[Python-Dev] __index__ clipping

[Nick Coghlan]

Travis E. Oliphant wrote:
> Travis E. Oliphant wrote:
>> Here is my C-API proposal
>>
>> 1) PyIndex_Check(obj)
>>
>>    Similar to PyIter_Check(obj) as it just checks for whether or not the 
>> object can call nb_index.  Actually implemented as a macro.
>>
>> 2) PyObject* PyNumber_Index(obj)
>>
>>    Simple interface around nb_index that calls it if possible and returns
>>    TypeError if not (or if the result does not end up in an exact
>>    int-or-long
>>
>> 3) Py_ssize_t PyNumber_AsSsize_t(obj, err)
>>
>>     This converts the object to a Py_ssize_t by using the nb_index call
>>     if possible.  The err argument is a Python error object and specifies
>>     what error should be raised should the conversion from Int-or-Long to
>>     Py_ssize_t cause Overflow.
>>
>>     If err is NULL, then no error will be raised and the result will be 
>> clipped.  Other-wise the corresponding error will be set.  Internally 
>> PyExc_IndexError and PyExc_OverflowError will be the errors used.
>>
> 
> This proposal is implemented as patch 1538606 
> http://sourceforge.net/tracker/index.php?func=detail&aid=1538606&group_id=5470&atid=305470

This interface is a lot simpler to explain and use than the one in my patch, 
and more in tune with the rest of the C API.

I had a minor documentation suggestion which I put on the tracker item, but 
other than that +1 on using Travis's patch instead of mine (I've already 
rejected my own tracker item).

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
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