NAME¶

Perl::Critic::Policy::ValuesAndExpressions::ProhibitLongChainsOfMethodCalls - Long chains of method calls indicate tightly coupled code.

AFFILIATION¶

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

DESCRIPTION¶

A long chain of method calls usually indicates that the code knows too much about the interrelationships between objects. If the code is able to directly navigate far down a network of objects, then when the network changes structure in the future, the code will need to be modified to deal with the change. The code is too tightly coupled and is brittle.

    $x = $y->a;           #ok
    $x = $y->a->b;        #ok
    $x = $y->a->b->c;     #questionable, but allowed by default
    $x = $y->a->b->c->d;  #not ok

CONFIGURATION¶

This policy has one option: "max_chain_length" which controls how far the code is allowed to navigate. The default value is 3.

TO DO¶

Add a "class_method_exemptions" option to allow for things like

    File::Find::Rule
        ->name('*.blah')
        ->not_name('thingy')
        ->readable()
        ->directory()
        ->in(@roots);

AUTHOR¶

Elliot Shank "<perl@galumph.com>"

COPYRIGHT¶

Copyright (c) 2007-2009 Elliot Shank. 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.