Devel::Comments is a source filter for your Perl code, intended to be used
only during development. Specially-formatted 'smart' comments are replaced by
executable code to dump variables to screen or to file, display loop progress
bars, or enforce conditions. These smart comments can all be disabled at once
by commenting out the "use Devel::Comments" line, whereupon they return to
being simple, dumb comments. Your debugging code can remain in place,
guaranteed harmless, ready for the next development cycle.