[Python-Dev] Expression optimizations

[Cesare Di Mauro]

On Mar, Feb 10, 2009 06:24 PM, Daniel Stutzbach wrote:
> On Tue, Feb 10, 2009 at 11:16 AM, Steve Holden <steve at holdenweb.com>
> wrote:
>
>> That's true, but the same *could* be said about the existing
>> optimizations for objects that define their own __contains__.
>>
>
> No, because there isn't a __not_contains__, so you cannot define the
> inverse
> operation differently.  "not a in b" and "a not in b" have exactly the
> same
> effects.
>

Interesting. So at least for "is" and "in" operators it is possible to
play with the "not" operator.

Thanks
Cesare