Perl::Critic::Policy::ControlStructures::ProhibitDeepNests - Don't write deeply nested loops and conditionals.


This Policy is part of the core Perl::Critic distribution.


Deeply nested code is often hard to understand and may be a sign that it needs to be refactored. There are several good books on how to refactor code. I like Martin Fowler's "Refactoring: Improving The Design of Existing Code".


The maximum number of nested control structures can be configured via a value for max_nests in a .perlcriticrc file. Each for-loop, if-else, while, and until block is counted as one nest. Postfix forms of these constructs are not counted. The default maximum is 5. Customization in a .perlcriticrc file looks like this:

    max_nests = 3


Jeffrey Ryan Thalhammer <>


Copyright (c) 2005-2011 Imaginative Software Systems. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license can be found in the LICENSE file included with this module.