(Info-up): New arg SAME-FILE: don't move to different file.

(Info-next-preorder): Pass new arg to Info-up.
(Info-last-preorder): Likewise.
(Info-last-preorder): Don't follow the Prev if it's same as the Up.
Instead, follow it as the Up.

1 files changed, 13 insertions, 6 deletions

diff --git a/lisp/info.el b/lisp/info.el
index 46c18662a78..872bd830803 100644
--- a/lisp/info.el
+++ b/lisp/info.el
@@ -911,10 +911,15 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
   (interactive)
   (Info-goto-node (Info-extract-pointer "prev[ious]*" "previous")))
 
-(defun Info-up ()
-  "Go to the superior node of this node."
+(defun Info-up (&optional same-file)
+  "Go to the superior node of this node.
+If SAME-FILE is non-nil, do not move to a different Info file."
   (interactive)
-  (Info-goto-node (Info-extract-pointer "up"))
+  (let ((node (Info-extract-pointer "up")))
+    (and same-file
+         (string-match "^(" node)
+         (error "Up node is in another Info file"))
+    (Info-goto-node node))
   (Info-restore-point Info-history))
 
 (defun Info-last ()
@@ -1277,7 +1282,7 @@ N is the digit argument used to invoke this command."
   (interactive)
   (cond ((Info-no-error (Info-next-menu-item)))
         ((Info-no-error (Info-next)))
-        ((Info-no-error (Info-up))
+        ((Info-no-error (Info-up t))
          ;; Since we have already gone thru all the items in this menu,
          ;; go up to the end of this node.
          (goto-char (point-max))
@@ -1302,7 +1307,9 @@ N is the digit argument used to invoke this command."
                  ;; so we can scroll back through it.
                  (goto-char (point-max))))
          (recenter -1))
-        ((Info-no-error (Info-prev))
+        ((and (not (equal (Info-extract-pointer "up")
+                          (Info-extract-pointer "prev"))))
+         (Info-no-error (Info-prev))
          (goto-char (point-max))
          (while (Info-no-error
                  (Info-last-menu-item)
@@ -1310,7 +1317,7 @@ N is the digit argument used to invoke this command."
                  ;; so we can scroll back through it.
                  (goto-char (point-max))))
          (recenter -1))
-        ((Info-no-error (Info-up))
+        ((Info-no-error (Info-up t))
          (goto-char (point-min))
          (or (search-forward "\n* Menu:" nil t)
              (goto-char (point-max))))