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Manual Reference Pages  -  PERL::CRITIC::POLICY::BANGS::PROHIBITREFPROTOORPROTO (3)

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NAME

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

CONTENTS

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) 2006-2011 Andy Lester

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

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perl v5.20.3 PERL::CRITIC::POLICY::BANGS::PROHIBITREFPROTOORPROTO (3) 2011-06-20

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