[#1786] Adding documentation for Twig namespaced paths support

Author: weaverryan

book/templating.rst

@@ -376,6 +376,11 @@ When working with template inheritance, here are some tips to keep in mind:
 Template Naming and Locations
 -----------------------------
 
+.. versionadded:: 2.2
+    Namespaced path support was added in 2.2, allowing for template names
+    like ``@AcmeDemoBundle/layout.html.twig``. See :doc:`/cookbook/templating/namespaced_paths`
+    for more details.
+
 By default, templates can live in two different locations:
 
 * ``app/Resources/views/``: The applications ``views`` directory can contain

cookbook/map.rst.inc

@@ -134,6 +134,7 @@
 * :doc:`/cookbook/templating/index`
 
   * :doc:`/cookbook/templating/global_variables`
+  * :doc:`/cookbook/templating/namespaced_paths`
   * :doc:`/cookbook/templating/PHP`
   * :doc:`/cookbook/templating/twig_extension`
   * :doc:`/cookbook/templating/render_without_controller`

cookbook/templating/index.rst

@@ -5,6 +5,7 @@ Templating
     :maxdepth: 2
 
     global_variables
+    namespaced_paths
     PHP
     twig_extension
     render_without_controller

cookbook/templating/namespaced_paths.rst

@@ -0,0 +1,86 @@
+.. index::
+   single: Templating; Namespaced Twig Paths
+
+How to use and Register namespaced Twig Paths
+=============================================
+
+.. versionadded:: 2.2
+    Namespaced path support was added in 2.2.
+
+Usually, when you refer to a template, you'll use the ``MyBundle:Subdir:filename.html.twig``
+format (see :ref:`template-naming-locations`).
+
+Twig also natively offers a feature called "namespaced paths", and support
+is built-in automatically for all of your bundles.
+
+
+Take the following paths as an example:
+
+.. code-block:: jinja
+
+    {% extends "AcmeDemoBundle::layout.html.twig" %}
+    {% include "AcmeDemoBundle:Foo:bar.html.twig" %}
+
+With namespaced paths, the following works as well:
+
+.. code-block:: jinja
+
+    {% extends "@AcmeDemo/layout.html.twig" %}
+    {% include "@AcmeDemo/Foo/bar.html.twig" %}
+
+Both paths are valid and functional by default in Symfony2.
+
+.. tip::
+
+    As an added bonus, the namespaced syntax is faster.
+
+Registering your own namespaces
+-------------------------------
+
+You can also register your own custom namespaces. Suppose that you're using
+some third-party library that includes Twig templates that live in
+``vendor/acme/foo-project/templates``. First, register a namespace for this
+directory:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        # app/config/config.yml
+        twig:
+            # ...
+            paths:
+                "%kernel.root_dir%/../vendor/acme/foo-bar/templates": foo_bar
+
+    .. code-block:: xml
+
+        <!-- app/config/config.xml -->
+
+        <?xml version="1.0" ?>
+        <container xmlns="http://symfony.com/schema/dic/services"
+                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                   xmlns:twig="http://symfony.com/schema/dic/twig"
+                >
+
+            <twig:config debug="%kernel.debug%" strict-variables="%kernel.debug%">
+                <twig:path namespace="foo_bar">%kernel.root_dir%/../vendor/acme/foo-bar/templates</twig:path>
+            </twig:config>
+        </container>
+
+
+    .. code-block:: php
+
+        // app/config/config.php
+        $container->loadFromExtension('twig', array(
+            'paths' => array(
+                '%kernel.root_dir%/../vendor/acme/foo-bar/templates' => 'foo_bar'
+            );
+        ));
+
+The registered namespace is called ``foo_bar``, which refers to the
+``vendor/acme/foo-project/templates`` directory. Assuming there's a file
+called ``sidebar.twig`` in that directory, you can use it easily:
+
+.. code-block:: jinja
+
+    {% include '@foo_bar/side.bar.twig` %}