This is great! Indeed, it works perfectly now.
I think using the margins is just much more elegant.

Although, I might have read about this behavior somewhere,
obviously, it was not clear to me that `erase-buffer` does not
remove the overlays. Maybe a warning/reminder about this could
 be added in the 'erase-buffer' docstring? What do you think?
I would be happy to create a patch for that (if desired).

Anyway, thanks a lot again Eli, for having a look at it.
Obviously, I really appreciate it.


On Sat, 25 Feb 2023 at 11:51, Eli Zaretskii <eliz@gnu.org> wrote:

> > From: dalanicolai <dalanicolai@gmail.com>
> > Date: Fri, 24 Feb 2023 21:53:35 +0100
> > Cc: emacs-devel@gnu.org
> >
> > B.t.w if someone want to have a look, I'll attach a smaller file here
> where
> > I have just removed about 200 pages of the book text data, so that it is
> > the file is much smaller, but there is still enough date to clearly show
> the
> > 'undesired' behavior.
> >
> > So now, Emacs will not 'hang', but there will still be a clear
> difference in time it
> > takes to update the buffer (between when window margins are displayed,
> > and when they are not).
>
> Your code overwhelms redisplay with an inconceivably huge number of
> overlays that are left from the previous iteration.  This one-line
> change makes the code work reasonably fast:
>
> (defun baleen-update2 ()
>   ;; (let ((query (minibuffer-contents)))
>   ;;   (with-current-buffer (get-buffer-create "*baleen*")
>   ;;     (erase-buffer)
>   ;;     (baleen-render (baleen-filter test2 query)))))
>   (let* ((query (minibuffer-contents))
>          (query-length (length query)))
>     (if (> (length previous-query) query-length)
>         (with-current-buffer (get-buffer-create "*baleen*")
>           (erase-buffer)
>           (baleen-render (cdr (alist-get query baleen-results nil nil
> #'string=))))
>       (let* ((parent-results (unless (< query-length 2)
>                                (alist-get (substring query 0 -1)
> baleen-results nil nil #'string=)))
>              (current-results (if parent-results
>                                   (baleen-filter parent-results query)
>                                 (unless (string-empty-p query)
> (baleen-filter test2 query)))))
>         (when current-results
>           (with-current-buffer (get-buffer-create "*baleen*")
>             (remove-overlays) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>             (erase-buffer)
>             (baleen-render current-results))
>           (cl-pushnew (cons query current-results) baleen-results :test
> #'string= :key #'car))
>
>         (setq previous-query query)))))
>