Question

I recently joined a Perl project and I need to start being productive with the codebase fairly quickly. However, I’m finding that I’m getting stuck because I don’t know where I need to change or how all the parts of the code fit together.

What are your tips and tools for becoming familiar with a Perl codebase that you have no experience with?

(Note: I realize that there’s already a similar question. I’m wondering if there’s any Perl-specific strategies.)

Answer 1

First, if the previous maintainers were doing their job well, you should have an extensive test suite and perldoc documentation for each module and script in the codebase. If so, read through the perldoc, and read through the tests. The perldoc should give you an overview of what things do, and the test suite will give you examples of the code being used in context.

Depending on the author, the internal comments may be useful in understanding the intention of the code, so looking through the actual source my provide insights into algorithms, bugs, and intended use as well.

If you don’t have any of these, proceed as you would for any badly-maintained codebase: start small, writing programs that try to use the code, and use Test::More and the like to start turning these into a test suite.

In the first case, you may find it to be very simple, in the second, very hard. Peter Scott’s Perl Medic can be very useful in assisting you in turning such a codebase into something usable and useful if you’re stuck with the second case, and Mike Thomsen’s recommendation of Effective Perl Programming is also a good one.