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

[npostavs]

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.  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.