2017-11-29 11:14 GMT+03:00 Nick Coghlan <ncoghlan@gmail.com>:
It's OK to say "the use case exists, but I still don't want that particular syntax for it in Python" (I'm personally inclined to agree with you on that front). It's not OK to try to claim there are no use cases where the status quo is awkward enough to become irritating (since it's an empirically false statement that you don't need to be making).
If the problem with the proposed syntax, but there are cases for use, it may be worth to bikeshed one more time? 2017-11-29 9:08 GMT+03:00 Steven D'Aprano <steve@pearwood.info>: I'd much prefer to read, write and teach the version with ?? over the
status quo.
Since the proposed semantics is more similar to the idea of "or", may be it is better to consider something like: timeout then local_timeout then global_timeout I do not know how much this is a frequent case to be worthy of a keyword. With kind regards, -gdg 2017-11-29 11:14 GMT+03:00 Nick Coghlan <ncoghlan@gmail.com>:
On 29 November 2017 at 16:13, David Mertz <mertz@gnosis.cx> wrote:
Strong -1 still from me. Too special case for syntax. Just write a function 'first_non_none()' that can perfectly will handle the need.
That's the equivalent of SQL's COALESCE, and it's insufficient for the same reason "and" and "or" are syntax rather than builtins: the function form doesn't provide short-circuiting behaviour.
As far as utility goes, I put it in a similar category to matrix multiplication: if you don't need it, you don't need it, but when you do need it, you need it a *lot*.
The use case where these operations come up is when you're working with partially structured hierarchical data (*cough*JSON*cough*). In those kinds of structures, None is frequently used as a marker to say "this entire subtree is missing", and you either want to propagate that None, or else replace it with something else (and the "something else" may be a network call to a different service, so you definitely don't want to do it if you don't need to).
So I'd remind folks to try to avoid the "I don't need this, so nobody needs this" mistake. It's OK to say "the use case exists, but I still don't want that particular syntax for it in Python" (I'm personally inclined to agree with you on that front). It's not OK to try to claim there are no use cases where the status quo is awkward enough to become irritating (since it's an empirically false statement that you don't need to be making).
Cheers, Nick.
-- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/