Subject: bug#35536: 27.0.50; Expose buffer's marker list to Elisp

From: Mauro Aranda <[email-masked]>
Date: Fri, 3 May 2019 20:01:18 -0300

>>> I have yet to see a use-case for marker-list which can't be engineered
>>> in a different way (other than as a replacement for the obsolete
>>> buffer-has-markers-at, FWIW).
>>
>> Well, the discussions you cited did express requirements whose
>> implementation with the existing facilities was either inconvenient or
>> restricted.  If these problems are still relevant, then why not try
>> providing some primitives to help them?
>
> A save+restore primitive like the one you suggested in your other
> message sounds like it might do the trick without having to expose a
> buffer's marker list to Lisp.

Indeed.  I thought Martin was talking about something like this in his post
in bug#18.  Given a region where text is going to be replaced, save the
positions of markers that would be affected because of the delete+insert,
and then restore them.

>> IOW, let me turn the table and ask: why would a Lisp program want to
>> get a list of all the markers in a buffer, especially those not
>> created from Lisp?
>
> As I say above, I don't have any use-cases which specifically need to
> expose a buffer's marker list to Lisp, as opposed to using some other
> approach.  The main call for marker-list in bug#18 could probably be
> better solved with a different primitive.
>

When I said I didn't find anything at the Lisp level to get the markers,
that didn't fully express my thoughts.  I didn't mean it as a call for a
function to get that information (and certainly, I don't see a use for
getting information about markers created internally).  What I meant was
that I thought about that way of restoring markers, but had no way of
working on it (at least not with my current knowledge of C).

Best regards,
Mauro.