@@ -2,32 +2,130 @@ Z<cpan> -Explaining the CPAN -Explaining how to use it? - -Where do I cover features of Perl that make it useful without explaining them? - -Modularity: - - packages - - modules - - objects - -Community standards: - - installability - - testing - - documentation standards - - CPAN accoutrements: - - CPAN testers - - RT accounts - - ratings - - history and documentation - - dependencies - - rough standards on licensing - -Usability: - - nearly configuration-free running - - CPAN client included in core - - strong core culture of use and recommendation - -Broad applicability: +If you have a problem, chances are someone's already started to solve it and +uploaded code to the CPAN. Perl 5 is a pragmatic language. It'll help you get +your work done. Yet the ever-pragmatic Perl community has extended that +language and made their work available to the world. + +The line between a modern language and its libraries is thin and fuzzy. Is a +language only syntax? Is it the core libraries? Is it the availability of +external libraries and the ease at which you can use them within your own +projects? + +X<CPAN> + +Regardless of how you answer those questions for any other language, modern +Perl programming makes heavy use of the CPAN (U<http://www.cpan.org/>). The +CPAN, or Comprehensive Perl Archive Network, is an uploading and mirroring +system for redistributable, reusable Perl code. It's one of -- if not I<the> +largest -- archives of libraries of code in the world. + +=begin notetip + +In the four months between the outline and first draft of this chapter, the +CPAN I<added> 500 registered uploaders and 7215 indexed modules in 1561 +distributions. + - 7258 uploaders/66400 modules/17268 distributions + - 7758 uploaders/73615 modules/18829 distributions + +=end notetip + +Several features make the CPAN powerful: almost all of them community +conventions that have grown up around the system. Remember, at its heart it's +merely a distribution service. When it works for you -- and it often does -- +that's due to the hard work of thousands of volunteers. + +X<distribution> +X<module> + +CPAN mirrors I<distributions>, which tend to be collections of reusable Perl +code. A single distribution can contain one or more I<module>, which is a +self-contained library of Perl code. Each distribution lives in its own +namespace on the CPAN, contains its own metadata, and is buildable, +installable, updateable, and testable on its own. + +X<search.cpan.org> + +Many problems you're likely to encounter have stable and available CPAN +distributions available for your use, modification, and redistribution. The +U<http://search.cpan.org/> website is often an effective way to browse +available distributions. + +=for author + +I don't like the tone of the following paragraph. The rhetorical device grates. + +=end for + +If CPAN is merely a mirroring service, how do you know that any random CPAN +distribution is usable and useful? As mentioned earlier, the community +standards which have grown up around the CPAN tend to improve the quality and +utility of code. In particular, CPAN distributions have: + +=over 4 + +=item Standards for installation to work with automated CPAN installers. + +=item Standards for metadata to describe what each distribution includes and any dependencies of the distribution. + +=item Standards for documentation and licensing to describe what the +distribution does and how you may use it. + +=back + +Several additional services build in the CPAN to provide comprehensive +automated testing and reporting of every CPAN distribution for adherence to +packaging and distribution guidelines and correctness of behavior on various +platforms and versions of Perl. Every CPAN distribution has its own ticket +queue on U<http://rt.cpan.org/> for reporting bugs and working with authors. +Distributions also have historical versions available on the CPAN, ratings, +annotations for the documentation, and other useful information. All of this +is available from search.cpan.org. + +X<CPAN.pm> +X<CPANPLUS> + +Modern Perl installations include two clients to connect to, search, download, +build, test, and install CPAN distributions, CPAN and CPANPLUS. They behave +equivalently; their use is a matter of taste. This book recommends the use of +CPAN solely due to its ubiquity. + +CPAN configuration is largely decision-free. For any complete installation of +Perl, you may start the client with: + + $ B<cpan> + +To install a distribution: + + $ B<cpan Modern::Perl> + +=for author + +Need fact-checking; what's the new configuration system? + +=end for + +=begin notetip + +Even though the CPAN client is a core module for the Perl 5 distribution, you +may also have to install standard development tools such as a C<make> utility +and possibly a C compiler to install all of the distributions you want. +Strawberry and Chocolate Perl include such utilities for Windows users. Mac OS +X users need their developer tools installed; Unix and Unix-like users, consult +your local system administrator. + +=end notetip + +For all of this configuration, you gain access to over 73,000 individual Perl +modules in almost 19,000 distributions. These modules cover everything from +database access to profiling tools to protocols for almost every network device +ever created to sound and graphics libraries and wrappers for shared libraries +on your system. + +=for author + +Where's that link to the CPAN guide? How about a section about local::lib +here? + +=end for sections/cpan.pod a2286fee9c3c70735d0ce629a077078cf7db789b chromatic chromatic@wgz.org http://github.com/chromatic/modern_perl_book/commit/74c2ca634eb7924ecaff7ef042b47ed5699a571e 74c2ca634eb7924ecaff7ef042b47ed5699a571e

2009-10-19T19:38:55-07:00

Filled out CPAN section. It needs more work, but it's much better. 0d2ccad4fefb39622f7bd1e50b81438530a517da chromatic chromatic@wgz.org