Re: The *Warnings* buffer and undo

[Miles Bader <miles@gnu.org>]

I wrote:
> However in some other potential applications (someone mentioned
> customization buffers, where you probably want to restrict undo to the
> user-editable fields), things are not so simple, so having something
> which works at a primitive level (like "inhibit-undo") might be nice in
> general.

I think I slightly mis-read your message.  The method you mention --
looking at buffer-undo-list after the fact, and then removing some
entries and using them to fix up the rest of the entries -- sounds like
a very workable approach in lisp, since the to-be-discarded entries will
contain all the information you need.

A possible interface could be:

  (let ((keep-undo buffer-undo-list))

    ;; do some modifications which shouldn't be kept in the undo list
    (do-some-buffer-modifications)

    (discard-undo-entries keep-undo))

"discard-undo-entries" would just take a tail of the undo list as an
argument and discard everything before it (fixing up the rest).

-Miles

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