[Python-Dev] Comparing PEP 576 and PEP 580 (original) (raw)

Jeroen Demeyer J.Demeyer at UGent.be
Wed Jul 4 11:59:42 EDT 2018

On 2018-07-04 03:31, INADA Naoki wrote:

I think both PEPs are relying on FASTCALL calling convention, and can't be accepted until FASTCALL is stable & public.

First of all, the fact that FASTCALL has not been made public should not prevent from discussing those PEPs and even making a (provisional?) decision on them. I don't think that the precise API of FASTCALL really matters that much.

More importantly, I don't think that you can separate making FASTCALL public from PEP 576/580. As you noted in [1], making FASTCALL public means more than just documenting METH_FASTCALL.

In particular, a new API should be added for calling objects using the FASTCALL convention. Here I mean both an abstract API for arbitrary callables as well as a specific API for certain classes. Since PEP 580 (and possibly also PEP 576) proposes changes to the implementation of FASTCALL, it makes sense to design the public API for FASTCALL after it is clear which of those PEPs (if any) is accepted. If we fix the FASTCALL API now, it might not be optimal when either PEP 576 or PEP 580 is accepted.

Jeroen.

[1] https://mail.python.org/pipermail/python-dev/2018-June/153956.html

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