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Moose::Cookbook::Legacy::Debugging_BaseClassReplacement(3)oDocumentationy::Debugging_BaseClassReplacement(3)



NAME
       Moose::Cookbook::Legacy::Debugging_BaseClassReplacement - Providing an alternate base object class

VERSION
       version 2.0604

SYNOPSIS
         package MyApp::Base;
         use Moose;

         extends 'Moose::Object';

         before 'new' => sub { warn "Making a new " . $_[0] };

         no Moose;

         package MyApp::UseMyBase;
         use Moose ();
         use Moose::Exporter;

         Moose::Exporter->setup_import_methods( also => 'Moose' );

         sub init_meta {
             shift;
             return Moose->init_meta( @_, base_class => 'MyApp::Base' );
         }

DESCRIPTION
       WARNING: Replacing the base class entirely, as opposed to applying roles to the base class, is
       strongly discouraged. This recipe is provided solely for reference when encountering older code that
       does this.

       A common extension is to provide an alternate base class. One way to do that is to make a
       "MyApp::Base" and add "extends 'MyApp::Base'" to every class in your application. That's pretty
       tedious. Instead, you can create a Moose-alike module that sets the base object class to
       "MyApp::Base" for you.

       Then, instead of writing "use Moose" you can write "use MyApp::UseMyBase".

       In this particular example, our base class issues some debugging output every time a new object is
       created, but you can think of some more interesting things to do with your own base class.

       This uses the magic of Moose::Exporter. When we call "Moose::Exporter->setup_import_methods( also =>
       'Moose' )" it builds "import" and "unimport" methods for you. The "also => 'Moose'" bit says that we
       want to export everything that Moose does.

       The "import" method that gets created will call our "init_meta" method, passing it "for_caller =>
       $caller" as its arguments. The $caller is set to the class that actually imported us in the first
       place.

       See the Moose::Exporter docs for more details on its API.

NAME
       Moose::Cookbook::Extending::Recipe3 - Providing an alternate base object class

VERSION
       version 2.0402

USING MyApp::UseMyBase
       To actually use our new base class, we simply use "MyApp::UseMyBase" instead of "Moose". We get all
       the Moose sugar plus our new base class.

         package Foo;

         use MyApp::UseMyBase;

         has 'size' => ( is => 'rw' );

         no MyApp::UseMyBase;

CONCLUSION
       This is an awful lot of magic for a simple base class. You will often want to combine a metaclass
       trait with a base class extension, and that's when this technique is useful.

AUTHOR
       Moose is maintained by the Moose Cabal, along with the help of many contributors. See "CABAL" in
       Moose and "CONTRIBUTORS" in Moose for details.

COPYRIGHT AND LICENSE
       This software is copyright (c) 2012 by Infinity Interactive, Inc..

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
       programming language system itself.

AUTHOR
       Moose is maintained by the Moose Cabal, along with the help of many contributors. See "CABAL" in
       Moose and "CONTRIBUTORS" in Moose for details.

COPYRIGHT AND LICENSE
       This software is copyright (c) 2012 by Infinity Interactive, Inc..

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
       programming language system itself.



perl v5.16.2                                     2012-09-19okbook::Legacy::Debugging_BaseClassReplacement(3)