Make view mode more similar to `less'.

Changed documentation for most commands.
(view-scroll-auto-exit): New variable, replaces view-mode-auto-exit.
(view-mode-auto-exit): Variable deleted.
(view-mode): Doesn't only toggle `view-mode', it also calls
view-mode-enter or view-mode-exit.
(view-buffer, view-buffer-other-window): New argument exit-action.
(view-file, view-file-other-window, view-buffer-other-window)
(view-buffer, view-mode-enter): Changed method used to restore
windows when leaving view mode.
(view-mode-exit): New function.
(view-return-to-alist): New variable.
(view-return-here, view-exit-position): Variables deleted.
(view-remove-frame-by-deleting, view-exit-all-windows-at-exit):
New option variables.
(view-page-size, view-half-page-size): New variables.
(view-scroll-size): Var deleted; replaced by the previous two.
(view-mode-map): Make the bindings inside defvar.
Added new commands and new key bindings.
Added view-mode-exit to `change-major-mode-hook' to always leave
view mode when changing major mode.
(view-file-other-frame,	view-buffer-other-frame): New commands.
(View-leave, View-kill-and-leave, View-exit, View-exit-and-edit)
(View-quit, View-quit-all): new commands for leaving view mode.
(view-exit): Function deleted.
(View-goto-percent, View-scroll-to-buffer-end): New commands.
(view-try-extend-at-buffer-end): New option variable.

(View-scroll-page-forward, View-scroll-page-backward)
(View-scroll-page-forward-set-page-size)
(View-scroll-page-backward-set-page-size, View-scroll-line-forward)
(View-scroll-line-backward, View-scroll-half-page-forward)
(View-scroll-half-page-backward)
(View-revert-buffer-scroll-page-forward): New commands.

(View-scroll-lines-forward, View-scroll-lines-backward)
(View-scroll-lines-forward-set-scroll-size)
(View-scroll-one-more-line): Commands deleted.

(view-scroll-lines, view-end-message, view-page-size-default)
(view-set-half-page-size-default, view-really-at-end)
(view-recenter): New functions.
(view-scroll-size): Variable deleted.

(View-search-regexp-forward, View-search-regexp-backward)
(View-search-last-regexp-forward, View-search-last-regexp-backward)
(view-search): ! and @ are special at beginning of regexp.
(view-search-no-match-lines): New function.

1 files changed, 717 insertions, 304 deletions

diff --git a/lisp/view.el b/lisp/view.el
index bbc168b6f9c..89cace0e0ad 100644
--- a/lisp/view.el
+++ b/lisp/view.el
@@ -1,6 +1,6 @@
 ;;; view.el --- peruse file or buffer without editing.
 
-;; Copyright (C) 1985, 1989, 1994, 1995 Free Software Foundation, Inc.
+;; Copyright (C) 1985, 1989, 1994, 1995, 1997 Free Software Foundation, Inc.
 
 ;; Author: K. Shane Hartman
 ;; Maintainer: FSF
@@ -26,6 +26,21 @@
 
 ;; This package provides the `view' minor mode documented in the Emacs
 ;; user's manual.
+;; View mode entry and exit is done through the functions view-mode-enter
+;; and view-mode-exit. Use these functions to enter or exit view-mode from
+;; emacs lisp programs.
+;; We use both view- and View- as prefix for symbols. View- is used as
+;; prefix for commands that have a key binding. view- is used for commands
+;; without key binding. The purpose of this is to make it easier for a
+;; user to use command name completion.
+
+;;; Suggested key bindings:
+;;
+;; (define-key ctl-x-4-map "v" 'view-file-other-window)  ; ^x4v
+;; (define-key ctl-x-5-map "v" 'view-file-other-frame)  ; ^x5v
+;;
+;; You could also bind view-file, view-buffer, view-buffer-other-window and
+;; view-buffer-other-frame to keys.
 
 ;;; Code:
 
@@ -33,33 +48,71 @@
 (defvar view-highlight-face 'highlight
    "*The overlay face used for highlighting the match found by View mode search.")
 
+;; `view-mode-auto-exit' is replaced by the following global variable which
+;; only says if scrolling past buffer end should leave view mode or not, it
+;; doesn't say if leaving view mode should restore windows or not. The latter
+;; is now controlled by the presence of a value in `view-return-to-alist'.
+;;;###autoload
+(defvar view-scroll-auto-exit nil
+  "*Non-nil means scrolling past the end of buffer exits View mode.
+nil means attempting to scroll past the end of the buffer,
+only rings the bell and gives a message on how to leave.")
+
+;;;###autoload
+(defvar view-try-extend-at-buffer-end nil
+ "*Non-nil means try load more of file when reaching end of buffer.")
+
+;;;###autoload
+(defvar view-remove-frame-by-deleting nil
+  "*Determine how to remove a not needed frame.
+If nil, make an icon of the frame. If non-nil, delete the frame.")
+
+;;;###autoload
+(defvar view-exit-all-windows-at-exit nil
+  "*Non-nil means restore all windows displaying buffer.
+Commands that restore windows apply to all windows displaying buffer.
+Buffer is removed from all windows displaying it, by using information in
+`view-return-to-alist' if that is available, otherwise by using
+`replace-buffer-in-windows'.")
+
 (defvar view-mode nil "Non-nil if View mode is enabled.")
 (make-variable-buffer-local 'view-mode)
 
-(defvar view-mode-auto-exit nil
-  "Non-nil means scrolling past the end of buffer exits View mode.
-Some commands, such as \\[view-file], set this to t locally;
-the only way to override that is to set it to nil using `view-mode-hook'.")
-
-(make-variable-buffer-local 'view-mode-auto-exit)
+(defvar view-mode-hook nil
+  "Normal hook run when starting to view a buffer or file.")
 
 (defvar view-old-buffer-read-only nil)
 (make-variable-buffer-local 'view-old-buffer-read-only)
+
 (defvar view-old-Helper-return-blurb)
 (make-variable-buffer-local 'view-old-Helper-return-blurb)
 
-(defvar view-scroll-size nil)
-(make-variable-buffer-local 'view-scroll-size)
+(defvar view-page-size nil
+  "Default number of lines to scroll by View page commands.
+If nil then the local value of this is initially set to window size.")
+(make-variable-buffer-local 'view-page-size)
 
-(defvar view-last-regexp nil)
-(make-variable-buffer-local 'view-last-regexp)
+(defvar view-half-page-size nil
+  "Default number of lines to scroll by View half page commands.
+If nil then the local value of this is initially set to half window size.")
+(make-variable-buffer-local 'view-half-page-size)
 
