Does Python need a semantics for and/or over generators ? was : 'xor' operator?

[Grant Edwards]

In article <yNDu8.13611$Ji7.6515 at atlpnn01.usenetserver.com>, Steve Holden wrote:
> "Grant Edwards" <grante at visi.com> wrote in message
> news:YwCu8.32367$vm6.5103753 at ruti.visi.com...
>> In article <3CBABA71.3040909 at geneva-link.ch>, Boris Borcic wrote:
>>
>> > For the shortcut semantics, we'd like to have :
>> >      a xor b
>> >
>> > behave exactly like :
>> >      (not b and a) or (not a and b)
>>
>> I don't understand how that's a shortcut (assuming that means
>> the same thing as short-circuit).  You have to evaluate both
>> operands of an xor operator.  There is no possibly way to
>> short-circuit the expression so that only one is evaluated.
>
> But they each might be evaluated *twice* in the given
> equivalent expression if the existing Boolean operators didn't
> short-circuit.

I see.   Of course if there _were_ an xor operator, that
wouldn't be a problem...

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