On Tue, Mar 16, 2021 at 11:59 AM Eric V. Smith <e...@trueblade.com> wrote:
> On 3/16/2021 10:06 AM, Ricky Teachey wrote: > > ... > I think I prefer it, too. But what about using something like > `mark=dataclasses.KW_ONLY` rather than `kw_only=True` (in the field > constructor)? So it isn't an on/off switch and as to leave open the door > for positional arguments? Is that door to be totally closed? I'm not here > to argue in favor of it necessarily, just asking whether we really want to > close the door more tightly against it than we have to. > > > I don't see how my proposal prohibits a future use of positional > arguments, much as '/' was added after '*' for positional arguments for > functions. > > Eric > Here I am only trying to help by pointing out a few things that might be worth considering. However I am FULLY willing to be told "Rick: we've been designing language features a long time and, trust me, none of this a big deal." :) It doesn't prohibit it, but choosing `kw_only` as the argument name (in both dataclasses.dataclass and dataclasses.field) semantically limits it to only being used as an on/off switch for a kw-only setting. Later, if it became desirable to add positional only, you'd need to add another separate on/off setting for it (say, `posit_only`) and then you'd end up in situations where the flag combos could be in conflict, and you have to check for that conflict: kw_only=True, posit_only=True The above would be an invalid combination. So it doesn't prohibit it but it makes it a bit harder to add it later. And is there another possible "setting".... possibly a bit exotic, maybe something that would end up being specific to dataclasses... that would also exclude OR require one or both of either/or kw_only and posit_only...? I am not sure, but maybe there is. And in that case you'd end up with a third on/off switch, and some other set of possibly ponderous checking: kw_only=True, exotic_setting=True posit_only=True, exotic_setting=True --- Ricky. "I've never met a Kentucky man who wasn't either thinking about going home or actually going home." - Happy Chandler
_______________________________________________ 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/7TI6GS6BFYA3TYAZHOVMZ7WSOBZROE57/ Code of Conduct: http://python.org/psf/codeofconduct/