-(defvar view-exit-action nil)
+(defvar view-last-regexp nil)
+(make-variable-buffer-local 'view-last-regexp) ; Global is better???
+
+(defvar view-return-to-alist nil
+  "What to do with selected window and where to go when leaving View mode.
+Added to by view-mode-enter when entering View mode.
+See RETURN-TO-ALIST argument of function `view-mode-exit' for format of
+view-return-to-alist.")
+(make-variable-buffer-local 'view-return-to-alist)
+
+(defvar view-exit-action nil
+  "\\<view-mode-map>
+nil or a function with one argument (a buffer) called at exit of view mode.
+The \\[view-file] and \\[view-file-other-window] commands may set this to
+`kill-buffer'.")
 (make-variable-buffer-local 'view-exit-action)
-(defvar view-return-here nil)
-(make-variable-buffer-local 'view-return-here)
-(defvar view-exit-position nil)
-(make-variable-buffer-local 'view-exit-position)
 
 (defvar view-overlay nil
   "Overlay used to display where a search operation found its match.
@@ -70,243 +123,427 @@ This is local in each buffer, once it is used.")
     (setq minor-mode-alist
 	  (cons '(view-mode " View") minor-mode-alist)))
 
-(defvar view-mode-map nil)
-(if view-mode-map
-    nil
-  (setq view-mode-map (make-keymap))
-  ;; We used to call suppress-keymap here, but that isn't good in a minor mode.
-  ;; Self-inserting characters will beep anyway, since the buffer is read-only,
-  ;; and we should not interfere with letters that serve as useful commands.
-  (define-key view-mode-map "q" 'view-exit)
-  (define-key view-mode-map "<" 'beginning-of-buffer)
-  (define-key view-mode-map ">" 'end-of-buffer)
-  (define-key view-mode-map "\ev" 'View-scroll-lines-backward)
-  (define-key view-mode-map "\C-v" 'View-scroll-lines-forward)
-  (define-key view-mode-map " " 'View-scroll-lines-forward)
-  (define-key view-mode-map "\C-?" 'View-scroll-lines-backward)
-  (define-key view-mode-map "\n" 'View-scroll-one-more-line)
-  (define-key view-mode-map "\r" 'View-scroll-one-more-line)
-  (define-key view-mode-map "z" 'View-scroll-lines-forward-set-scroll-size)
-  (define-key view-mode-map "g" 'View-goto-line)
-  (define-key view-mode-map "=" 'what-line)
-  (define-key view-mode-map "." 'set-mark-command)
-  (define-key view-mode-map "'" 'View-back-to-mark)
-  (define-key view-mode-map "@" 'View-back-to-mark)  
-  (define-key view-mode-map "x" 'exchange-point-and-mark)
-  (define-key view-mode-map "h" 'describe-mode)
-  (define-key view-mode-map "?" 'describe-mode)
-  (define-key view-mode-map "s" 'isearch-forward)
-  (define-key view-mode-map "r" 'isearch-backward)
-  (define-key view-mode-map "/" 'View-search-regexp-forward)
-  (define-key view-mode-map "\\" 'View-search-regexp-backward)
-  ;; This conflicts with the standard binding of isearch-regexp-forward
-  (define-key view-mode-map "\e\C-s" 'View-search-regexp-forward)
-  (define-key view-mode-map "\e\C-r" 'View-search-regexp-backward)  
-  (define-key view-mode-map "n" 'View-search-last-regexp-forward)
-  (define-key view-mode-map "p" 'View-search-last-regexp-backward)
-  )
+;; Define keymap inside defvar to make it easier to load changes.
+(defvar view-mode-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map "C" 'View-kill-and-leave)
+    (define-key map "c" 'View-leave)
+    (define-key map "Q" 'View-quit-all)
+    (define-key map "E" 'View-exit-and-edit)
+;    (define-key map "v" 'View-exit)
+    (define-key map "e" 'View-exit)
+    (define-key map "q" 'View-quit)
+;    (define-key map "N" 'View-search-last-regexp-backward)
+    (define-key map "p" 'View-search-last-regexp-backward)
+    (define-key map "n" 'View-search-last-regexp-forward)
+;    (define-key map "?" 'View-search-regexp-backward) ; Less does this.
+    (define-key map "\\" 'View-search-regexp-backward)
+    (define-key map "/" 'View-search-regexp-forward)
+    (define-key map "r" 'isearch-backward)
+    (define-key map "s" 'isearch-forward)
+    (define-key map "m" 'point-to-register)
+    (define-key map "'" 'register-to-point)
+    (define-key map "x" 'exchange-point-and-mark)
+    (define-key map "@" 'View-back-to-mark)  
+    (define-key map "." 'set-mark-command)
+    (define-key map "%" 'View-goto-percent)
+;    (define-key map "G" 'View-goto-line-last)
+    (define-key map "g" 'View-goto-line)
+    (define-key map "=" 'what-line)
+    (define-key map "F" 'View-revert-buffer-scroll-page-forward)
+;    (define-key map "k" 'View-scroll-line-backward)
+    (define-key map "y" 'View-scroll-line-backward)
+;    (define-key map "j" 'View-scroll-line-forward)
+    (define-key map "\n" 'View-scroll-line-forward)
+    (define-key map "\r" 'View-scroll-line-forward)
+    (define-key map "u" 'View-scroll-half-page-backward)
+    (define-key map "d" 'View-scroll-half-page-forward)
+    (define-key map "z" 'View-scroll-page-forward-set-page-size)
+    (define-key map "w" 'View-scroll-page-backward-set-page-size)
+;    (define-key map "b" 'View-scroll-page-backward)
+    (define-key map "\C-?" 'View-scroll-page-backward)
+;    (define-key map "f" 'View-scroll-page-forward)
+    (define-key map " " 'View-scroll-page-forward)
+    (define-key map "o" 'View-scroll-to-buffer-end)
+    (define-key map ">" 'end-of-buffer)
+    (define-key map "<" 'beginning-of-buffer)
+    (define-key map "-" 'negative-argument)
+    (define-key map "9" 'digit-argument)
+    (define-key map "8" 'digit-argument)
+    (define-key map "7" 'digit-argument)
+    (define-key map "6" 'digit-argument)
+    (define-key map "5" 'digit-argument)
+    (define-key map "4" 'digit-argument)
+    (define-key map "3" 'digit-argument)
+    (define-key map "2" 'digit-argument)
+    (define-key map "1" 'digit-argument)
+    (define-key map "0" 'digit-argument)
+    (define-key map "H" 'describe-mode)
+    (define-key map "?" 'describe-mode)	; Maybe do as less instead?
+    (define-key map "h" 'describe-mode)
+    map))
 
 (or (assq 'view-mode minor-mode-map-alist)
     (setq minor-mode-map-alist
 	  (cons (cons 'view-mode view-mode-map) minor-mode-map-alist)))
 
+;; Always leave view mode before changing major mode.
+;; This is to guarantee that the buffer-read-only variable is restored.
+(add-hook 'change-major-mode-hook 'view-mode-exit)
+
+;;; Commands that enter or exit view mode.
 
