[Python-Dev] Fixing _PyEval_SliceIndex so that integer-like objects can be used

David Ascher david.ascher at gmail.com
Fri Feb 18 22:36:31 CET 2005

On Fri, 18 Feb 2005 13:28:34 -0800, Guido van Rossum
<gvanrossum at gmail.com> wrote:
> > Would it be possible to change
> >
> > _PyEval_SliceIndex  in ceval.c
> >
> > so that rather than throwing an error if the indexing object is not an
> > integer, the code first checks to see if the object has a
> > tp_as_number->nb_int method and calls it instead.
> I don't think this is the right solution; since float has that method,
> it would allow floats to be used as slice indices, but that's not
> supposed to work (to protect yourself against irreproducible results
> due to rounding errors).

I wonder if floats are the special case here, not "integer like objects".

I've never been particularly happy about the confusion between the two
roles of int() and it's C equivalents, i.e. casting and conversion.

More information about the Python-Dev mailing list