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The examples of set operations in http://docs.python.org/dev/library/stdtypes#dictionary-view-objects don't work in the current 2.7 trunk:
-> ./python.exe
Python 2.7b1+ (trunk:80084:80085M, Apr 14 2010, 21:17:06) 
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> dishes = {'eggs': 2, 'sausage': 1, 'bacon': 1, 'spam': 500}
>>> keys = dishes.viewkeys()
>>> keys & {'eggs', 'bacon', 'salad'}
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for &: 'dict_keys' and 'set'
>>> keys | {'eggs'}
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for |: 'dict_keys' and 'set'
Is this a documentation bug, and set operations are only supported in 3.x? Or does the code need to be fixed?
(Assigned to Alexandre, since he committed the backport patch; please feel free to reassign. Marking as release blocker; if it's a documentation bug, we can lower the priority.)

It is a bug.
First, the dictviews_as_number is broken; the field for classic division was removed in 3.x, so everything is shifted by one. I included a patch to fix this.
Unfortunately, this isn't enough to fix the issue. There seems to be some overly restrictive type checking going on in the method wrappers. However, I don't have the time to investigate this further today. I should be able to check this next weekend.

I found the issue. The view types didn't have Py_TPFLAGS_CHECKTYPES set, so the types were using the old-style binary operators.
Here's a patch that fixes the issue. Please review.

The patch looks fine. I verified that the new tests pass on trunk and py3k. I am attaching a patch for py3k with a forward port of set opereations and repr tests.

Committed in r80749 and r80751 (for py3k).
Thank you!

(commenting on a closed bug, because I'm not sure it should be re-opened)
While coming up with examples, I found a weird inconsistency. Was it intentional for viewkeys() and viewitems() to support set operations, but not viewvalues()? 
>>> d1 = dict((i*10, chr(65+i)) for i in range(26))
>>> d2 = dict((i**.5, i) for i in range(1000))
>>> d1.viewkeys() | set('abc')
set([0, 130, 10, 140, 20, 150, 30, 160, 40, 170, 50, 180, 60, 190, 70, 200, 80, 210, 90, 220, 'a', 'c', 'b', 100, 230, 110, 240, 120, 250])
>>> d1.viewitems() | set('abc')
set([(70, 'H'), (0, 'A'), ....)
>>> d1.viewvalues() | set('abc')
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for |: 'dict_values' and 'set' 
>>> d1.viewvalues() | d2.viewvalues()
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for |: 'dict_values' and 'dict_values'

The fix is easy, I think; just add Py_TPFLAGS_CHECKTYPES to the PyDictValues_Type's definition.

Why do you expect dict_values to support set operations? Dict values unlike keys are not sets, they are more like lists. Set operations of dict_values are not supported in 3.x either.

Ah, of course! It didn't occur to me that .values() isn't necessarily a set.

FWIW, this agrees with the specs in _abcoll which show KeysView and ItemsView as sets but not ValuesView.