 ;;;###autoload
 (defun view-file (file-name)
   "View FILE in View mode, returning to previous buffer when done.
-The usual Emacs commands are not available; instead,
+Emacs commands editing the buffer contents are not available; instead,
 a special set of commands (mostly letters and punctuation)
 are defined for moving around in the buffer.
 Space scrolls forward, Delete scrolls backward.
-For list of all View commands, type ? or h while viewing.
+For list of all View commands, type H or h while viewing.
 
 This command runs the normal hook `view-mode-hook'."
   (interactive "fView file: ")
-  (let ((old-buf (current-buffer))
-	(had-a-buf (get-file-buffer file-name))
-	(buf-to-view (find-file-noselect file-name)))
-    ;; This used to pass t as second argument,
-    ;; but then the buffer did not show up in the Buffers menu.
-    (switch-to-buffer buf-to-view had-a-buf)
-    (view-mode-enter old-buf
-		     (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
-			  'kill-buffer))))
+  (let ((had-a-buf (get-file-buffer file-name)))
+    (view-buffer (find-file-noselect file-name)
+		 (and (not had-a-buf) 'kill-buffer))))
 
 ;;;###autoload
 (defun view-file-other-window (file-name)
-  "View FILE in View mode in other window.
-Return to previous buffer when done.
-The usual Emacs commands are not available; instead,
+  "View FILE in View mode in another window.
+Return that window to its previous buffer when done.
+Emacs commands editing the buffer contents are not available; instead,
 a special set of commands (mostly letters and punctuation)
 are defined for moving around in the buffer.
 Space scrolls forward, Delete scrolls backward.
-For list of all View commands, type ? or h while viewing.
+For list of all View commands, type H or h while viewing.
 
 This command runs the normal hook `view-mode-hook'."
-  (interactive "fView file: ")
-  (let ((old-arrangement (current-window-configuration))
-	(had-a-buf (get-file-buffer file-name))
-	(buf-to-view (find-file-noselect file-name)))
-    (switch-to-buffer-other-window buf-to-view)
-    (view-mode-enter old-arrangement
-		     (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
-			  'kill-buffer))))
+  (interactive "fIn other window view file: ")
+  (let ((had-a-buf (get-file-buffer file-name)))
+    (view-buffer-other-window (find-file-noselect file-name) nil
+			      (and (not had-a-buf) 'kill-buffer))))
 
 ;;;###autoload
-(defun view-buffer (buffer-name)
-  "View BUFFER in View mode, returning to previous buffer when done.
-The usual Emacs commands are not available; instead,
+(defun view-file-other-frame (file-name)
+  "View FILE in View mode in another frame.
+Maybe delete other frame and/or return to previous buffer when done.
+Emacs commands editing the buffer contents are not available; instead,
 a special set of commands (mostly letters and punctuation)
 are defined for moving around in the buffer.
 Space scrolls forward, Delete scrolls backward.
-For list of all View commands, type ? or h while viewing.
+For list of all View commands, type H or h while viewing.
 
 This command runs the normal hook `view-mode-hook'."
+  (interactive "fIn other frame view file: ")
+  (let ((had-a-buf (get-file-buffer file-name)))
+    (view-buffer-other-frame (find-file-noselect file-name) nil
+			     (and (not had-a-buf) 'kill-buffer))))
+
+
+;;;###autoload
+(defun view-buffer (buffer-name &optional exit-action)
+  "View BUFFER in View mode, returning to previous buffer when done.
+Emacs commands editing the buffer contents are not available; instead,
+a special set of commands (mostly letters and punctuation)
+are defined for moving around in the buffer.
+Space scrolls forward, Delete scrolls backward.
+For list of all View commands, type H or h while viewing.
+
+This command runs the normal hook `view-mode-hook'.
+
+Optional argument EXIT-ACTION is either nil or a function with buffer as
+argument. This function is called when finished viewing buffer.
+Use this argument instead of explicitly setting `view-exit-action'."
+
   (interactive "bView buffer: ")
-  (let ((old-buf (current-buffer)))
-    (switch-to-buffer buffer-name t)
-    (view-mode-enter old-buf nil)))
+  (let ((undo-window (list (window-buffer) (window-start) (window-point))))
+    (switch-to-buffer buffer-name)
+    (view-mode-enter (cons (selected-window) (cons nil undo-window))
+		     exit-action)))
 
 ;;;###autoload
-(defun view-buffer-other-window (buffer-name not-return)
+(defun view-buffer-other-window
+  (buffer-name &optional not-return exit-action)
   "View BUFFER in View mode in another window.
-Return to previous buffer when done, unless NOT-RETURN is non-nil.
+Return to previous buffer when done, unless optional NOT-RETURN is non-nil.
+Emacs commands editing the buffer contents are not available; instead,
+a special set of commands (mostly letters and punctuation)
+are defined for moving around in the buffer.
+Space scrolls forward, Delete scrolls backward.
+For list of all View commands, type H or h while viewing.
+
+This command runs the normal hook `view-mode-hook'.
+
+Optional argument EXIT-ACTION is either nil or a function with buffer as
+argument. This function is called when finished viewing buffer.
+Use this argument instead of explicitly setting `view-exit-action'."
+  (interactive "bIn other window view buffer:\nP")
+  (let* ((win				; This window will be selected by
+	  (get-lru-window))		; switch-to-buffer-other-window below.
+	 (return-to
+	  (and (not not-return)
+	       (cons (selected-window)
+		     (if (eq win (selected-window))
+			 t			; Has to make new window.
+		       (list 
+			(window-buffer win)	; Other windows old buffer.
+			(window-start win)
+			(window-point win)))))))
+    (switch-to-buffer-other-window buffer-name)
+    (view-mode-enter (and return-to (cons (selected-window) return-to))
+		     exit-action)))
 
-The usual Emacs commands are not available in View mode; instead,
+;;;###autoload
+(defun view-buffer-other-frame
+  (buffer-name &optional not-return exit-action)
+  "View BUFFER in View mode in another frame.
+Return to previous buffer when done, unless optional NOT-RETURN is non-nil.
+Emacs commands editing the buffer contents are not available; instead,
 a special set of commands (mostly letters and punctuation)
 are defined for moving around in the buffer.
 Space scrolls forward, Delete scrolls backward.
-For list of all View commands, type ? or h while viewing.
+For list of all View commands, type H or h while viewing.
 
