Learning Perl, Fourth Edition

Chapter 15. Perl Modules

There is a lot more to Perl than what we’re able to show you in this book, and there are a lot of people doing a lot of interesting things with Perl. If there is a problem to solve, then somebody has probably already solved it and made their solution available on the Comprehensive Perl Archive Network (CPAN), which is a worldwide collection of servers and mirrors containing thousands of modules of reusable Perl code.

If you want to learn how to write modules, consult the Alpaca book. In this chapter, we’ll show you how to use modules that already exist.

Finding Modules

Modules come in two types: those that come with Perl and those that you can get from CPAN to install yourself. Unless we say otherwise, the modules we discuss come with Perl.

To find modules that don’t come with Perl, start at CPAN Search, http://search.cpan.org, or Kobes’ Search, http://kobesearch.cpan.org.^[337] You can browse through the categories or search directly.

Either of those resources are great since you can read the module documentation before you download the entire package. You can also browse the distribution and have a peek at the files without bothering to install the modules.

Before you go looking for a module, check if it has been installed already. One way is to just try to read the documentation with perldoc. The CGI.pm module comes with Perl (and we’ll discuss it later in this chapter), so you should be able to read its documentation.

    $ perldoc CGI

Try it with a module that ...