added loopcontrols extension and added unittests for it
--HG--
branch : trunk
diff --git a/jinja2/nodes.py b/jinja2/nodes.py
index 27c9ddb..ad39903 100644
--- a/jinja2/nodes.py
+++ b/jinja2/nodes.py
@@ -118,8 +118,10 @@
def iter_fields(self, exclude=None, only=None):
"""This method iterates over all fields that are defined and yields
- ``(key, value)`` tuples. Optionally a parameter of ignored fields
- can be provided.
+ ``(key, value)`` tuples. Per default all fields are returned, but
+ it's possible to limit that to some fields by providing the `only`
+ parameter or to exclude some using the `exclude` parameter. Both
+ should be sets or tuples of field names.
"""
for name in self.fields:
if (exclude is only is None) or \