Customer Reviews

Perl Debugged

5 star:		(8)
4 star:		(2)
3 star:		(0)
2 star:		(0)
1 star:		(0)

 

 

I'm tremendously pleased with Perl Debugged. It's half a book about Perl debugging, and half a book with more general advice, all pleasantly blended together. Peter and Ed take you on an unrivaled tour of the ups and downs of Perl debugging. It's sort of like Effective Perl Programming's "Debugging" chapter except hugely and brilliantly expanded. It's comprehensive and imaginative without being pedantic. It covers the Perl debugger (of course), it covers the different types of errors you'll encounter in Perl programs, it covers debugging strategies, and (very important) it covers the always-icky topic of debugging CGI programs. And some other topics ....

Even experienced Perl programmers will enjoy reading this book. You may think you've seen it all but I guarantee you that you haven't seen all of the examples of weirdness featured herein. It reminds me of Kon and Bal's debugging "brainteasers" in Apple's now defunct Develop magazine.

I *highly* recommend Perl Debugged to anyone at the beginning or intermediate stage in Perl programming, particularly to programmers who have less than 2-4 years of debugging experience in general. An experienced programmer, on the other hand, will want to buy a copy (copies?) to browse and then hand to his junior co-worker(s) with stern instructions to "read first, code later." (Reminds me of the time I bought Bugs in Writing.)

Apparently the authors have a way with words. The prose is unusually good--not just by the standards of technical books--colorful, extremely clear, and enjoyable to read. (The illustrations by Peter's sister-in-law are great.) About the only thing that "bugs" me is the authors' use of "semantical" in preference to "semantic."

This book is a must for perl programmers. Throughout the book, the authors develop 46 "Perls of Wisdom". These guidelines will help you write code with fewer bugs and help you fix bugs when they do come up - and they will! I tend to enjoy software books with a little humor to them, and this one fits the bill. Here are the highlights from the book:

Ch. 1-

Gives some background on the perl language and good tips on accessing the documentation for various parts of perl on various platforms.

Ch. 2-

Kind of a touchy/feely chapter; however, there is wisdom in it. It helps you understand how your attitudes, beliefs, and behaviors affect your code. Don't skip it.

Ch. 3-

This chapter gives you some good advice on how to avoid bugs in your program. One of these is documentation. I've found that documenting something makes you think about things you otherwise might not have.

Ch. 4-

Gives some common sources of bugs in perl including syntax, precedence, and regular expressions.

Ch. 5-

How to get formatted printouts of variables in your using Data::Dumper. This is a step up from print statements, and is easy to use.

Ch. 6-

Includes good information on testing your code and the perl modules available to assit you in test harnesses and coverage tests.

Ch. 7-

This is the gem of the book. It is a step by step guide to using the perl debugger. If reading man pages makes your head hurt, you will find this tutorial much more user friendly.

Ch. 8-

An excellent chapter on interpreting the syntax error reports that perl spits out.

Ch. 9-

The runtime exception counterpart to the previous chapter. It contains a discussion of perl exception handling vs. that of java or c++.

Ch. 10-

This chapter deals with the tough topic of code that compiles and runs, but gives the wrong answer. It gives techinques for seeing how perl interpreted your code.

Ch. 11-

This chapter gives you advice for improving performance using the Benchmark module.

Ch. 12-

A nice comparison to other languages. If you are fluent in another programming language, it is helpful to know how the it compares to perl.

The examples in this book are what make it the most useful. They show you how to use various perl modules to make your code better. Being new to the language, I wasn't even aware that some of these modules existed. Unless you are a perl master already, you should find plenty of useful information in Perl Debugged.

The ideal reader of this book would be someone who's been exposed to most of Perl and knows about packages, modules and references (the Llama/Alpaca combo, for instance), but who isn't necessarily experienced with other languages. If you are that sort of person, this should be close to the top of your Perl reading list.

There's an abundance of good material to be found here -- yes, there's an entire chapter on working the Perl debugger, but don't let the book's title fool you, it's not just about debugging. There's also advice on code style and layout, common idioms and features of Perl such as the behaviour of $_, autovivification, local, and optional parentheses.

Additionally, there are introductions to logging (in the context of debug flags), unit testing, code coverage, and error handling. Rounding off the book are chapters on benchmarking, profiling and some simple optimisation techniques (e.g. don't shell out to an external program if you can do the task in perl, use pipes and fork instead of writing to a temporary file), a chapter of tips for programmers coming to Perl from Java, shell scripting, C, C++ and Fortran. Finally there's a chapter covering debugging CGI programs.

Throughout, there's also some more philosophical (or touchy-feely) material, with exhortations to being a good citizen of the Republic of Perl and your work environment. If you're a more experienced developer, and you've read the likes of Code Complete and Refactoring, much of this is either obvious or has been given in more detail in other books, which is why I think the less experienced you are, the more you'll get out of it.

