NAME Package::Debug - Add ENV/Config controlled debug tokens to your code VERSION version 0.1.0 SYNOPSIS There is a lot of code on "CPAN" that has something like this in it: our $DEBUG = $ENV{MY_PACKAGE_NAME_DEBUG}; or something like sub DEBUG { return if not $ENV{MY_PACKAGE_NAME_DEBUG}; } or something like: if( $ENV{MY_PACKAGE_NAME_DEBUG} ) { *DEBUG=sub{ withdebug } } else { *DEBUG=sub { noop } } These are mostly simple and straight forward, ... however, they artificially limit what you can do, at the cost of making ugly code. This module aims to implement the common utility, with less fuss: $ENV{MY_BAZ_DEBUG} = 1; package My::Baz; use Package::Debug; ... sub foo { DEBUG("message"); } And all the right things should still occur. Additionally, this module will eventually add a bunch of features, that are by default off, but can be toggled on using environment or configuration files. EXPECTED FEATURES * Deferrable debug mechanism The defacto "DEBUG()" stub when not in a debug environment should be a no-op, or as close to a no-op as possible. However, when debugging is turned on, debugging back ends should also be controllable via env/configuaration, and proxy to things like Log::Message and friends. * Per-package debug granularity Every package will get its own independent DEBUG key, and DEBUG for a class can be toggled with an %ENV key relevant to that class. * Global Debugging In addition to package level granularity, global debugging can also be enabled, while still seeing the individual packages the debug message emanates from. PERFORMANCE For the best speed, use Package::Debug; This will do its best to produce a "no-op" sub when debugging is not requested by %ENV However, this comes at a price, namely, if you want to turn on debugging in code, you have to either BEGIN { $ENV{YOUR_PACKAGE_NAME_DEBUG} = 1 } use Your::Package::Name; # debugging is on Or BEGIN { $Your::Package::Name::DEBUG = 1 } use Your::Package::Name; # debugging is on And this will not work: use Your::Package::Name; $Your::Package::Name::DEBUG = 1; # Modification of Readonly value This is because for the last example to work, the "DEBUG" sub would have to check that value every time it was called. And this will roughly double the cost of calling "DEBUG" If you want run time adjustment use Package::Debug runtime_switchable => 1; This will a - not make $DEBUG "readonly" during import. b - inject a "DEBUG" "sub" that checks the value of the former. AUTHOR Kent Fredric COPYRIGHT AND LICENSE This software is copyright (c) 2013 by Kent Fredric . This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.