[Cython] PEP 3135 -- New Super

[mark florisson]

On 7 July 2011 17:09, Vitja Makarov <vitja.makarov at gmail.com> wrote:
> 2011/7/6 Vitja Makarov <vitja.makarov at gmail.com>:
>> 2011/7/6 Stefan Behnel <stefan_ml at behnel.de>:
>>> Vitja Makarov, 06.07.2011 09:05:
>>>>
>>>> 2011/7/6 Stefan Behnel<stefan_ml at behnel.de>:
>>>>>
>>>>> Stefan Behnel, 05.07.2011 10:04:
>>>>>>
>>>>>> Vitja Makarov, 05.07.2011 09:17:
>>>>>>>
>>>>>>> 2011/7/5 Stefan Behnel:
>>>>>>>>
>>>>>>>> Vitja Makarov, 05.07.2011 08:21:
>>>>>>>>>
>>>>>>>>> I was thinking about implementing new super() with no arguments.
>>>>>>>>
>>>>>>>> http://trac.cython.org/cython_trac/ticket/696
>>>>>>>>
>>>>>>>>> The problem is where to store __class__, I see two options here:
>>>>>>>>>
>>>>>>>>> 1. Add func_class member to CyFunction, this way __class__ will be
>>>>>>>>> private and not visible for inner functions:
>>>>>>>>> 2. Put it into closure
>>>>>>>>
>>>>>>>> The second option has the advantage of requiring the field only when
>>>>>>>> super()
>>>>>>>> is used, whereas the first impacts all functions.
>>>>>>>>
>>>>>>>> I would expect that programs commonly have a lot more functions than
>>>>>>>> specifically methods that use a no-argument call to super(), so this
>>>>>>>> may
>>>>>>>> make a difference.
>>>>>>>>
>>>>>>>
>>>>>>> So, now classes are created the following way:
>>>>>>>
>>>>>>> class_dict = {}
>>>>>>> class_dict.foo = foo_func
>>>>>>> class = CreateClass(class_dict)
>>>>>>>
>>>>>>> So after class is created I should check its dict for CyFunction
>>>>>>> members (maybe only ones that actually require __class__)
>>>>>>> and set __class__:
>>>>>>>
>>>>>>> for value in class.__dict__.itervalues():
>>>>>>> if isinstance(value, CyFunction) and value.func_class is WantClass:
>>>>>>> value.func_class = class
>>>>>>>
>>>>>>> Btw, first way requires cyfunction signature change, it would accept
>>>>>>> cyfunction object as first argument.
>>>>>>
>>>>>> We currently pass the binding (i.e. owning) object, right?
>>>>>
>>>>> So, how would this work for methods? We need to pass the 'self' object
>>>>> there, which the CyFunction doesn't know. If anything, it only knows the
>>>>> class it was defined in, which doesn't help here.
>>>>
>>>> From PEP: "super() is equivalent to: super(__class__,<firstarg>)"
>>>
>>> I wasn't speaking of super(). What I meant, was: how do we pass 'self' when
>>> we pass the CyFunction object as the first argument?
>>>
>>
>>
>> Oh, ok. Now we pass closure or nothing in self. So method's self is
>> passed via tuple.
>> Instancemethod do this for us. Now CyFucntion uses PyCFunction_Call we
>> can override this and change signature of cyfunction to:
>>
>> PyObject func(CyFunction *func, PyObject *self, PyObject *args,
>> PyObject *kwargs);
>>
>> This way we should implement new instancemethod type.
>>
>
> I've add support for new super() for cdef classes here:
> https://github.com/vitek/cython/compare/_new_super
>
> Pure python classes would require my _bindings branch.
>

I also need that branch to continue my work on fused types. The naming
suggests I can't pull from it and start building on top of it? Did you
have any plans to review it Stefan? Otherwise I won't mind giving it a
go.

> --
> vitja.
> _______________________________________________
> cython-devel mailing list
> cython-devel at python.org
> http://mail.python.org/mailman/listinfo/cython-devel
>