The implementation starts here: https://github.com/python/cpython/blob/ecb035cd14c11521276343397151929a94018a22/Objects/funcobject.c#L499
The argument clinic input specifying the signature is a few lines above. Clinic's output is here: https://github.com/python/cpython/blob/master/Objects/clinic/funcobject.c.h I suspect that the omission is just an oversight. You should probably just open a bug on bugs.python.org. If you feel like contributing code, not just bug reports, try working on a pull request! (See the devguide: https://devguide.python.org/) Good luck! On Fri, Oct 18, 2019 at 6:33 AM Gus Wiedey <guswie...@gmail.com> wrote: > I was recently playing around with decorators and experimenting with > defining a function's signature dynamically at runtime, and came across the > builtins.function class constructor (more easily accessible through the > types.FunctionType alias). I quickly realized, however, that even though > the constructor has a parameter (argdefs) that is used to specify default > values for the resulting function's positional arguments, there is no > corresponding parameter for keyword-only argument defaults. This seems like > a glaring omission, especially considering the fact that argdefs takes a > tuple that is directly assigned (unmodified) to the __defaults__ attribute. > I can't find any obvious reason why there shouldn't be a similar "kwdefs" > parameter that takes a dict and assigns it to __kwdefaults__. I downloaded > the cpython repo, made this change myself as proof-of-concept, and compiled > it, and it appears to work fine. This brings me to two questions: > > 1. Is there a reason for this disparity that I'm not seeing (e.g. breaking > some other feature), or is it just an oversight? > 2. If I wanted to submit this as an actual language change, would I need > to write a full PEP or is it small enough that it could go to the issue > tracker? (Note that the documentation says this constructor can vary > between implementations, so the change would only apply to cpython if that > matters.) > > Also, if this is the wrong place to ask this, please feel free to set me > straight; I'm completely new to this whole process, so any help on where to > start would be appreciated. > _______________________________________________ > Python-ideas mailing list -- python-ideas@python.org > To unsubscribe send an email to python-ideas-le...@python.org > https://mail.python.org/mailman3/lists/python-ideas.python.org/ > Message archived at > https://mail.python.org/archives/list/python-ideas@python.org/message/3ETG4HAKR2WQWAKAFCHU4UMC5X37OHKZ/ > Code of Conduct: http://python.org/psf/codeofconduct/ > -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
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