Kevin Ryde <user42@zip.com.au> writes:

> (defun my-gnus-summary-exit (&optional temporary)
>   "Like `gnus-summary-exit', but sometimes preserve point in *Group*."
>   (interactive "P")
>   (if (save-excursion
>         (with-current-buffer "*Group*"
>           (beginning-of-line)
>           (looking-at "^ U\\|^. *0:")))
>       (my-gnus-summary-exit-nonext temporary)
>     (gnus-summary-exit temporary)))
>
> (defun my-gnus-summary-exit-nonext (&optional temporary)
>   "Like `gnus-summary-exit', but don't move in *Group*."
>   (interactive "P")
>   (let ((group gnus-newsgroup-name))
>     (gnus-summary-exit temporary)
>     (gnus-summary-jump-to-group group)))

Well, you now can use (not tested at all) :

(defun my-gnus-summary-exit (&optional temporary)
  (interactive "P")
  (let ((gnus-summary-next-group-on-exit
          (with-current-buffer "*Group*"
            (not (string-match "^ U\\|^. *0:" (thing-at-point 'line))))))
    (gnus-summary-exit temporary)))

Yeah! Less characters, less functions, more free disk space and memory!
Gorgeous, isn't it? :-)

> I guess it's personal preference, but maybe there'd be a clean way to
> have a notion of "reading in sequence" versus revisiting, and only
> advance for the former.

On the other hand, I don't know if it's good to add customization
mechanisms for summary exit that much.

-- 
 |   Michaël `Micha' Cadilhac       |  La meilleure façon                    |
 |   http://michael.cadilhac.name   |     de ne pas avancer,                 |
 |   JID/MSN:                       |  c'est de suivre une idée fixe.        |
 `----  michael.cadilhac@gmail.com  |          -- Jacques Prévert       -  --'