Refactoring in the way the parse function is invoked.

--HG--
branch : trunk
diff --git a/jinja2/compiler.py b/jinja2/compiler.py
index f0deeff..5179003 100644
--- a/jinja2/compiler.py
+++ b/jinja2/compiler.py
@@ -606,7 +606,7 @@
         )
         if overriden_closure_vars:
             self.fail('It\'s not possible to set and access variables '
-                      'derived from an outer scope! (affects: %s' %
+                      'derived from an outer scope! (affects: %s)' %
                       ', '.join(sorted(overriden_closure_vars)), node.lineno)
 
         # remove variables from a closure from the frame's undeclared