/ 
Perl-Critic-Bangs-0.22
River stage two • 8 direct dependents • 13 total dependents
/ Perl::Critic::Policy::Bangs::ProhibitRefProtoOrProto

NAME

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

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

AUTHOR

Andrew Moore <amoore@mooresystems.com>

ACKNOWLEDGEMENTS

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

COPYRIGHT

Copyright 2006 Andy Lester <andy at petdance.com>.

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.