bug#9258: 24.0.50; image-next-line doesnt allow omitting arg

bug#9258: 24.0.50; image-next-line doesnt allow omitting arg

[joakim]

This bug report will be sent to the Bug-GNU-Emacs mailing list
and the GNU bug tracker at debbugs.gnu.org.  Please check that
the From: line contains a valid email address.  After a delay of up
to one day, you should receive an acknowledgement at that address.

Please write in English if possible, as the Emacs maintainers
usually do not have translators for other languages.

Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':


(defun image-next-line (&optional n)
  "Scroll image in current window upward by N lines.
Stop if the bottom edge of the image is reached."
  (interactive "p")
  (cond ((= n 0) nil)
	((< n 0)
	 (image-set-window-vscroll (max 0 (+ (window-vscroll) n))))
	(t
	 (let* ((image (image-get-display-property))
		(edges (window-inside-edges))
		(win-height (- (nth 3 edges) (nth 1 edges)))
		(img-height (ceiling (cdr (image-display-size image)))))
	   (image-set-window-vscroll (min (max 0 (- img-height win-height))
					  (+ n (window-vscroll))))))))

declaration says n is optional but nil will fail on the numeric tests.
so, either n isn't optional or the cond rearanged.

                                          
If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
/usr/local/share/emacs/24.0.50/etc/DEBUG.


In GNU Emacs 24.0.50.20 (x86_64-unknown-linux-gnu, GTK+ Version 3.0.11)
 of 2011-08-03 on localhost.localdomain
Windowing system distributor `Fedora Project', version 11.0.11003000
configured using `configure  '--with-xwidgets' '--without-gnutls' '--enable-asserts' '--with-x-toolkit=gtk3''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  shell-dirtrack-mode: t
  predictive-which-dict-mode: t
  paredit-mode: t
  desktop-save-mode: t
  erc-truncate-mode: t
  erc-track-mode: t
  erc-track-minor-mode: t
  erc-spelling-mode: t
  erc-ring-mode: t
  erc-pcomplete-mode: t
  erc-netsplit-mode: t
  erc-log-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-autojoin-mode: t
  erc-autoaway-mode: t
  ido-everywhere: t
  erc-stamp-mode: t
  erc-match-mode: t
  show-paren-mode: t
  erc-smiley-mode: t
  erc-irccontrols-mode: t
  eldoc-mode: t
  recentf-mode: t
  grab-and-drag-mode: t
  yas/global-mode: t
  yas/minor-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Recent input:

-- 
Joakim Verona

bug#9258: 24.0.50; image-next-line doesnt allow omitting arg

[Stefan Monnier]

> (defun image-next-line (&optional n)
>   "Scroll image in current window upward by N lines.
> Stop if the bottom edge of the image is reached."
>   (interactive "p")
>   (cond ((= n 0) nil)
> 	((< n 0)
> 	 (image-set-window-vscroll (max 0 (+ (window-vscroll) n))))
> 	(t
> 	 (let* ((image (image-get-display-property))
> 		(edges (window-inside-edges))
> 		(win-height (- (nth 3 edges) (nth 1 edges)))
> 		(img-height (ceiling (cdr (image-display-size image)))))
> 	   (image-set-window-vscroll (min (max 0 (- img-height win-height))
> 					  (+ n (window-vscroll))))))))

> declaration says n is optional but nil will fail on the numeric tests.
> so, either n isn't optional or the cond rearanged.

Please just make it mandatory.


        Stefan

bug#9258: 24.0.50; image-next-line doesnt allow omitting arg

[Lars Magne Ingebrigtsen]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> Please just make it mandatory.

Ok; done.

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/