are done in HTML. Then we learn how to fetch web pages with Perl. Also, we learn about web services via SOAP and XML-RPC, about formatting output in Perl and are getting a chapter on "data mining". These topics aren't related to "parsing" at all, though.

There's an example on page 202 on how to parse command line arguments by lumping them all together to form a single string and then firing up an expensive recursive descent parser to tear them apart. Experienced Perl programmers would solve this common problem elegantly in a single line of Perl, using the Getopt::Std module.

So, I'm somewhat ambivalent on this book. Since there's not many books on Perl parsing, I was excited about it, but I was somewhat disappointed by the lack of depth, accuracy, and the filler-style second half of the book. I would have liked to read more about parsing in Perl and less about how to use CPAN modules dealing with parsing-related topics. Had the book maintained a strong focus on plain "parsing", it could have been a slam-dunk five-star. So, it's only three -- worth reading, but not a potential classic.

4 of 4 people found the following review helpful:

5.0 out of 5 stars An excellent primer on parsing, September 4, 2005

By	David DelGreco (Bay Area, CA USA) - See all my reviews (REAL NAME)

This is a great book on parsing for novices that goes over the different kinds of parsing tasks, looks at the different tools available, and gives numerous examples. It's also a great book for experienced Perl programmers who have limited experience with parsing, other than Text::CSV_XS and regexes. The most time is spent on Parse::RecDescent, the most popular parsing module for Perl, but it doesn't give others, like Text::Balanced and Parse::YAPP, short shrift. Later, he gives excellent help on parsing HTML and XML, and in the final chapters he introduces text and data mining. Quite an education!

So whether you have to parse structured or semi-structured text, you want to build yourself a little command language, you need to scan gobs of web or other documents for information, or have any parsing task where your regexes are just getting out of hand, then check out this book.

P.S. I don't know what psychoactives the first reviewer had consumed, but this book is not about "medical-text processing in particular," or even generally. It could be used for that, but it is a general, intermediate-to-advanced book on parsing with Perl. If you were thinking of buying it, it is what you think it is, and not what Dr. Oscar thinks it is.

5 of 6 people found the following review helpful:

5.0 out of 5 stars Very techincal but just what I was looking for, September 17, 2005

By	Harold McFarland (Florida) - See all my reviews (TOP 50 REVIEWER)    (REAL NAME)

Wow! I do a lot of data parsing and this book is one of the best finds I have ever made. I should point out, however, that it is not for the average reader. This book is very technical in nature but absolutely fabulous if you are technically inclined or already proficient in Perl or have some experience parsing using another language. It seems that I am always finding strange problems that create a need to parse large amounts of data to extract only the relevant information and present it in a usable form. Author Christopher M. Frenz covers the whole gamut of parsing and does so in a very logical progressive manner. First he starts with the use of regular expressions and does a great job including some complex example of just what can be done. From there he moves to generative grammars and how they can be used to determine relevant data of interest within a text, XML or similar file. Then from there he builds on your understanding by discussing specialized modules that can be added to your Perl implementation and how they are used. And, of course, he discusses data mining and how to efficiently use this information. This is an excellent technical book that is a required resource for anyone using Perl to parse documents. Pro Perl Parsing is highly recommended.