-This command runs the normal hook `view-mode-hook'."
-  (interactive "bView buffer:\nP")
-  (let ((return-to (and not-return (current-window-configuration))))
-    (switch-to-buffer-other-window buffer-name)
-    (view-mode-enter return-to)))
+This command runs the normal hook `view-mode-hook'.
+
+Optional argument EXIT-ACTION is either nil or a function with buffer as
+argument. This function is called when finished viewing buffer.
+Use this argument instead of explicitly setting `view-exit-action'."
+  (interactive "bView buffer in other frame: \nP")
+  (let ((return-to
+	 (and (not not-return) (cons (selected-window) t)))) ; Old window.
+    (switch-to-buffer-other-frame buffer-name)
+    (view-mode-enter (and return-to (cons (selected-window) return-to))
+		     exit-action)))
 
 ;;;###autoload
 (defun view-mode (&optional arg)
-  "Toggle View mode.
-With a prefix argument, turn View mode on if the argument is >= zero
-and off if it is not.
-
-If you use this function to turn on View mode, then subsequently
-\"exiting\" View mode does nothing except turn View mode off.  The
-other way to turn View mode on is by calling `view-mode-enter';
-that is what Lisp programs usually use.
-
-Letters do not insert themselves.  Instead these commands are provided.
-Most commands take prefix arguments.  Commands dealing with lines
-default to \"scroll size\" lines (initially size of window).
-Search commands default to a repeat count of one.
-
-M-< or <	move to beginning of buffer.
-M-> or >	move to end of buffer.
-C-v or Space	scroll forward lines.
-M-v or DEL	scroll backward lines.
-CR or LF	scroll forward one line (backward with prefix argument).
-z		like Space except set number of lines for further
-		   scrolling commands to scroll by.
-C-u and Digits	provide prefix arguments.  `-' denotes negative argument.
-=		prints the current line number.
-g		goes to line given by prefix argument.
-/ or M-C-s	searches forward for regular expression
-\\ or M-C-r	searches backward for regular expression.
-n		searches forward for last regular expression.
-p		searches backward for last regular expression.
-C-@ or .	set the mark.
-x		exchanges point and mark.
-C-s or s	do forward incremental search.
-C-r or r	do reverse incremental search.
-@ or '		return to mark and pops mark ring.
-		  Mark ring is pushed at start of every
-		  successful search and when jump to line to occurs.
-		  The mark is set on jump to buffer start or end.
-? or h		provide help message (list of commands).
-\\[help-command]		provides help (list of commands or description of a command).
-C-n		moves down lines vertically.
-C-p		moves upward lines vertically.
-C-l		recenters the screen.
-q		exit view-mode and return to previous buffer."
+  ;; In the following documentation string we have to use some explicit key
+  ;; bindings instead of using the \\[] construction. The reason for this
+  ;; is that most commands have more than one key binding.
+  "Toggle View mode, a minor mode for viewing text but not editing it.
+With arg, turn View mode on iff arg is positive.
+
+Emacs commands that do not change the buffer contents are available as usual.
+Kill commands insert text in kill buffers but do not delete. Other commands
+\(among them most letters and punctuation) beep and tell that the buffer is
+read-only.
+\\<view-mode-map>
+The following additional commands are provided.  Most commands take prefix
+arguments.  Page commands default to \"page size\" lines which is almost a whole
+window full, or number of lines set by \\[View-scroll-page-forward-set-page-size] or \\[View-scroll-page-backward-set-page-size].  Half page commands default to
+and set \"half page size\" lines which initially is half a window full.  Search
+commands default to a repeat count of one.
+
+H, h, ?	 This message.
+Digits	provide prefix arguments.
+\\[negative-argument]	negative prefix argument.
+\\[beginning-of-buffer]	move to the beginning of buffer.
+>	move to the end of buffer.
+\\[View-scroll-to-buffer-end]	scroll so that buffer end is at last line of window.
+SPC	scroll forward prefix (default \"page size\") lines.
+DEL	scroll backward prefix (default \"page size\") lines.
+\\[View-scroll-page-forward-set-page-size]	like  \\[View-scroll-page-forward]  except prefix sets \"page size\".
+\\[View-scroll-page-backward-set-page-size]	like  \\[View-scroll-page-backward]  except prefix sets \"page size\".
+\\[View-scroll-half-page-forward]	scroll forward (and if prefix set) \"half page size\" lines.
+\\[View-scroll-half-page-backward]	scroll backward (and if prefix set) \"half page size\" lines.
+RET, LFD  scroll forward prefix (default one) line(s).
+y	scroll backward prefix (default one) line(s).
+\\[View-revert-buffer-scroll-page-forward]	revert-buffer if necessary and scroll forward.
+	  Use this to view a changing file.
+\\[what-line]	prints the current line number.
+\\[View-goto-percent]	goes prefix argument (default 100) percent into buffer.
+\\[View-goto-line]	goes to line given by prefix argument (default first line).
+.	set the mark.
+x	exchanges point and mark.
+\\[View-back-to-mark]	return to mark and pops mark ring.
+	  Mark ring is pushed at start of every successful search and when
+	  jump to line occurs. The mark is set on jump to buffer start or end.
+\\[point-to-register]	save current position in character register.
+'	go to position saved in character register.
+s	do forward incremental search.
+r	do reverse incremental search.
+\\[View-search-regexp-forward]	searches forward for regular expression, starting after current page.
+	  ! and @ have a special meaning at the beginning of the regexp.
+	  ! means search for a line with no match for regexp. @ means start
+	  search at beginning (end for backward search) of buffer.
+\\	searches backward for regular expression, starting before current page.
+\\[View-search-last-regexp-forward]	searches forward for last regular expression.
+p	searches backward for last regular expression.
+\\[View-quit]	quit View mode, trying to restore window and buffer to previous state.
+	  \\[View-quit] is the normal way to leave view mode.
+\\[View-exit]	exit View mode but stay in current buffer. Use this if you started
+	  viewing a buffer (file) and find out you want to edit it.
+\\[View-exit-and-edit]	exit View mode and make the current buffer editable.
+\\[View-quit-all]	quit View mode, trying to restore windows and buffer to previous state.
+\\[View-leave]	quit View mode and maybe switch buffers, but don't kill this buffer.
+\\[View-kill-and-leave]	quit View mode, kill current buffer and go back to other buffer.
+
+The effect of \\[View-leave] , \\[View-quit] and \\[View-kill-and-leave] depends on how view-mode was entered. If it was
+entered by view-file, view-file-other-window or view-file-other-frame (\\[view-file],
+\\[view-file-other-window], \\[view-file-other-frame] or the dired mode v command), then \\[View-quit] will try to kill the
+current buffer. If view-mode was entered from another buffer as is done by
+View-buffer, View-buffer-other-window, View-buffer-other frame, View-file,
+View-file-other-window or View-file-other-frame then \\[view-leave] , \\[view-quit] and \\[view-kill-and-leave] will return
+to that buffer.
+
+Entry to view-mode runs the normal hook `view-mode-hook'."
   (interactive "P")
-  (setq view-mode
-	(if (null arg)
-	    (not view-mode)
-	  (> (prefix-numeric-value arg) 0)))
-  (force-mode-line-update))
-
-(defun view-mode-enter (&optional prev-buffer action)
-  "Enter View mode, a Minor mode for viewing text but not editing it.
-See the function `view-mode' for more details.
-
