Perl::Critic::Policy::Bangs::ProhibitRefProtoOrProto

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 AT mooresystems DOT com>

ACKNOWLEDGMENTS

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