(comint-previous-input): Don't clobber input line when moving off either

end of the input history ring.
(comint-delete-input): New function, used by `comint-previous-input' and
others.
(comint-previous-matching-input): Use `coming-delete-input'. Save the
partial input if leaving the edit line.  Goto point-max before deleting
input to avoid partial input fragments hanging around.
(comint-restore-input): New function, used by `comint-previous-input',
and bound to "C-c C-j".

1 files changed, 39 insertions, 7 deletions

diff --git a/lisp/comint.el b/lisp/comint.el
index 5ab00354f80..a44e252ca97 100644
--- a/lisp/comint.el
+++ b/lisp/comint.el
@@ -465,6 +465,7 @@ executed once when the buffer is created."
     (define-key map "\C-c\C-l" 	  'comint-dynamic-list-input-ring)
     (define-key map "\C-c\C-n" 	  'comint-next-prompt)
     (define-key map "\C-c\C-p" 	  'comint-previous-prompt)
+    (define-key map "\C-c\C-j" 	  'comint-restore-input)
     (define-key map "\C-c\C-d" 	  'comint-send-eof)
     (define-key map "\C-c\C-s" 	  'comint-write-output)
     (define-key map "\C-c." 	  'comint-insert-previous-argument)
@@ -558,6 +559,9 @@ This is to support the command \\[comint-get-next-from-history].")
   "Non-nil if you are accumulating input lines to send as input together.
 The command \\[comint-accumulate] sets this.")
 
+(defvar comint-stored-incomplete-input nil
+  "Stored input for history cycling.")
+
 (put 'comint-replace-by-expanded-history 'menu-enable 'comint-input-autoexpand)
 (put 'comint-input-ring 'permanent-local t)
 (put 'comint-input-ring-index 'permanent-local t)
@@ -638,6 +642,7 @@ Entry to this mode runs the hooks on `comint-mode-hook'."
   (make-local-variable 'comint-scroll-to-bottom-on-input)
   (make-local-variable 'comint-move-point-for-output)
   (make-local-variable 'comint-scroll-show-maximum-output)
+  (make-local-variable 'comint-stored-incomplete-input)
   ;; This makes it really work to keep point at the bottom.
   (make-local-variable 'scroll-conservatively)
   (setq scroll-conservatively 10000)
@@ -1015,6 +1020,16 @@ See also `comint-read-input-ring'."
 	(t
 	 arg)))
 
+(defun comint-restore-input ()
+  "Restore unfinished input."
+  (interactive)
+  (when comint-input-ring-index
+    (comint-delete-input)
+    (when (> (length comint-stored-incomplete-input) 0)
+      (insert comint-stored-incomplete-input)
+      (message "Input restored"))
+    (setq comint-input-ring-index nil)))
+
 (defun comint-search-start (arg)
   "Index to start a directional search, starting at `comint-input-ring-index'."
   (if comint-input-ring-index
@@ -1035,9 +1050,18 @@ Moves relative to `comint-input-ring-index'."
 				arg)))
 
 (defun comint-previous-input (arg)
-  "Cycle backwards through input history."
+  "Cycle backwards through input history, saving input."
   (interactive "*p")
-  (comint-previous-matching-input "." arg))
+  (if (and comint-input-ring-index 
+	   (or		       ;; leaving the "end" of the ring
+	    (and (< arg 0)		; going down
+		 (eq comint-input-ring-index 0))
+	    (and (> arg 0)		; going up
+		 (eq comint-input-ring-index 
+		     (1- (ring-length comint-input-ring)))))
+	   comint-stored-incomplete-input)
+      (comint-restore-input)
+    (comint-previous-matching-input "." arg)))
 
 (defun comint-next-input (arg)
   "Cycle forwards through input history."
@@ -1077,6 +1101,14 @@ Moves relative to START, or `comint-input-ring-index'."
     (if (string-match regexp (ring-ref comint-input-ring n))
 	n)))
 
+(defun comint-delete-input ()
+  "Delete all input between accumulation or process mark and point."
+  (delete-region
+   ;; Can't use kill-region as it sets this-command
+   (or  (marker-position comint-accum-marker)
+	(process-mark (get-buffer-process (current-buffer))))
+   (point-max)))
+
 (defun comint-previous-matching-input (regexp n)
   "Search backwards through input history for match for REGEXP.
 \(Previous history elements are earlier commands.)
@@ -1088,13 +1120,13 @@ If N is negative, find the next or Nth next match."
     ;; Has a match been found?
     (if (null pos)
 	(error "Not found")
+      ;; If leaving the edit line, save partial input
+      (if (null comint-input-ring-index)	;not yet on ring
+	  (setq comint-stored-incomplete-input
+		(funcall comint-get-old-input)))
       (setq comint-input-ring-index pos)
       (message "History item: %d" (1+ pos))
-      (delete-region
-       ;; Can't use kill-region as it sets this-command
-       (or  (marker-position comint-accum-marker)
-	    (process-mark (get-buffer-process (current-buffer))))
-       (point))
+      (comint-delete-input)
       (insert (ring-ref comint-input-ring pos)))))
 
 (defun comint-next-matching-input (regexp n)