-This function runs the normal hook `view-mode-hook'.
-
-\\{view-mode-map}"
-;  Not interactive because dangerous things happen
-;  if you call it without passing a buffer as argument
-;  and they are not easy to fix.
-;  (interactive)
-  (setq view-old-buffer-read-only buffer-read-only)
-  (setq view-old-Helper-return-blurb
-	(and (boundp 'Helper-return-blurb) Helper-return-blurb))
-
-  ;; Enable view-exit to make use of the data we just saved
-  ;; and to perform the exit action.
-  (setq view-mode-auto-exit t)
-
-  (setq buffer-read-only t)
-  (setq view-mode t)
-  (setq Helper-return-blurb
-	(format "continue viewing %s"
-		(if (buffer-file-name)
-		    (file-name-nondirectory (buffer-file-name))
-		    (buffer-name))))
-
-  (setq view-exit-action action)
-  (setq view-return-here prev-buffer)
-  (setq view-exit-position (point-marker))
-
-  (beginning-of-line)
-  (setq goal-column nil)
-
-  (run-hooks 'view-mode-hook)
-  (message "%s"
-     (substitute-command-keys
-      "Type \\[help-command] for help, \\[describe-mode] for commands, \\[view-exit] to quit.")))
-
-(defun view-exit ()
-  "Exit from view-mode.
-If you viewed an existing buffer, that buffer returns to its previous mode.
-If you viewed a file that was not present in Emacs, its buffer is killed."
+  (cond
+   ((and arg
+	 (if (> (prefix-numeric-value arg) 0) view-mode (not view-mode)))
+    ())					; Do nothing if already OK.
+   (view-mode (view-mode-exit))
+   (t (view-mode-enter))))
+
+;;;###autoload
+(defun view-mode-enter (&optional return-to exit-action) "\
+Enter View mode and set up exit from view mode depending on optional arguments.
+If RETURN-TO is non-nil it is added as an element to the buffer local alist
+view-return-to-alist.
+Save EXIT-ACTION in buffer local variable view-exit-action.
+RETURN-TO is either nil, meaning do nothing when exiting view mode, or
+\(<window> <old-window> . <old-buf-info>).
+<window> is a window used for viewing.
+<old-window> is nil or the window to select after viewing.
+<old-buf-info> tells what to do with <window> when exiting. It is one of:
+1) nil       Do nothing.
+2) t         Delete <window> or, if it is the only window, its frame.
+3) (<old-buff> <start> <point>)  Display buffer <old-buff> with displayed text
+                          starting at <start> and point at <point> in <window>.
+EXIT-ACTION is either nil or a function with buffer as argument. This function
+is called by view-mode-exit.
+
+See the function `view-mode' for details of view mode.
+
+This function runs the normal hook `view-mode-hook'."
+  (if return-to
+      (let ((entry (assq (car return-to) view-return-to-alist)))
+	(if entry (setcdr entry (cdr return-to))
+	  (setq view-return-to-alist (cons return-to view-return-to-alist)))))
+  (if view-mode ()			; Do nothing if already in view mode.
+    (setq view-mode t
+	  view-page-size (view-page-size-default view-page-size)
+	  view-half-page-size (or view-half-page-size (/ (view-window-size) 2))
+	  view-old-buffer-read-only buffer-read-only
+	  buffer-read-only t
+	  view-old-Helper-return-blurb (and (boundp 'Helper-return-blurb)
+					    Helper-return-blurb)
+	  Helper-return-blurb
+	  (format "continue viewing %s"
+		  (if (buffer-file-name)
+		      (file-name-nondirectory (buffer-file-name))
+		    (buffer-name)))
+	  view-exit-action exit-action)
+    (run-hooks 'view-mode-hook)
+    (force-mode-line-update)
+    (message "%s"
+	     (substitute-command-keys "\
+Type \\[help-command] for help, \\[describe-mode] for commands, \\[View-quit] to quit."))))
+
+(defun view-mode-exit (&optional return-to-alist exit-action all-win)
+  "Exit view-mode in various ways, depending on optional arguments.
+RETURN-TO-ALIST, EXIT-ACTION and ALL-WIN determine what to do after
+exit.
+EXIT-ACTION is nil or a function that is called with current buffer as
+argument.
+RETURN-TO-ALIST is an alist that for some of the windows displaying the current
+buffer, associate information on what to do with those windows. If ALL-WIN is
+non-nil, then all windows on RETURN-TO-ALIST are restored to their old state.
+If ALL-WIN is nil, then only the selected window is affected (if it is on
+ALL-WIN). Each element has the format (<window> <old-window> . <old-buf-info>)
+where <window> is a window displaying the current buffer and <old-buf-info> is
+information on what to do with <window>. <old-buf-info> is one of:
+1) nil       Do nothing.
+2) t         Delete <window> or, if it is the only window, its frame.
+3) (<old-buf> <start> <point>)  Display buffer <old-buf> with displayed text
+                          starting at <start> and point at <point> in <window>.
+If one of the <window> in RETURN-TO-ALIST is the selected window and the
+corresponding <old-window> is a live window, then select <old-window>."
+  (if view-mode		; Only do something if in view mode.
+      (let* ((buffer (current-buffer))
+	     window
+	     (sel-old (assq (selected-window) return-to-alist))
+	     (old-window (or (and sel-old (car (cdr sel-old)))
+			     (and all-win (selected-window))))
+	     (alist (if (setq all-win
+			      (or all-win view-exit-all-windows-at-exit))
+			return-to-alist	; Try to restore all windows.
+		      (and sel-old (list sel-old))))) ; Only selected window.
+	(and view-overlay (delete-overlay view-overlay))
+	(setq view-mode nil
+	      view-exit-action nil
+	      view-return-to-alist nil
+	      Helper-return-blurb view-old-Helper-return-blurb
+	      buffer-read-only view-old-buffer-read-only)
+	(while alist			; Restore windows with info.
+	  (if (and (window-live-p (setq window (car (car alist))))
+		   (eq buffer (window-buffer window)))
+	      (let ((frame (window-frame window))
+		    (old-buf-info (cdr (cdr (car alist)))))
+		(if all-win (select-window window))
+		(cond
+		 ((and (consp old-buf-info) ; Case 3.
+		       (buffer-live-p (car old-buf-info)))
+		  (set-window-buffer window (car old-buf-info)) ; old-buf
+		  (set-window-start window (car (cdr old-buf-info)))
+		  (set-window-point window (car (cdr (cdr old-buf-info)))))
+		 ((not (eq old-buf-info t)) nil) ; Not case 2, do nothing.
+		 ((not (one-window-p t)) (delete-window))
+		 ((not (eq frame (next-frame))) ; Not the only frame, so
+		  (if view-remove-frame-by-deleting (delete-frame frame)
+		    (iconify-frame frame)))))) ; can safely be removed.
+	  (setq alist (cdr alist)))
+	(if (and return-to-alist view-exit-all-windows-at-exit)
+	    (replace-buffer-in-windows buffer))
+	(if (window-live-p old-window)	; still existing window
+	    (select-window old-window))
+	(if (and exit-action (not (get-buffer-window buffer)))
+	    (funcall exit-action buffer))
+	(force-mode-line-update))))
+
+(defun View-exit ()
+  "Exit View mode but stay in current buffer."
   (interactive)
-  (setq view-mode nil)
-  (and view-overlay (delete-overlay view-overlay))
-  (force-mode-line-update)
-  (cond (view-mode-auto-exit
-	 (setq buffer-read-only view-old-buffer-read-only)
-	 (setq view-mode-auto-exit nil)
-
-	 (goto-char view-exit-position)
-	 (set-marker view-exit-position nil)
-
-	 ;; Now do something to the buffer that we were viewing
-	 ;; (such as kill it).
-	 (let ((viewed-buffer (current-buffer))
-	       (action view-exit-action))
-	   (cond
-	    ((bufferp view-return-here)
-	     (switch-to-buffer view-return-here))
-	    ((window-configuration-p view-return-here)
-	     (set-window-configuration view-return-here)))
-	   (if action (funcall action viewed-buffer))))))
-
-(defun view-window-size () (1- (window-height)))
-
-(defun view-scroll-size ()
-  (min (view-window-size) (or view-scroll-size (view-window-size))))
+  (view-mode-exit))
 
