bug#26624: 26.0.50; Generalized variable `buffer-local-value' does't restore local flag

[Lars Ingebrigtsen]

Michael Heerdegen <michael_heerdegen@web.de> writes:

>> :variable (electric-indent-mode .
>>            (lambda (val) (setq-local electric-indent-mode val)))
>
> Looks good - similar specs are already used in other places.

Now pushed to Emacs 29 (and I've made buffer-local-value obsolete again
as a generalized variable).

> BTW: I find the definition of `electric-indent-local-mode' inelegant:
> the handling of the variable is split between the :variable spec and the
> body.  The body enables the global mode and sets the global variable
> back to nil - quite hackish.

Yes, it's not ideal at all.

> Anyway, if this is needed in more places it cries for a
> `define-localized-mode'.

I hope it's not used a lot -- we'd rather have modes work in the
opposite direction.  That is, the mode is local, and then we have
globalized versions of it.