A Myriad of Modules (Perl and XML)

1.4. A Myriad of Modules

One of Perl's strengths is that it's a community-driven language. When Perl programmers identify a need and write a module to handle it, they are encouraged to distribute it to the world at large via CPAN. The advantage of this is that if there's something you want to do in Perl and there's a possibility that someone else wanted to do it previously, a Perl module is probably already available on CPAN.

However, for a technology that's as young, popular, and creatively interpretable as XML, the community-driven model has a downside. When XML first caught on, many different Perl modules written by different programmers appeared on CPAN, seemingly all at once. Without a governing body, they all coexisted in inconsistent glee, with a variety of structures, interfaces, and goals.

Don't despair, though. In the time since the mist-enshrouded elder days of 1998, a movement towards some semblance of organization and standards has emerged from the Perl/XML community (which primarily manifests on ActiveState's perl-xml mailing list, as mentioned in the preface). The community built on these first modules to make tools that followed the same rules that other parts of the XML world were settling on, such as the SAX and DOM parsing standards, and implemented XML-related technologies such as XPath. Later, the field of basic, low-level parsers started to widen. Recently, some very interesting systems have emerged (such as XML::SAX) that bring truly Perlish levels of DWIMminess out of these same standards.[2]

[2]DWIM = "Do What I Mean," one of the fundamental philosophies governing Perl.

Of course, the goofy, quick-and-dirty tools are still there if you want to use them, and XML::Simple is among them. We will try to help you understand when to reach for the standards-using tools and when it's OK to just grab your XML and run giggling through the daffodils.