Added cookbook on differences whne using compiler passes in the framework

Author: richardmiller-zz

cookbook/service_container/compiler_passes.rst

@@ -0,0 +1,32 @@
+How to work with Compiler Passes in Bundles
+===========================================
+
+Compiler passes give you an opportunity to manipulate other service
+definitions that have been registered with the service container. You
+can read about how to create them in the components section ":doc:`/components/dependency_injection/compilation`".
+To register a compiler pass from a bundle you need to add it to the build
+method of the bundle definition class::
+
+    namespace Acme\MailerBundle;
+
+    use Symfony\Component\HttpKernel\Bundle\Bundle;
+    use Symfony\Component\DependencyInjection\ContainerBuilder;
+
+    use Acme\MailerBundle\DependencyInjection\Compiler\CustomCompilerPass;
+
+    class AcmeMailerBundle extends Bundle
+    {
+        public function build(ContainerBuilder $container)
+        {
+            parent::build($container);
+
+            $container->addCompilerPass(new CustomCompilerPass());
+        }
+    }
+
+One of the common tasks for compiler passes is to work with tagged services,
+read more about this in the components section  ":doc:`/components/dependency_injection/tags`".
+If you are using custom tags in a bundle then by convention, tag names consist
+of the name of the bundle (lowercase, underscores as separators), followed
+by a dot, and finally the "real" name, so the tag "transport" in the AcmeMailerBundle
+should be: ``acme_mailer.transport``.

cookbook/service_container/index.rst

@@ -6,4 +6,4 @@ Service Container
 
     event_listener
     scopes
-    tags
+    compiler_passes