Re: [PATCH v3] RFC: eldoc-documentation-functions hook

[Stefan Monnier <monnier@iro.umontreal.ca>]

>>>>> Applied with some wording changes as 5811404
>>>> I don't think we have reached any consensus.
>>> The problem is not just that it introduces a gratuitous incompatiblity,
>>> but that it's a regression since you can't use things like :around nor
>>> choose precedence (as in add-function's `depth') with add-hook.
> There was never a need.

But your change removes the possibility.  Just because it hasn't been
needed yet doesn't mean it won't be needed in the future.  After all,
eldoc has not seen much use so far.

> Usually foo-function holds a function symbol.  If one had a desire to
> add-hook on foo-function whose value is #'bar, then perhaps bar should
> run a hook; but then perhaps foo-function is just a layer of indirection
> and you really should just have a hook.

foo-function *is* a hook.

>> - C-h v foo-function RET gives a value that's unreadable.   That is true
>> and we should improve it.  I don't think there's anything really hard
>> about doing so, so it's a transient motivation and it'd be better to
>> fix `C-h v' than to circumvent the problem by using foo-functions.
> Yes, we should not have to read bytecode or (at best) RTFS to decipher
> what foo-function is doing.

100% Agreement.

> Which is great if that flexibility is even necessary.

The great thing about foo-function (along with add-function) is that you
don't need to guess beforehand if it's going to be necessary.

> The verbosity of writing advice isn't so bad; using advice even when the
> circumstance doesn't call for it is.  To cite an example, is the
> following somehow different from just using setq-local?
> http://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/textmodes/tex-mode.el#n1262

Yes, the use of add-function here is overkill.  But this exact same
setting would be just right for a minor mode (where using setq-local
and kill-local-variable is painful and brittle).

> PS: I'd have suggested a more graceful change like that of
> pre-redisplay-function(s)
> http://git.savannah.gnu.org/cgit/emacs.git/commit/?id=84e0b7d

As you can see, I'm not completely dogmatic about forcing the use
of foo-function in place of foo-functions everywhere.  In the case of
pre-redisplay-function, the function does not return any value, so
there's not much point in using things like :around, or :before-until.


        Stefan