[Python-3000] hash as attribute/property

[Delaney, Timothy (Tim)]

Guido van Rossum wrote:

> The __hash__() method qualifies, which is why it's a tough call (I'll
> come back on that; I want to come up with a reason why __hash__()
> should remain a method). The iterator-getting example above doesn't
> qualify.

Yeah - I felt it was a borderline case, so thought it was a good case
for setting a precedent.

Pros for making it an attribute/property:

1. It should return the same value each time.

2. Faster access for many types.

Cons:

1. Gratuitous breakage with 2.x.

2. If it's a property, subclasses need to override the getter and
recreate the property if they want to change the hash of the object
(unless the base class uses a lazy property).

Tim Delaney