Perl Medic

Craig Maloney writes "Anyone who codes in Perl can relate to working on other people's code. Sometimes the code will thankfully include "use warnings" and be a joy to maintain. More likely, though, the code will have so many warnings that the useful output is long gone in the stratosphere of your scroll buffer. Even good code written for earlier versions of Perl can become aged and decrepit, requiring elderly modules that may or may not work with newer versions of Perl. Maintaining this code can be a hassle, but fortunately Perl Medic: Transforming Legacy Code (referred to for the duration of the review as Perl Medic) provides some very useful tips for getting through these migrations, and will help the next person maintaining your code." Read on for the rest of Maloney's review. Perl Medic author Peter J. Scott pages 312 publisher Addison Wesley rating 8 reviewer Craig Maloney ISBN 0201795264 summary A great collection of Perl wisdom and tips for experts and other patient Perl acolytes.

One of the goals of Perl Medic is to transform code from stylistically poor and unmaintainable into stylistically sound, maintainable and testable code. The format of Perl Medic is very similar to books like The Pragmatic Programmer or The Practice of Programming. Perl Medic shows the reader best practices by example. Some of the chapters are checklists of practices that will help improve your ability to manage and wrangle the code, while others are lists of patterns and practices you should avoid, and should replace with the examples provided. This format very readable, and provides an excellent forum for gleaning what ways to improve the code.

Perl Medic is designed with experienced coders in mind. Topics are presented as if the reader may be using these ideas already in their code, whether good or not. While the advice is good, the presentation may be confusing for beginner and intermediate programmers who aren't intimately familiar with the concepts. I found myself re-reading several topics to try and grasp what the author was trying to convey. After several readings of the section on test harnesses, I still needed help, and ran to the Perl documentation to better understand what the author was saying. Certain advice is also presented, only to have it countered in the next section. Most Perl programmers are familiar with the '-w' switch, which turns on warnings in a Perl program. The pragma 'use warnings' is introduced as a way to turn on warnings for just the code being worked on without displaying the warnings of the modules included in the program. In the next section, the author points out that it might be a good idea to put '-w' in there to see if there are any issues in the modules you may be including. While this advice may be intuitive for experienced Perl coders, the beginner may be confused. "Should I use '-w', or should I use 'use warnings'" she may ask herself.

The book also suffers from a case of being too brief in some sections. In section 2.3.1 (Gobbledygook) the reader is directed for help on how to turn a partially obfuscated program into more intelligible code; a very useful skill indeed. The author redirects the reader to section 4.5 where the utility perltidy is discussed with further detail, but before ending the section, the author also introduces the module 'B::Deobfuscate' along with a URL. No mention of how to use it is provided. In section 6.4 (Debugging Strategies) the author gives advice on how to debug a program. His advice: "Divide and Conquer". While there is debugging advice throughout the book, it's a little frustrating to see a section specifically designated "Debugging", with only one subheading under it. The organization of some of the topics feels artificial, and perhaps should be reorganized in future editions.

Underneath these faults, though, Perl Medic is a great book. Chapter 11 (A Case Study) should be required reading for coders inheriting Perl projects. This chapter is a blow-by-blow account of the author's work in transforming a simple LDAP application from Perl 4 into a robust Perl 5.8 application. The author is very candid about what decisions were made in the code transformation, and why certain elements were addressed in the way they were addressed. One particular element is an elderly module used for the LDAP lookups themselves. The author details the process used to determine a better module to replace this module, and guides the reader through each of the steps required to change the code to use this new module. The decisions the author uses to make this code work under the new environment are enlightening for anyone planning a migration of Perl code into a newer environment. Chapter 7 contains the versions of Perl from Perl 4 up until 5.8.3, and elaborates on what changed between the versions (very helpful for those who are planning an upgrade from 5.003 to a more recent version of Perl). Chapter 9 (Analysis) has very useful tips for not only debugging you program, but for using the Perl Debugger and getting the most out of your debugging session.

