Re: Multiple next-error sources

[Stefan Monnier]

> I strongly dislike this approach.  It conflates customization points with
> implementation details.  Hook variables clearly separate the two ideas.

foo-function *is* a customization point and not an implementation detail.

That's the difference between using add-function on a foo-function (a
customization point) and using advice-add on some function (some
implementation detail).

> There's also no buffer-local add-function equivalent.

Of course there is:

   (add-function :before-until (local 'next-error-function) #'my-function)


-- Stefan