Introduction 

A

S

 L

ARRY

 W

ALL

, creator of Perl, puts it,  Perl makes easy jobs easy and hard jobs 

possible.  This is a large part of what makes Perl such a great language most jobs 

really are easy in Perl. But that still leaves the hard ones database access, GUI 

development, Web clients, and so on. While they are undeniably possible in pure 

Perl, they are also certainly not easy. Until you discover CPAN, that is. After that, all 

these jobs and more become a simple matter of choosing the right module. CPAN 

makes hard jobs easy. The first chapter of this book will show you how to get the 

most out of CPAN.

Although you can get a lot done just by using CPAN modules, you can go 

further by creating your own reusable Perl modules. Chapter 2 will teach you how 

to create Perl modules from the ground up. No prior module programming expe 

rience is required. Chapter 3 will improve your skills with a detailed discussion of 

module design and implementation.

Once you're a full fledged Perl module programmer, you'll naturally want to 

share your work. Chapter 4 will show you how to package your modules in module 

distributions. The next step, registering as a module author on CPAN and uploading 

your modules, is covered in Chapter 5. Chapter 6 is all about what happens after 

you upload maintaining your modules as they grow and change over time. Of 

course, some modules are better than others. Chapter 7 examines a collection of 

CPAN's most successful modules to discover the secrets of their success.

The final four chapters offer advanced training in the art of module building. 

Chapters 8, 9, and 10 teach the mysterious art of building Perl modules in C, using 

both XS and Inline::C. Chapter 11 shows you how to package whole CGI applications as 

Perl modules using CGI::Application.

What You Need to Know

To get the most out of this book, you need to know the Perl language. You don't 

need to be a Perl guru, but you should be comfortable with basic syntax. If you can 

write small programs in Perl, then you're ready to get the most out of this book.

If you're not a Perl programmer, there's still a good deal of information about CPAN 

and open source development in this book that you can use. Chapters 1, 6, and 7 

were written to be accessible to nonprogrammers. If those chapters pique your 

interest, consider reading a good introduction to the Perl language and come back 

for the rest when you're ready to write your first module.

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