--- a/src/pyams_utils/tales.py	Fri Nov 18 16:47:09 2016 +0100
+++ b/src/pyams_utils/tales.py	Fri Nov 18 16:52:36 2016 +0100
@@ -47,74 +47,7 @@
 def render_extension(econtext, name):
     """TALES extension renderer
 
-    This renderer can be used to render an *extension:* TALES expression.
-    When this expression is encountered, the renderer is looking for an
-    :py:class:`ITALESExtension <pyams_utils.interfaces.tales.ITALESExtension>`
-    multi-adapter for the current *context*, *request* and *view*, for the current
-    *context* and *request*, or only for the current *context*, in this order.
-    If an adapter is found, the renderer call it's :py:func:`render` method with
-    the expression parameters as input parameters.
-
-    For example, the *metas* extension is an *ITALESExtension* adapter defined into
-    :py:mod:`pyams_skin.metas` module which can be used to include all required headers in
-    a page template. Extension is used like this in the page layout template:
-
-    .. code-block:: html
-
-        <tal:var replace="structure extension:metas" />
-
-    This extension is defined like this:
-
-    .. code-block:: python
-
-        from pyams_skin.interfaces.metas import IHTMLContentMetas
-        from pyams_utils.interfaces.tales import ITALESExtension
-        from pyramid.interfaces import IRequest
-
-        from pyams_utils.adapter import adapter_config, ContextRequestViewAdapter
-
-        @adapter_config(name='metas', context=(Interface, IRequest, Interface), provides=ITALESExtension)
-        class MetasTalesExtension(ContextRequestViewAdapter):
-            '''extension:metas TALES extension'''
-
-            def render(self, context=None):
-                if context is None:
-                    context = self.context
-                result = []
-                for name, adapter in sorted(self.request.registry.getAdapters((context, self.request, self.view),
-                                                                              IHTMLContentMetas),
-                                            key=lambda x: getattr(x[1], 'order', 9999)):
-                    result.extend([meta.render() for meta in adapter.get_metas()])
-                return '\n\t'.join(result)
-
-    Some TALES extension can require or accept arguments. For example, the *absolute_url* extension can accept
-    a context and a view name:
-
-    .. code-block:: html
-
-        <tal:var define="logo config.logo">
-            <img tal:attributes="src extension:absolute_url(logo, '++thumb++200x36.png');" />
-        </tal:var>
-
-    The extension is defined like this:
-
-    .. code-block:: python
-
-        from persistent.interfaces import IPersistent
-        from pyams_utils.interfaces.tales import ITALESExtension
-
-        from pyams_utils.adapter import adapter_config, ContextRequestViewAdapter
-        from pyramid.url import resource_url
-        from zope.interface import Interface
-
-        @adapter_config(name='absolute_url', context=(IPersistent, Interface, Interface), provides=ITALESExtension)
-        class AbsoluteUrlTalesExtension(ContextRequestViewAdapter):
-            '''extension:absolute_url(context, view_name) TALES extension'''
-
-            def render(self, context=None, view_name=None):
-                if context is None:
-                    context = self.context
-                return resource_url(context, self.request, view_name)
+    See :ref:`tales` for complete description.
     """
 
     def get_value(econtext, arg):