[Python-Dev] __index__ clipping
Travis E. Oliphant
oliphant.travis at ieee.org
Fri Aug 11 09:51:04 CEST 2006
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.
-Travis
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