[Python-Dev] Can we make METH_FASTCALL public, from Python 3.7? (ref: PEP 579

Jeroen Demeyer J.Demeyer at UGent.be
Thu Jun 21 01:57:49 EDT 2018

On 2018-06-20 17:42, INADA Naoki wrote:
> I don't have any idea about changing METH_FASTCALL more.
> If Victor and Serhiy think so, and PyPy maintainers like it too, I want
> to make it public
> as soon as possible.

There are two different things here:

The first is documenting METH_FASTCALL such that everybody can create 
built-in functions using the METH_FASTCALL signature. I think that the 
API for METH_FASTCALL (without or with METH_KEYWORDS) is fine, so I 
support making it public. This is really just a documentation issue, so 
I see no reason why it couldn't be added to 3.7.0 if we're fast.

The API for calling functions using the FASTCALL convention is more of a 
mess though. There are functions taking keyword arguments as dict and 
functions taking them as tuple. As I mentioned in PEP 580, I'd like to 
merge these and simply allow either a dict or a tuple. Since this would 
require an API change, this won't be for 3.7.0.


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