Perl::Critic::Policy::Bangs::ProhibitRefProtoOrProto(3)

NAME
Perl::Critic::Policy::Bangs::ProhibitRefProtoOrProto - Create a clone() method if you need copies of objects.

AFFILIATION
This Policy is part of the Perl::Critic::Bangs distribution.

DESCRIPTION
Many times you'll see code for object constructors that's been cut-and-pasted from somewhere else, and it looks like this:

    sub new {
        my $proto = shift;
        my $class = ref($proto) || $proto;
        my $self  = bless {}, $class;
        ...
    }

The $class is derived from the first parameter, whether it's the class name, or an existing object. This lets you do this:

    my $fido = Dog->new();

which is very common, and the less likely

    my $rover = $fido->new();

Now, why would you want to instantiate an object based on the type of another object? If you want to make $rover a clone of $fido, then Dog should have a clone() method, instead of overloading the meaning of new().

That's all the "ref($proto) || $proto" does for you. If you don't need that dubious functionality, then write your constructors like this:

    sub new {
        my $class = shift;
        my $self = bless {}, $class;
    }

See also Randal Schwartz's take on it at <http://www.stonehenge.com/merlyn/UnixReview/col52.html>.

CONFIGURATION
This Policy is not configurable except for the standard options.

AUTHOR
Andrew Moore <amoore@mooresystems.com>

ACKNOWLEDGMENTS
Adapted from policies by Jeffrey Ryan Thalhammer <thaljef@cpan.org>, and work done by Andrew Moore <amoore@mooresystems.com>.

COPYRIGHT
Copyright (C) 2006-2013 Andy Lester

This library is free software; you can redistribute it and/or modify it under the terms of the Artistic License 2.0.