Perl Medic is recommended for anyone who is tasked with maintaining or writing Perl Code. While the examples are written with experienced coders in mind, beginners will do well to use this book for areas to focus on while they learn the language. Inheriting code can be a daunting task, but with a book like Perl Medic, you'll have the tools at hand to help ease the work ahead into a more manageable task. And you'll make it easier for "the next guy".

You can purchase Perl Medic: Transforming Legacy Code from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.

Comments

Dupe?

[Willis Wasabi]

What now? Duplicate book reviews?

Pamela Jones EXPOSED

[Anonymous Coward]

Who Is Pamela Jones?
By Maureen O'Gara

Friday May 6, 2005 - A few weeks ago I went looking for the elusive harridan who supposedly writes the Groklaw blog about the SCO v IBM suit.

The now-famous opinion-shaping open source leader Pamela Jones, aka PJ, doesn't give conventional face-to-face interviews. Never has, near as anyone knows. All communication is virtual. Only one person in the world has ever claimed to have met her - in the pressroom at LinuxWorld in Boston complete with a Pamela Jones badge - and described her as a fortyish reddish-blonde who giggled a lot.

Oh yeah? Wonder what cold crème she uses.

Pamela Jones is a 61-year-old Jehovah's Witness who lives in a shabby genteel garden apartment in desperate need of an interior decorator on a heavily trafficked commercial road at 304 North Central Avenue in Hartsdale, New York. Hartsdale is in Westchester and Westchester is IBM territory.

See, even though Groklaw treats cell phones like they were Kleenex and changes its unpublished numbers regularly, one number it left with a journalist led to this flat and - wouldn't you know it but - some calls from there had been placed to the courts in Utah and to the Canopy Group so obviously this just isn't any Pamela Jones.

Pamela has lived in apartment 1A for 10 years at least, according to the super, who says he's watched people move in, have children, and the children marry and move away.

Now, this isn't your usual anonymous New York apartment. It's practically a self-contained village where the super goes for the old ladies' groceries when there's snow on the ground and people know each other's business.

But the super didn't know much about Pamela except that she had a computer, worked at home (maybe sometimes) for a lawyer, was "paranoid" - his word - and "sensitive to smells."

He remembered how he was cleaning paintbrushes one day and she came running down the stairs screaming "Fire."

She was also missing and had been for weeks.

Nobody there knew where she was.

She had up and disappeared one day, and the super was worried about her. He said her son had dropped by and he didn't know where she was, and that some strange man that "nobody knew," as the super described him, had tried to get into her apartment while she was gone - the Medeco lock she had had installed on her door - something nobody else in the complex seemed to feel a need for - was more expensive than the door. But, as it happened, the super said, she had just sent in her rent in an envelope postmarked Connecticut.

Like an episode out of "Where in the World is Carmen San Diego," the trail led to 10 Bittersweet Trail in Norwalk, Connecticut, 24 miles away. Sure enough, parked in the driveway was Pamela's car, just as the super had described it, a dark gray '90s Japanese number with a bunch of Jehovah Witness pamphlets tossed on the backseat.

The woman at the house, Barbara Sharnik, told a disjointed story. She didn't know Pamela, Pamela hated her, Pamela wasn't there, Pamela left her car there because it got bumped, Pamela left her car there because she left town, and so on.

Afterwards Barbara called the cops, and then the cops called the number we left with her and the cops said that she was Pamela's mother and that Pamela was on the run and had shacked up with her mother because she had gotten "threatening mail" weeks before and that she had just gotten spooked again because "people were getting hurt around [my] stories" and had lighted out for Canada.

Odd, the subject of my stories - or any stories - never came up during our brief interview. I was just looking for Pamela.

That left Pamela's son, Nicolas Richards, who, as it happens, had been in the software business in Manhattan until - why, my goodness - things seem to have come a cropper right around the time Groklaw came into existence.

Nick and his ma were apparently involved together in Medabiliti Inc, an ISV, because one Pamela Jones with a Westche

What dupe?

[kclittle]

What has /. come to? Preemtive "dupe flames"? :D