-(defvar view-mode-hook nil
-  "Normal hook run when starting to view a buffer or file.")
+(defun View-exit-and-edit ()
+  "Exit View mode and make the current buffer editable."
+  (interactive)
+  (view-mode-exit)
+  (setq buffer-read-only nil))
+
+(defun View-leave ()
+  "Quit View mode and maybe switch buffers, but don't kill this buffer."
+  (interactive)
+  (view-mode-exit view-return-to-alist))
+
+(defun View-quit ()
+  "Quit View mode, trying to restore window and buffer to previous state.
+Maybe kill current buffer. Try to restore selected window to previous state
+and go to previous buffer or window."
+  (interactive)
+  (view-mode-exit view-return-to-alist view-exit-action))
+
+(defun View-quit-all ()
+  "Quit View mode, trying to restore all windows and buffer to previous state.
+Maybe kill current buffer. Try to restore all windows viewing buffer to
+previous state and go to previous buffer or window."
+  (interactive)
+  (view-mode-exit view-return-to-alist view-exit-action t))
+
+(defun View-kill-and-leave ()
+  "Quit View mode, kill current buffer and return to previous buffer."
+  (interactive)
+  (view-mode-exit view-return-to-alist (or view-exit-action 'kill-buffer) t))
+
+
+;;; Some help routines.
+
+(defun view-window-size ()
+  ;; Window height excluding mode line.
+  (1- (window-height)))
 
 ;(defun view-last-command (&optional who what)
 ;  (setq view-last-command-entry this-command)
@@ -321,133 +558,287 @@ If you viewed a file that was not present in Emacs, its buffer is killed."
 ;      (funcall view-last-command view-last-command-argument))
 ;  (setq this-command view-last-command-entry))
 
-(defun View-goto-line (line)
-  "Move to line LINE in View mode.
-Display is centered at LINE.  Sets mark at starting position and pushes
-mark ring."
+(defun view-recenter ()
+  ;; Center point in window.
+  (recenter (/ (view-window-size) 2)))
+
+(defun view-page-size-default (lines)
+  ;; Get page size.
+  (let ((default (- (view-window-size) next-screen-context-lines)))
+    (if (or (null lines) (zerop (setq lines (prefix-numeric-value lines))))
+	default
+      (min (abs lines) default))))
+
+(defun view-set-half-page-size-default (lines)
+  ;; Get and maybe set half page size.
+  (if (not lines) view-half-page-size
+    (setq view-half-page-size
+	  (if (zerop (setq lines (prefix-numeric-value lines)))
+	      (/ (view-window-size) 2)
+	    (view-page-size-default lines)))))
+
+
+;;; Commands for moving around in the buffer.
+
+(defun View-goto-percent (&optional percent)
+  "Move to end (or prefix PERCENT) of buffer in View mode.
+Display is centered at point.
+Sets mark at starting position and pushes mark ring."
+  (interactive "P")
+  (push-mark)
+  (goto-char
+   (if percent
+       (+ (point-min)
+	  (floor (* (- (point-max) (point-min)) 0.01
+		    (max 0 (min 100 (prefix-numeric-value percent))))))
+     (point-max)))
+  (view-recenter))
+
+;(defun View-goto-line-last (&optional line)
+;"Move to last (or prefix LINE) line in View mode.
+;Display is centered at LINE.
+;Sets mark at starting position and pushes mark ring."
+;  (interactive "P")
+;  (push-mark)
+;  (if line (goto-line (prefix-numeric-value line))
+;    (goto-char (point-max))
+;    (beginning-of-line))
+;  (view-recenter))
+  
+(defun View-goto-line (&optional line)
+  "Move to first (or prefix LINE) line in View mode.
+Display is centered at LINE.
+Sets mark at starting position and pushes mark ring."
   (interactive "p")
   (push-mark)
   (goto-line line)
-  (recenter (/ (view-window-size) 2)))
+  (view-recenter))
 
