[Python-Dev] PEP 573 -- Module State Access from C Extension Methods

Petr Viktorin encukou at gmail.com
Wed Apr 25 14:33:09 EDT 2018


On 04/24/18 13:12, Jeroen Demeyer wrote:
> On 2018-04-24 16:34, Jeroen Demeyer wrote:
>> On the other hand, if you are passing the function object, then you can
>> get __self__ from it (unless it's an unbound method: in that case
>> __self__ is NULL and self is really args[0]). So there wouldn't be a
>> need for passing "self". I'm not saying that this is better than passing
>> "self" explicitly... I haven't yet decided what is best.
> 
> One thing I realized from PEP 573: the fact that __self__ for built-in 
> functions is set to the module is considered a feature. I never 
> understood the reason for it (and I don't know if the original reason 
> was the same as the reason in PEP 573).
> 
> If we want to continue supporting that and we also want to support 
> __get__ for built-in functions (to make them act as methods), then there 
> are really two "selfs": there is the "self" from the method (the object 
> that it's bound to) and the "self" from the built-in function (the 
> module). To support that, passing *both* the function and "self" seems 
> like the best way.

You're talking about functions with METH_BINDING here, right?
There the other "self" would be the defining module.
It might make sense to pass that also in the struct, rather than as an 
additional argument.
Perhaps "m_objclass" could point to the module in this case, or a new 
pointer could be added.


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