parent

Section: Perl Programmers Reference Guide (3perl)
Updated: 2019-04-20
Page Index

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', 'Bar';

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" 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';

HISTORY

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

CAVEATS

AUTHORS AND CONTRIBUTORS

Rafae.l Garcia-Suarez, Bart Lateur, Max Maischein, Anno Siegel, Michael Schwern

MAINTAINER

Max Maischein " corion@cpan.org "

LICENSE

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