[Cython] PEP 3135 -- New Super

[Vitja Makarov]

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.

-- 
vitja.