Add __self__ and __func__ for bound templates. Fixes #9

CHANGES.rst

@@ -14,7 +14,10 @@
 - Add the ``string`` and ``nocall`` functions for use inside Python
   expressions. See `issue 2
   <https://github.com/zopefoundation/z3c.pt/issues/2>`_.
-
+- Make bound page templates have ``__self__`` and ``__func__``
+  attributes to be more like Python 3 bound methods. (``im_func`` and
+  ``im_self`` remain available.) See `issue 9
+  <https://github.com/zopefoundation/z3c.pt/issues/9>`_.
 
 3.0 (2016-09-02)
 ================

src/z3c/pt/pagetemplate.py

@@ -278,24 +278,26 @@ class BoundPageTemplate(object):
     the class instance on access, which is implemented using this
     helper class."""
 
-    im_self = None
-    im_func = None
+    __self__ = None
+    __func__ = None
 
     def __init__(self, pt, render):
-        object.__setattr__(self, 'im_self', pt)
-        object.__setattr__(self, 'im_func', render)
+        object.__setattr__(self, '__self__', pt)
+        object.__setattr__(self, '__func__', render)
 
-    macros = property(lambda self: self.im_self.macros)
-    filename = property(lambda self: self.im_self.filename)
+    im_self = property(lambda self: self.__self__)
+    im_func = property(lambda self: self.__func__)
+    macros = property(lambda self: self.__self__.macros)
+    filename = property(lambda self: self.__self__.filename)
 
     def __call__(self, *args, **kw):
         kw.setdefault('args', args)
-        return self.im_func(**kw)
+        return self.__func__(**kw)
 
     def __setattr__(self, name, v):
         raise AttributeError("Can't set attribute", name)
 
     def __repr__(self):
         return "<%s.Bound%s %r>" % (
-            type(self.im_self).__module__,
-            type(self.im_self).__name__, self.filename)
+            type(self.__self__).__module__,
+            type(self.__self__).__name__, self.filename)

src/z3c/pt/tests/test_templates.py

@@ -238,7 +238,7 @@ def test_setattr(self):
         bound = pagetemplate.BoundPageTemplate(None, None)
         with self.assertRaisesRegexp(AttributeError,
                                      "Can't set attribute"):
-            setattr(bound, 'im_self', 42)
+            setattr(bound, '__self__', 42)
 
     def test_repr(self):
         # It requires the 'filename' attribute
@@ -248,3 +248,11 @@ class Template(object):
         bound = pagetemplate.BoundPageTemplate(Template(), 'render')
         self.assertEqual("<z3c.pt.tests.test_templates.BoundTemplate 'file.pt'>",
                          repr(bound))
+
+    def test_attributes(self):
+        func = object()
+        bound = pagetemplate.BoundPageTemplate(self, func)
+        self.assertIs(self, bound.im_self)
+        self.assertIs(self, bound.__self__)
+        self.assertIs(func, bound.im_func)
+        self.assertIs(func, bound.__func__)