Re: Supporting newer Emacs features in older Emacs versions without warnings?

[Stefan Monnier]

Basil L. Contovounesios [2021-09-26 17:49:33] wrote:
> Stefan Monnier [2021-09-24 09:14 -0400] wrote:
>> Can you guys come up with an idea of how to change shortdoc.el so that
>> your package can do its job more easily and cleanly?
>> [ Ideally without having to use eval-after-load nor having to require
>> shortdoc.  ]
>
> Apart from eval-after-load, what other mechanisms do we have that can
> register information before a package is loaded?  There's obarray and
> there are hooks, is there something else?

For buffer-local info, the standard way is for the amjor mode to do

    (setq-local <foo> <bar>)

Example of <foo> include `font-lock-defaults` (back when font-lock was
not enabled by default), `outline-regexp`, `imenu-generic-expression`, ...

Here I think we want something that's not buffer-local, so we'd need
something else.  Not sure what's the best option.  Maybe

    (add-hook 'shortdoc-foo-functions #'...)

?

> The entrypoint command shortdoc-display-group could, every time it is
> invoked, scan obarray for certain symbol properties, or run a hook, to
> accumulate auxiliary shortdoc forms, in addition to those that were
> already permanently stored in shortdoc--groups.

That's also an option, yes (scanning `obarray` is fairly quick).


        Stefan