


parent(3p)       Perl Programmers Reference Guide      parent(3p)


NAME
       parent - Establish an ISA relationship with base classes
       at compile time

SYNOPSIS
           package Baz;
           use parent qw(Foo Bar);

DESCRIPTION
       Allows you to both load one or more modules, while setting
       up inheritance from those modules at the same time.
       Mostly similar in effect to

           package Baz;
           BEGIN {
               require Foo;
               require Bar;
               push @ISA, qw(Foo Bar);
           }

       By default, every base class needs to live in a file of
       its own.  If you want to have a subclass and its parent
       class in the same file, you can tell "parent" not to load
       any modules by using the "-norequire" switch:

         package Foo;
         sub exclaim { "I CAN HAS PERL" }

         package DoesNotLoadFooBar;
         use parent -norequire, 'Foo', 'Bar';
         # will not go looking for Foo.pm or Bar.pm

       This is equivalent to the following code:

         package Foo;
         sub exclaim { "I CAN HAS PERL" }

         package DoesNotLoadFooBar;
         push @DoesNotLoadFooBar::ISA, 'Foo';

       This is also helpful for the case where a package lives
       within a differently named file:

         package MyHash;
         use Tie::Hash;
         use parent -norequire, 'Tie::StdHash';

       This is equivalent to the following code:

         package MyHash;
         require Tie::Hash;
         push @ISA, 'Tie::StdHash';

       If you want to load a subclass from a file that "require"



perl v5.10.1                2009-10-12                          1





parent(3p)       Perl Programmers Reference Guide      parent(3p)


       would not consider an eligible filename (that is, it does
       not end in either ".pm" or ".pmc"), use the following
       code:

         package MySecondPlugin;
         require './plugins/custom.plugin'; # contains Plugin::Custom
         use parent -norequire, 'Plugin::Custom';

DIAGNOSTICS
       Class 'Foo' tried to inherit from itself
           Attempting to inherit from yourself generates a
           warning.

               use Foo;
               use parent 'Foo';

HISTORY
       This module was forked from base to remove the cruft that
       had accumulated in it.

CAVEATS
SEE ALSO
       base

AUTHORS AND CONTRIBUTORS
       Rafaeel Garcia-Suarez, Bart Lateur, Max Maischein, Anno
       Siegel, Michael Schwern

MAINTAINER
       Max Maischein " corion@cpan.org "

       Copyright (c) 2007 Max Maischein "<corion@cpan.org>" Based
       on the idea of "base.pm", which was introduced with Perl
       5.004_04.

LICENSE
       This module is released under the same terms as Perl
       itself.



















perl v5.10.1                2009-10-12                          2


