Item Description: Perl for "Accidental Programmers"
Review Synopsis: A great introduction to Perl for people who aren't programmers by training
First things first. This isn't the book that I thought it was going to be. I was expecting to read a book that taught experienced programmers some Perl tricks that made it easier to manage a web site - something like a companion piece to O'Reilly's Perl for System Administration by David Blank-Edelman. Turns out that's not what this book is at all.
Instead, it's an introduction to Perl for someone who runs a web site and decides that they need to take their computer knowledge to the next level and learn some programming skills. Callender calls these people "accidental programmers" and he is very understanding of their needs having been one himself only a few years ago.
So immediately this book has a completely different target audience to the majority of O'Reilly's Perl books. It's competing against all the brightly coloured books with titles like Perl for Morons or Learn Perl in 30 Seconds. These books are, almost without exception, written by people with minimal Perl knowledge, so it should come as no surprise that Callender's book is vastly superior to all of them.
The first major advantage that this book has is that it doesn't simply try to sell Perl as "the CGI language". Callender is at pains to point out that Perl can be useful for any number of other tasks involved in running a web site. Very early on we are looking at updating the links in an HTML file using regular expressions (and there's even a discussion on the fragility of this approach and pointers to better solutions using CPAN modules). A little later on we are looking at writing reports on web site hits by parsing the access logs. This is the kind of work that Perl excels at - the fact that you can you use the same language to write CGI programs as well should be seen as a bonus.
As I mentioned before, Callender is not a programmer by training (this is sometimes obvious from his code examples) but he has obviously learned from good sources. He encourages all the good habits that are missing from most of his competitors books - all of his examples use -w and use strict and all of CGI programs are written using CGI.pm. There's even a far more detailed explaination of the importance of security and taint mode than I've seen in any book aimed at this audience. Another bonus is the discussion of the necessity and mechanics of file locking.
Another topic that often missing from beginners books is the huge library of ready-written Perl modules called the CPAN. Many authors seem to think that this concept is beyond their audience and thereby many newcomers to Perl never discover this treasure chest and spend their entire programming life studiously reinventing wheels unnecessarily. Callender has no time for this point of view and in the middle of chapter 11 he has us downloading and installing modules from CPAN. This approach is bound to lead to more productive Perl programmers.
I mentioned that Callender was himself an accidental programmer. This means that the chapters are full of anecdotes of the kind of problems he experienced when first starting to program in Perl. As well as learning about programming in general, Perl and CGI, most of the book's target audience will be Windows or Mac users who have no knowledge of Unix and, in most cases, that's the operating system that their web server will be running on. Once again, Callender has already made this journey and he proves to be a most able guide.
So, all in all, I think this is a great book. If you're thinking that you need to learn some Perl in order to add CGI programs to your web site, then please consider this book before any of the other beginners Perl and CGI books. You'll end up with a much better understanding after reading this book. But this leads me to my only problem with the book. I'm really not convinced that the people who are in the target audience will pick up this book when they are browsing in a bookstore. I think that O'Reilly books are seen as being for experts and I also think that the title doesn't explain the contents of the book very well.
I could, of course, be wrong. I hope I am.