From: Dave Rolsky <autarch@urth.org>
Date: Thu, 12 Feb 2009 16:49:20 +0000 (+0000)
Subject: Revised recipe 2
X-Git-Tag: 0.69~13
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=871cda31abd5e6d7af65c9d84e0bfbd5822d00e9;p=gitmo%2FMoose.git

Revised recipe 2
---

diff --git a/lib/Moose/Cookbook/Extending/Recipe2.pod b/lib/Moose/Cookbook/Extending/Recipe2.pod
index 62bd71b..85bc5d9 100644
--- a/lib/Moose/Cookbook/Extending/Recipe2.pod
+++ b/lib/Moose/Cookbook/Extending/Recipe2.pod
@@ -17,7 +17,7 @@ Moose::Cookbook::Extending::Recipe2 - Providing a role for the base object class
   use Moose::Util::MetaRole;
   use MooseX::Debugging::Role::Object;
 
-  Moose::Exporter->setup_import_methods();
+  Moose::Exporter->setup_import_methods;
 
   sub init_meta {
       shift;
@@ -53,6 +53,29 @@ L<Moose::Util::MetaRole>, we ensure that when a module does "S<use
 MooseX::Debugging>", it automatically gets the debugging role applied
 to its base object class.
 
+There are a few pieces of code worth looking at more closely.
+
+  Moose::Exporter->setup_import_methods;
+
+This creates an C<import> method in the C<MooseX::Debugging>
+package. Since we are not actually exporting anything, we do not pass
+C<setup_import_methods> any parameters. However, we need to have an
+C<import> method to ensure that our C<init_meta> method is called.
+
+Then in our C<init_meta> method we have this line:
+
+      Moose->init_meta(%options);
+
+This is a bit of boilerplate that almost every extension will
+use. This ensures that the caller has a normal Moose metaclass
+I<before> we go and add traits to it.
+
+The C<< Moose->init_meta >> method does ensures that the caller has a
+sane metaclass, and we don't want to replicate that logic in our
+extension. If the C<< Moose->init_meta >> was already called (because
+the caller did C<use Moose> before using our extension), then calling
+C<< Moose->init_meta >> again is effectively a no-op.
+
 =head1 AUTHOR
 
 Dave Rolsky E<lt>autarch@urth.orgE<gt>