Merge pull request #34 "Don't use `is` to compare integers"

From: https://github.com/alex/pystache/commit/b2ae206d68961b8aef568ceaa3dd1274150ef23e
Into: issue_34

Fixed a bug which caused the unit tests related to rendering zeroes to fail
when using PyPy.  Using "is" to compare integers relies on an implementation
of CPython.  The operator "==" should be used instead.

pystache/template.py

@@ -166,7 +166,12 @@ class Template(object):
         raw = self.view.get(tag_name, '')
 
         # For methods with no return value
-        if not raw and raw is not 0:
+        #
+        # We use "==" rather than "is" to compare integers, as using "is" relies
+        # on an implementation detail of CPython.  The test about rendering
+        # zeroes fails on PyPy when using "is".
+        # See issue #34: https://github.com/defunkt/pystache/issues/34
+        if not raw and raw != 0:
             if tag_name == '.':
                 raw = self.view.context_list[0]
             else:

pystache/view.py

@@ -139,7 +139,11 @@ class View(object):
     def __getitem__(self, attr):
         val = self.get(attr, None)
 
-        if not val and val is not 0:
+        # We use "==" rather than "is" to compare integers, as using "is" relies
+        # on an implementation detail of CPython.  The test about rendering
+        # zeroes fails on PyPy when using "is".
+        # See issue #34: https://github.com/defunkt/pystache/issues/34
+        if not val and val != 0:
             raise KeyError("Key '%s' does not exist in View" % attr)
         return val