Also:   “Yay!!   This is open source!   Therefore, you can see for yourself!”   :-)

Simply look-up any of those modules on http://search.cpan.org, then click on the Source hyperlink at the top of the page, next to the version-number.   Presto:   there’s the source.   Wanna know what they did and how they did it?   There are no secrets.   Wanna look at the test-suite that runs anytime the package is installed on a computer?   No secrets.

Now, you might well have stumbled-upon a package which is actually part of another package, such that “the source” actually consists of the whole package.   Well, there’s a hyperlink to that, too ... closer yet to the top of the page, next to the author’s name.

The source-code to any installed package can also be found in the library directories of your computer.   The PERL5LIB environment-variable (or its equivalent, found in some control-panel, in Windows), will tell you where.

Some libraries actually use a combination of “pure Perl” and C/C++ subroutines, in a technique called “XS.”   Nevertheless, all the relevant source-code should be right there, along with the “magick glue” that links the two together.

While you’re getting-to-know Perl, another “must have” CPAN module (family ...) to be aware of is:   Regexp::Common.   (Definitely “click next to the author’s name” on this one!   It’s big!)   A library of many hundreds of commonly-used regular expressions, all of them well-tested so that you don’t have to.

Although it is, indeed, very educational to “learn from the working examples of others,” it’s also important to “do not do a thing already done.”   CPAN-provided solutions are frequently very thorough, very complete, and very tested.   One might cautiously say that “the Perl language, itself,” is rather ordinary . . . but “the CPAN library” is one of the biggest-and-best in our industry.   “What’s all the fuss about, really?”   To me, the answer is:   CPAN.   Learn it well, use it often.

Welcome to the Monastery!