-(defun View-scroll-lines-forward (&optional lines)
-  "Scroll forward in View mode, or exit if end of text is visible.
-No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
-Arg is number of lines to scroll."
+(defun View-scroll-to-buffer-end ()
+  "Scroll backward or forward so that buffer end is at last line of window."
+  (interactive)
+  (let ((p (if (pos-visible-in-window-p (point-max)) (point))))
+    (goto-char (point-max))
+    (recenter -1)
+    (and p (goto-char p))))
+
+(defun view-scroll-lines (lines backward default maxdefault)
+  ;; This function does the job for all the scrolling commands.
+  ;; Scroll forward LINES lines. If BACKWARD is true scroll backwards.
+  ;; If LINES is negative scroll in the other direction. If LINES is 0 or nil,
+  ;; scroll DEFAULT lines. If MAXDEFAULT is true then scroll no more than a
+  ;; window full.
+  (if (or (null lines) (zerop (setq lines (prefix-numeric-value lines))))
+      (setq lines default))
+  (if (< lines 0)
+      (progn (setq backward (not backward)) (setq lines (- lines))))
+  (setq default (view-page-size-default nil)) ; Max scrolled at a time.
+  (if maxdefault (setq lines (min lines default)))
+  (cond
+   (backward (scroll-down lines))
+   ((view-really-at-end)
+    (if view-scroll-auto-exit (View-quit)
+      (ding)
+      (view-end-message)))
+   (t (while (> lines default)
+	(scroll-up default)
+	(setq lines (- lines default))
+	(if (view-really-at-end) (setq lines 0)))
+      (scroll-up lines)
+      (if (view-really-at-end) (view-end-message))
+      (move-to-window-line -1)
+      (beginning-of-line))))
+
+(defun view-really-at-end ()
+  ;; Return true if buffer end visible. Maybe revert buffer and test.
+  (and (pos-visible-in-window-p (point-max))
+       (let ((buf (current-buffer))
+	     (bufname (buffer-name))
+	     (file (buffer-file-name)))
+	 (or (not view-try-extend-at-buffer-end)
+	     (not file)
+	     (verify-visited-file-modtime buf)
+	     (not (file-exists-p file))
+	     (and (buffer-modified-p buf)
+		  (setq file (file-name-nondirectory file))
+		  (not (yes-or-no-p
+			(format
+			 "File %s changed on disk.  Discard your edits%s? "
+			 file
+			 (if (string= bufname file) ""
+			   (concat " in " bufname))))))
+	     (progn (revert-buffer t t t)
+		    (pos-visible-in-window-p (point-max)))))))
+
+(defun view-end-message ()
+  ;; Tell that we are at end of buffer.
+  (goto-char (point-max))
+  (message "End of buffer.  Type %s to quit viewing."
+	   (substitute-command-keys
+	    (if view-scroll-auto-exit "\\[View-scroll-page-forward]"
+	      "\\[View-quit]"))))
+
+(defun View-scroll-page-forward (&optional lines)
+  "Scroll \"page size\" or prefix LINES lines forward in View mode.
+This will exit if end of text is visible and view-scroll-auto-exit is non-nil.
+\"page size\" is whole window full, or number of lines set by
+\\[View-scroll-page-forward-set-page-size] or
+\\[View-scroll-page-backward-set-page-size].
+If LINES is more than a window-full, only the last window-full is shown."
   (interactive "P")
-  (setq lines
-	(if lines (prefix-numeric-value lines)
-	  (view-scroll-size)))
-  (if (and (pos-visible-in-window-p (point-max))
-	   ;; Allow scrolling backward at the end of the buffer.
-	   (> lines 0)
-	   view-mode-auto-exit)
-      (view-exit)
-    ;; (view-last-command 'View-scroll-lines-forward lines)
-    (if (>= lines (view-window-size))
-	(scroll-up nil)
-      (if (>= (- lines) (view-window-size))
-	  (scroll-down nil)
-	(scroll-up lines)))
-    (cond ((pos-visible-in-window-p (point-max))
-	   (goto-char (point-max))
-	   (message "%s"
-		    (substitute-command-keys
-		     "End.  Type \\[view-exit] to quit viewing."))))
-    (move-to-window-line -1)
-    (beginning-of-line)))
-
-(defun View-scroll-lines-forward-set-scroll-size (&optional lines)
-  "Scroll forward LINES lines in View mode, setting the \"scroll size\".
-This is the number of lines which \\[View-scroll-lines-forward] and \\[View-scroll-lines-backward] scroll by default.
-The absolute value of LINES is used, so this command can be used to scroll
-backwards (but \"scroll size\" is always positive).  If LINES is greater than
-window height or omitted, then window height is assumed.  If LINES is less
-than window height then scrolling context is provided from previous screen."
+  (view-scroll-lines lines nil view-page-size nil))
+
+(defun View-scroll-page-backward (&optional lines) 
+  "Scroll \"page size\" or prefix LINES lines backward in View mode.
+See further View-scroll-page-forward."
   (interactive "P")
-  (if (not lines)
-      (setq view-scroll-size (view-window-size))
-    (setq lines (prefix-numeric-value lines))
-    (setq view-scroll-size
-	  (min (if (> lines 0) lines (- lines)) (view-window-size))))
-  (View-scroll-lines-forward lines))
-
-(defun View-scroll-one-more-line (&optional arg)
-  "Scroll one more line up in View mode.
-With ARG scroll one line down."
+  (view-scroll-lines lines t view-page-size nil))
+  
+(defun View-scroll-page-forward-set-page-size (&optional lines)
+  "Scroll forward prefix LINES lines in View mode, setting the \"page size\".
+This is the number of lines which \\[View-scroll-page-forward] and
+\\[View-scroll-page-backward] scroll by default. If LINES is omitted or = 0,
+sets \"page size\" to window height and scrolls forward that much, otherwise
+scrolls forward LINES lines and sets \"page size\" to the minimum of window
+height and the absolute value of LINES.
+See further View-scroll-page-forward."
   (interactive "P")
-  (View-scroll-lines-forward (if (not arg) 1 -1)))
+  (view-scroll-lines lines nil
+		     (setq view-page-size (view-page-size-default lines))
+		     nil))
 
-(defun View-scroll-lines-backward (&optional lines)
-  "Scroll backward in View mode.
-No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
-Arg is number of lines to scroll."
+(defun View-scroll-page-backward-set-page-size (&optional lines)
+  "Scroll backward prefix LINES lines in View mode, setting the \"page size\".
+See further View-scroll-page-forward-set-page-size."
   (interactive "P")
-  (View-scroll-lines-forward (if lines
-				 (- (prefix-numeric-value lines))
-			       (- (view-scroll-size)))))
-  
+  (view-scroll-lines lines t
+		     (setq view-page-size (view-page-size-default lines))
+		     nil))
+
+(defun View-scroll-line-forward (&optional lines)
+  "Scroll forward one line (or prefix LINES lines) in View mode.
+See further View-scroll-page-forward, but note that scrolling is limited
+to minimum of LINES and one window-full."
+  (interactive "P")
+  (view-scroll-lines lines nil 1 t))
+
+(defun View-scroll-line-backward (&optional lines)
+  "Scroll backward one line (or prefix LINES lines) in View mode.
+See further View-scroll-line-forward."
+  (interactive "P")
+  (view-scroll-lines lines t 1 t))
+
+(defun View-scroll-half-page-forward (&optional lines)
+  "Scroll forward \"half page size\" (or prefix LINES) lines in View mode.
+If LINES is not omitted, the \"half page size\" is set to the minimum of
+window height and the absolute value of LINES.
+LINES=0 resets \"half page size\" to half window height."
+  (interactive "P")
+  (view-scroll-lines lines nil (view-set-half-page-size-default lines) t))
+
+(defun View-scroll-half-page-backward (&optional lines)
+  "Scroll backward \"half page size\" (or prefix LINES) lines in View mode.
+See further View-scroll-half-page-forward."
+  (interactive "P")
+  (view-scroll-lines lines t (view-set-half-page-size-default lines) t))
+
+(defun View-revert-buffer-scroll-page-forward (&optional lines)  "\
+Scroll \"page size\" or prefix LINES lines forward reverting buffer if needed.
+If buffer has not been changed and the corresponding file is newer, first
+revert the buffer, then scroll.
+This command is useful if you are viewing a changing file.
+\"page size\" is whole window full, or number of lines set by
+\\[View-scroll-page-forward-set-page-size] or
+\\[View-scroll-page-backward-set-page-size].
+If LINES is more than a window-full, only the last window-full is shown."
+  (interactive "P")
+  (let ((view-mode-auto-exit nil)
+	(view-try-extend-at-buffer-end t))
+    (view-scroll-lines lines nil view-page-size nil)))
+
+(defun View-back-to-mark (&optional ignore)
+  "Return to last mark set in View mode, else beginning of file.
+Displays line at center of window.  Pops mark ring so successive
+invocations return to earlier marks."
+  (interactive)
+  (goto-char (or (mark t) (point-min)))
+  (pop-mark)
+  (view-recenter))
+	     
 (defun View-search-regexp-forward (n regexp)
-  "Search forward for Nth occurrence of REGEXP.
-Displays line found at center of window.  REGEXP is remembered for
-searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring.
+  "Search forward for first (or prefix Nth) occurrence of REGEXP in View mode.
+Displays line found at center of window.  REGEXP is remembered for searching
+with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward]. Sets mark at starting position and pushes mark ring.
+Characters @ or ! or combined as @! or !@ are special if entered at the
+beginning of REGEXP. They modify the search rather than become part of pattern
+searched for. @ means start search at the beginning of buffer. ! means search
+for line that not contains match for pattern. If REGEXP only consist of these
+control characters, then an earlier remembered REGEXP is used.
 
