bug#41531: 27.0.91; Better handle asynchronous eldoc backends

[João Távora]

Dmitry Gutov <dgutov@yandex.ru> writes:

>> But if we really, really wanted to, it's easy to get rid of the
>> arguments, too, with a variation to the callback technique.  I just
>> don't think it's worth it: a technique is a technique.
>
> The variation that I showed in my little patch a month ago?

No, to be clear that was not a variation to the callback technique.  One
way is simply to passing the callback as a special variable (and there
are more ways.)

The rest of your long email hints that you've misunderstood what this
change to Eldoc is accomplishing.  I'm afraid I've done all I can to
explain it, including docstrings, NEWS entries, commit messages and
going through your previous very long code review.  I understand you
expected a futures library would come with this change, but it does not,
not for now.  I've explained that is only a technique, but in this last
email you conflate every issue with it again.  My position is: if there
really is value in them, futures will soon be in Emacs.  Let's follow
Stefan advice, it's good advice.  I might even work a bit on futures
myself.

Best,
João