If you've been around the block a couple of times, I think you'll find that while there is a lot of ground covered, it's not particular deep. It's good to have issues like unit testing, profiling, benchmarking and logging introduced, but you'll quickly have to look elsewhere for more detailed (not to mention up-to-date) information for use in your own code. If you've read the likes of Effective Perl Programming, Perl Testing and of course, the mighty Perl Best Practices, there's not a lot left to see. However, chapter 8 presents some neat puzzlers, where a seemingly innocuous piece of code is suffering from a missing, misplaced or transposed character, and some useful tips for interpreting the syntax errors are presented.

Overall, this is nicely written in an unfussy, friendly style which assumes the reader is not a complete beginner. Ungrizzled non-veterans of Perl should consider this well worth taking a look at, especially as a companion to Perl Medic.

This is one of the best practical guides to Perl debugging, or debugging in general, that I've found. Instead of a laundry list of debugging features and options the author provides a set of practical techniques for tackling real world Perl debugging problems. While much of this will be old hat to those who spend a lot of time immersed in debugging, this book is a great resource for the new or occasional programmer.

This was a surprise gem for me. I had been looking at several Perl books that covered debugging. I already have a couple of good references for the Perl debugger; what I wanted was a book that was more about "how" to debug...strategies, techniques, etc. The other books on debugging Perl was I looked at appeared to be more comprehensive but I didn't want to have to read any really long books. I decided to try this one which seemed to cover the topics I was looking for and was a tractable book in terms of length. I was really surprised at just how superb this book is. It did cover the topics I thought and hoped it would; but the writing style was surprising and terrific for me.

I am what the authors occasionally describe as a diehard C/C++/Java programmer and have taught this style of language for over 20 years. My experience with Perl is enough to be able to program at the reasonable level and I taught a course in programming with Perl several years ago.
To the programmer accustomed to the syntax of C-like languages, the structure and idioms of Perl can be difficult to understand. Using it well is similar to learning a second spoken language, where phrases that are superficially imprecise, such as "take a hike", can be difficult to translate.
Once you learn the language, the next and most significant step is to learn to test the code so that errors are reduced and hopefully eliminated. This is the step where knowledge of the idioms is most critical, because before you can successfully debug, you must understand.
That is the level at which this book is written, if you pick it up and are not familiar with Perl, then it will do you little to no good. However, if you do know the language well enough to program in it, then the tactics described here will be very helpful in your goal of creating a functional and error-free Perl program. While that statement is more applicable to the programmers that have come to Perl from other languages, even veterans of the Perl programming wars will find points of value.

Finally, a book not only on how to use the debugger, but when and why to use the debugger. Great quick read that will add another level to your perl programming that is uncommonly used, but incredibly powerful.

Fun book, of 3 perl metabooks (others Hall/Schwartz Efficient Perl (everybody shd read) and Brown's Debugging Perl (I haven't read much) ). There's "35 best hackers", good bibliographies/TOC index could be more detailed) and the 1st 100 pages had me thinking authors were watching my perl screwups over my shoulder. One wish list item: more info on vim, gnu/xemacs (getting syntax coloring/tabbing right on NT, compiling .els)

$1MM Question: can these books keep perl growing? Python,ruby don't seem to need these debugging/dev practices books.

Another question: can any books on perl/python stay up to date? Since this came out: komodo (you are trying to get your boss to pay $250 subscription, aren't you?), Visual perl/python, python DBI, 3 or 4 more Oreillys, etc. etc.

Fun book, of 3 perl metabooks (others Hall/Schwartz Efficient Perl (everybody shd read) and Brown's Debugging Perl (I haven't read much) ). There's "35 best hackers", good bibliographies/TOC index could be more detailed) and the 1st 100 pages had me thinking authors were watching my perl screwups over my shoulder. One wish list item: more info on vim, gnu/xemacs (getting syntax coloring/tabbing right on NT, compiling .els)

$1MM Question: can these books keep perl growing? Python,ruby don't seem to need these debugging/dev practices books.

Another question: can any books on perl/python stay up to date? Since this came out: komodo (you are trying to get your boss to pay... subscription, aren't you?), Visual perl/python, python DBI, 3 or 4 more Oreillys, etc. etc.

Fun book, of 3 perl metabooks (others Hall/Schwartz Efficient Perl (everybody shd read) and Brown's Debugging Perl (I haven't read much) ). There's "35 best hackers", good bibliographies/TOC index could be more detailed) and the 1st 100 pages had me thinking authors were watching my perl screwups over my shoulder. One wish list item: more info on vim, gnu/xemacs (getting syntax coloring/tabbing right on NT, compiling .els)

$1MM Question: can these books keep perl growing? Python,ruby don't seem to need these debugging/dev practices books.

Another question: can any books on perl/python stay up to date? Since this came out: komodo (you are trying to get your boss to pay $250 subscription, aren't you?), Visual perl/python, python DBI, 3 or 4 more Oreillys, etc. etc.