[Python-Dev] Python-versus-CPython question for __mul__ dispatch

[Nick Coghlan]

On 15 May 2015 at 16:53, Nathaniel Smith <njs at pobox.com> wrote:
> On Thu, May 14, 2015 at 9:29 PM, Guido van Rossum <guido at python.org> wrote:
>> I expect you can make something that behaves like list by defining __mul__
>> and __rmul__ and returning NotImplemented.
>
> Hmm, it's fairly tricky, and part of the trick is that you can never
> return NotImplemented (because you have to pretty much take over and
> entirely replace the normal dispatch rules inside __mul__ and
> __rmul__), but see attached for something I think should work.
>
> So I guess this is just how Python's list, tuple, etc. work, and PyPy
> and friends need to match...

No, CPython is broken.

Cheers,
Nick.

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