Three PEP updates:

* Correct the pure python implementation.
* Link to an implementation patch on SF.
* Remove the proposed application of __reverse__ to enumerate().

pep-0322.txt

@@ -67,11 +67,10 @@ reverse iteration is to specify it in a forward direction and then say
 The implementation could be as simple as::
 
     def reversed(x):
-        try:
-            return x.__reversed__()
-        except AttributeError:
-            pass
-        if hasattr(x, "has_key"):
+        if hasattr(x, 'reversed'):
+            for elem x.__reversed__():
+		yield x
+        if hasattr(x, 'keys'):
             raise ValueError("mappings do not support reverse iteration")
         i = len(x)
         while i > 0:
@@ -81,6 +80,8 @@ The implementation could be as simple as::
 No language syntax changes are needed.  The proposal is fully backwards
 compatible.
 
+A C implementation and unit tests are at:  http://www.python.org/sf/834422
+
 
 Alternative Method Names
 ========================
@@ -102,12 +103,6 @@ This allows *reverse()* to be applied to objects that do not have
 __getitem__() and __len__() but still have some useful way of
 providing reverse iteration.
 
-For example, using this protocol, *enumerate()* can be extended to 
-support reversal whenever the underlying iterator supports it also::
-
-    >>> list(reversed(enumerate("abc")))
-    [(2, 'c'), (1, 'b'), (0, 'a')]
-
 
 Real World Use Cases
 ====================