On Wed, Oct 27, 2021 at 3:39 AM Erik Demaine <edema...@mit.edu> wrote: > > On Tue, 26 Oct 2021, Steven D'Aprano wrote: > > > def func(x=x, y=>x) # or func(x=x, @y=x) > > This makes me think of a "real" use-case for assigning all early-bound > defaults before late-bound defaults: consider using closure hacks (my main use > of early-bound defaults) together with late-bound defaults, as in > > ``` > for i in range(n): > def func(arg := expensive(i), i = i): > ... > ``` > > I think it's pretty common to put closure hacks at the end, so they don't get > in the way of the caller. (The intent is that the caller never specifies > those arguments.) But then it'd be nice to be able to use those variables in > the late-bound defaults. > > I can't say this is beautiful code, but it is an application and would > probably be convenient.
Got any realistic examples? Seems very hackish to me. > Perhaps most natural is to add a new introspection object, say LateDefault, > that can take place as a default value (but can't be used as an early-bound > default?), and has a __code__ attribute. > Yeah, I'll have to play with this. It may be necessary to wrap *both* types of default such that you can distinguish them. Effectively, instead of a tuple of values, you'd have a tuple of defaults, each one stating whether it's a value or a code block. ChrisA _______________________________________________ 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/DZVDQKPWDBBOTZ4ARLBNIS5NGSY7N2FK/ Code of Conduct: http://python.org/psf/codeofconduct/