 The variable `view-highlight-face' controls the face that is used
 for highlighting the match that is found."
-  (interactive "p\nsSearch forward (regexp): ")
-;;;(view-last-command 'View-search-last-regexp-forward n)
-  (view-search n (if (equal regexp "") view-last-regexp regexp)))
+  (interactive "p\nsSearch forward (regexp): ") 
+  (view-search n regexp))
 
 (defun View-search-regexp-backward (n regexp)
-  "Search backward from window start for Nth instance of REGEXP.
-Displays line found at center of window.  REGEXP is remembered for
-searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring.
+  "Search backward for first (or prefix Nth) occurrence of REGEXP in View mode.
+Displays line found at center of window.  REGEXP is remembered for searching
+with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward]. Sets mark at starting position and pushes mark ring.
+Characters @ or ! or combined as @! or !@ are special if entered at the
+beginning of REGEXP. They modify the search rather than become part of pattern
+searched for. @ means start search at the end of buffer. ! means search
+for line that not contains match for pattern. If REGEXP only consist of these
+control characters, then an earlier remembered REGEXP is used.
 
 The variable `view-highlight-face' controls the face that is used
 for highlighting the match that is found."
   (interactive "p\nsSearch backward (regexp): ")
-  (View-search-regexp-forward (- n)
-			      (if (equal regexp "") view-last-regexp regexp)))
+  (view-search (- n) regexp))
 
-(defun View-search-last-regexp-forward (n)
-  "Search forward from window end for Nth instance of last regexp.
-Displays line found at center of window.  Sets mark at starting position
-and pushes mark ring.
+(defun View-search-last-regexp-forward (n) "\
+Search forward for first (or prefix Nth) instance of last regexp in View mode.
+Displays line found at center of window.  Sets mark at starting position and
+pushes mark ring.
 
 The variable `view-highlight-face' controls the face that is used
 for highlighting the match that is found."
   (interactive "p")
-  (if view-last-regexp
-      (View-search-regexp-forward n view-last-regexp)
-    (error "No previous View-mode search")))
+  (view-search n nil))
 
-(defun View-search-last-regexp-backward (n)
-  "Search backward from window start for Nth instance of last regexp.
+(defun View-search-last-regexp-backward (n) "\
+Search backward for first (or prefix Nth) instance of last regexp in View mode.
 Displays line found at center of window.  Sets mark at starting position and
 pushes mark ring.
 
 The variable `view-highlight-face' controls the face that is used
 for highlighting the match that is found."
   (interactive "p")
-  (if view-last-regexp
-      (View-search-regexp-backward n view-last-regexp)
-    (error "No previous View-mode search")))
+  (view-search (- n) nil))
 
-(defun View-back-to-mark (&optional ignore)
-  "Return to last mark set in View mode, else beginning of file.
-Displays line at center of window.  Pops mark ring so successive
-invocations return to earlier marks."
-  (interactive)
-  (goto-char (or (mark t) (point-min)))
-  (pop-mark)
-  (recenter (/ (view-window-size) 2)))
-	     
 (defun view-search (times regexp)
-  (setq view-last-regexp regexp)
-  (let (where)
+  ;; This function does the job for all the view-search commands.
+  (let (where no end ln)
+    (cond
+     ((and regexp (> (length regexp) 0)
+	   (or (not (memq (string-to-char regexp) '(?! ?@)))
+	       (progn
+		 (if (member (substring regexp 0 2) '("!@" "@!"))
+		     (setq end t no t ln 2)
+		   (setq no (not (setq end (eq ?@ (string-to-char regexp))))
+			 ln 1))
+		 (> (length (setq regexp (substring regexp ln))) 0))))
+      (setq view-last-regexp (if no (list regexp) regexp)))
+     ((consp view-last-regexp)
+      (setq regexp (car view-last-regexp))
+      (if (not (setq no (not no))) (setq view-last-regexp regexp)))
+     (view-last-regexp (setq regexp view-last-regexp)
+		       (if no (setq view-last-regexp (list regexp))))
+     (t (error "No previous View-mode search")))
     (save-excursion
-      (move-to-window-line (if (< times 0) 0 -1))
-      (if (re-search-forward regexp nil t times)
+      (if end (goto-char (if (< times 0) (point-max) (point-min)))
+	(move-to-window-line (if (< times 0) 0 -1)))
+      (if (if no (view-search-no-match-lines times regexp)
+	    (re-search-forward regexp nil t times))
 	  (setq where (point))))
     (if where
 	(progn
@@ -459,11 +850,33 @@ invocations return to earlier marks."
 		  (make-overlay (match-beginning 0) (match-end 0))))
 	  (overlay-put view-overlay 'face view-highlight-face)
 	  (beginning-of-line)
-	  (recenter (/ (view-window-size) 2)))
-      (message "Can't find occurrence %d of %s" times regexp)
+	  (view-recenter))
+      (message "Can't find occurrence %d of %s%s"
+	       times (if no "no " "") regexp)
       (sit-for 4))))
 
-
+(defun view-search-no-match-lines (times regexp)
+  ;; Search for the TIMESt occurrence of line with no match for REGEXP.
+  (let ((back (and (< times 0) (setq times (- times)) -1))
+	n)
+    (while (> times 0)
+      (save-excursion (beginning-of-line (if back (- times) (1+ times)))
+		      (setq n (point)))
+      (setq times
+	    (cond
+	     ((< (count-lines (point) n) times) -1) ; Not enough lines.
+	     ((or (null (re-search-forward regexp nil t back))
+		  (if back (and (< (match-end 0) n)
+				(> (count-lines (match-end 0) n) 1))
+		    (and (< n (match-beginning 0))
+			 (> (count-lines n (match-beginning 0)) 1))))
+	      0)			; No match within lines.
+	     (back (count-lines (max n (match-beginning 0)) (match-end 0)))
+	     (t (count-lines (match-beginning 0) (min n (match-end 0))))))
+      (goto-char n))
+    (and (zerop times) (looking-at "^.*$"))))
+
+
 (provide 'view)
 
 ;;; view.el ends here