2 files changed, 22 insertions, 9 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 8ac744bb980..8da19539c9a 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2012-11-17  Andreas Politz  <politza@fh-trier.de>
+
+        * ibuffer.el (ibuffer-mark-forward, ibuffer-unmark-forward)
+        (ibuffer-unmark-backward, ibuffer-mark-interactive): Support plain
+        prefix and negative numeric prefix args (Bug#12795).
+
 2012-11-17  Stephen Berman  <stephen.berman@gmx.net>
 
         * play/gamegrid.el (gamegrid-add-score-with-update-game-score-1):
diff --git a/lisp/ibuffer.el b/lisp/ibuffer.el
index 72ca189e9d5..4e0ac1a4856 100644
--- a/lisp/ibuffer.el
+++ b/lisp/ibuffer.el
@@ -1362,24 +1362,27 @@ group."
 (defun ibuffer-mark-forward (arg)
   "Mark the buffer on this line, and move forward ARG lines.
 If point is on a group name, this function operates on that group."
-  (interactive "P")
-  (ibuffer-mark-interactive arg ibuffer-marked-char 1))
+  (interactive "p")
+  (ibuffer-mark-interactive arg ibuffer-marked-char))
 
 (defun ibuffer-unmark-forward (arg)
   "Unmark the buffer on this line, and move forward ARG lines.
 If point is on a group name, this function operates on that group."
-  (interactive "P")
-  (ibuffer-mark-interactive arg ?\s 1))
+  (interactive "p")
+  (ibuffer-mark-interactive arg ?\s))
 
 (defun ibuffer-unmark-backward (arg)
   "Unmark the buffer on this line, and move backward ARG lines.
 If point is on a group name, this function operates on that group."
-  (interactive "P")
-  (ibuffer-mark-interactive arg ?\s -1))
+  (interactive "p")
+  (ibuffer-unmark-forward (- arg)))
 
-(defun ibuffer-mark-interactive (arg mark movement)
+(defun ibuffer-mark-interactive (arg mark &optional movement)
   (ibuffer-assert-ibuffer-mode)
   (or arg (setq arg 1))
+  ;; deprecated movement argument
+  (when (and movement (< movement 0))
+    (setq arg (- arg)))
   (ibuffer-forward-line 0)
   (ibuffer-aif (get-text-property (point) 'ibuffer-filter-group-name)
       (progn
@@ -1389,8 +1392,12 @@ If point is on a group name, this function operates on that group."
     (let ((inhibit-read-only t))
       (while (> arg 0)
         (ibuffer-set-mark mark)
-        (ibuffer-forward-line movement t)
-        (setq arg (1- arg))))))
+        (ibuffer-forward-line 1 t)
+        (setq arg (1- arg)))
+      (while (< arg 0)
+        (ibuffer-forward-line -1 t)
+        (ibuffer-set-mark mark)
+        (setq arg (1+ arg))))))
 
 (defun ibuffer-set-mark (mark)
   (ibuffer-assert-ibuffer-mode)