bug#28257: 26.0.50; [PATCH] expose eldoc functions in a hook

[Mark Oteiza <mvoteiza@udel.edu>]

On 28/08/17 at 09:05pm, npostavs@users.sourceforge.net wrote:
>Mark Oteiza <mvoteiza@udel.edu> writes:
>
>> If both the buffer mode's documentation function and the function in the
>> default-value return non-nil at a point, execution stops at the
>> :before-until function, analogous to run-hook-with-args-until-success.
>>
>> I want to see both results.  See what eldoc-documentation-compose does.
>>
>> To do what is described above, not only does one have to write some
>> wrapper function to advise eldoc-documentation-function buffer-locally,
>> but also one has to hook into any/every mode that might add its own doc
>> function.
>
>Ah, I think I understand now.  The patch makes it easier to customize
>the composition of all eldoc-documentation-functions at the cost of
>making it more difficult for the individual mode to decide how its own
>doc function will compose.

Correct.

> Could be a worthwhile tradeoff (especially
>since there currently aren't any individual mode eldoc functions using
>anything apart from :before-until, afaik); I'm on the fence about this.

Not in emacs, at least.  In elpa, ggtags uses :after-until.  The only
3rd party packages--that I can think of right now--that implement eldoc
functions just use setq-local (elpy and geiser).