Home Original page

[Python-Dev] C-level duck typing

"Martin v. Löwis" martin at v.loewis.de
Wed May 16 20:29:26 CEST 2012 
> In our specific case the value would be an offset added to the
> PyObject*, and there we would find a pointer to a C function (together
> with a 64-bit signature), and calling that C function (after checking
> the 64 bit signature) is our final objective.

And what the C function does really is faster than the lookup through
a dictionary? I find that hard to believe.

>> I still think this is out of scope for python-dev. If this is something
>> you want to be able to do for Python 2.4 as well, then you don't need
>> any change to Python - you can do whatever you come up with for all
>> Python versions, no need to (or point in) changing Python 3.4 (say).
>
> We can go ahead and hijack tp_flags bit 22 to make things work in
> existing versions. But what if Python 3.8 then starts using that bit for
> something else?

Use flag bit 23 in Python 3.8. You know at compile time what Python
version you have.

>
>> As this is apparently only relevant to speed fanatics, too, I suggest
>> that you check how fast PyPI works for you.
>
> Did you mean PyPy?

Oops, yes - Freudian slip :-)

Regards,
Martin
More information about the Python-Dev mailing list