From: Dave Rolsky <autarch@urth.org>
Date: Mon, 20 Feb 2012 22:26:59 +0000 (-0600)
Subject: Add one more deleted recipe to the Legacy section
X-Git-Tag: 2.0500~42
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=cb235596bb95c6d502e671c85f525aa9ae50e4c0;p=gitmo%2FMoose.git

Add one more deleted recipe to the Legacy section
---

diff --git a/lib/Moose/Cookbook.pod b/lib/Moose/Cookbook.pod
index 2b1e6a9..8e96f71 100644
--- a/lib/Moose/Cookbook.pod
+++ b/lib/Moose/Cookbook.pod
@@ -213,6 +213,8 @@ them in case in you encounter these usages in the wild.
 
 =item L<Moose::Cookbook::Legacy::Table_ClassMetaclass>
 
+=item L<Moose::Cookbook::Legacy::Debugging_BaseClassReplacement>
+
 =back
 
 =head1 SEE ALSO
diff --git a/lib/Moose/Cookbook/Legacy/Debugging_BaseClassReplacement.pm b/lib/Moose/Cookbook/Legacy/Debugging_BaseClassReplacement.pm
new file mode 100644
index 0000000..de4d4da
--- /dev/null
+++ b/lib/Moose/Cookbook/Legacy/Debugging_BaseClassReplacement.pm
@@ -0,0 +1,134 @@
+package Moose::Cookbook::Legacy::Debugging_BaseClassReplacement;
+
+# ABSTRACT: Providing an alternate base object class
+
+
+
+=pod
+
+=head1 NAME
+
+Moose::Cookbook::Extending::Recipe3 - Providing an alternate base object class
+
+=head1 VERSION
+
+version 2.0402
+
+=head1 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' );
+  }
+
+=head1 DESCRIPTION
+
+B<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 C<MyApp::Base> and add C<S<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 C<MyApp::Base> for you.
+
+Then, instead of writing C<S<use Moose>> you can write C<S<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 L<Moose::Exporter>. When we call C<<
+Moose::Exporter->setup_import_methods( also => 'Moose' ) >> it builds
+C<import> and C<unimport> methods for you. The C<< also => 'Moose' >>
+bit says that we want to export everything that Moose does.
+
+The C<import> method that gets created will call our C<init_meta>
+method, passing it C<< for_caller => $caller >> as its
+arguments. The C<$caller> is set to the class that actually imported
+us in the first place.
+
+See the L<Moose::Exporter> docs for more details on its API.
+
+=for testing-SETUP use Test::Requires {
+    'Test::Output' => '0',
+};
+
+=head1 USING MyApp::UseMyBase
+
+To actually use our new base class, we simply use C<MyApp::UseMyBase>
+I<instead> of C<Moose>. We get all the Moose sugar plus our new base
+class.
+
+  package Foo;
+
+  use MyApp::UseMyBase;
+
+  has 'size' => ( is => 'rw' );
+
+  no MyApp::UseMyBase;
+
+=head1 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.
+
+=begin testing
+
+{
+    package Foo;
+
+    MyApp::UseMyBase->import;
+
+    has( 'size' => ( is => 'rw' ) );
+}
+
+ok( Foo->isa('MyApp::Base'), 'Foo isa MyApp::Base' );
+
+ok( Foo->can('size'), 'Foo has a size method' );
+
+my $foo;
+stderr_like(
+    sub { $foo = Foo->new( size => 2 ) },
+    qr/^Making a new Foo/,
+    'got expected warning when calling Foo->new'
+);
+
+is( $foo->size(), 2, '$foo->size is 2' );
+
+=end testing
+
+=head1 AUTHOR
+
+Moose is maintained by the Moose Cabal, along with the help of many contributors. See L<Moose/CABAL> and L<Moose/CONTRIBUTORS> for details.
+
+=head1 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.
+
+=cut
+
+
+__END__
+