no unbound methods in py3k

Terry Reedy tjreedy at udel.edu
Thu Oct 9 21:06:17 CEST 2008


Thomas Heller wrote:
> Christian Heimes schrieb:
>> Thomas Heller wrote:
>>> but this is very ugly, imo.  Is there another way?
>>> The raw_func instances that I have are not descriptors (they
>>> do not implement a __get__() method...)
>> I've written PyInstanceMethod_Type for this use case. It's not (yet) 
>> available for Python code. Barry hasn't decided whether he should expose 
>> the type so late in the release cycle or not. See 
>> http://bugs.python.org/issue3787 and 
>> http://docs.python.org/dev/3.0/c-api/method.html?highlight=pyinstancemethod#PyInstanceMethod_Type
>>
> 
> Ok, so one has to write an extension to access or expose it.
> 
> Oh, wait - there's ctypes:
> 
> Python 3.0rc1 (r30rc1:66507, Sep 18 2008, 14:47:08) [MSC v.1500 32 bit (Intel)] on win32
> Type "help", "copyright", "credits" or "license" for more information.
>>>> from ctypes import *
>>>> pythonapi.PyInstanceMethod_New.restype = py_object
>>>> pythonapi.PyInstanceMethod_New.argtypes = [py_object]
>>>> instancemethod = pythonapi.PyInstanceMethod_New
>>>>
>>>> class Example:
> ...     pass
> ...
>>>> Example.id = instancemethod(id)
>>>>
>>>> x = Example()
>>>> x.id()
> 12597296
>>>> id(x)
> 12597296

A pyCapi module that exposed via ctypes useful C functions not otherwise 
accessible, with predefinition of restype and argtypes and anything else 
needed, might make a nice addition to PyPI if not the stdlib.  You have 
done two here and I believe others have posted others.

tjr




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