;;; simple.el --- basic editing commands for XEmacs

;; Copyright (C) 1985, 1986, 1987, 1993-1995 Free Software Foundation, Inc.
;; Copyright (C) 1995 Tinker Systems and INS Engineering Corp.

;; This file is part of XEmacs.

;; XEmacs is free software; you can redistribute it and/or modify it
;; under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; XEmacs is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with XEmacs; see the file COPYING.  If not, write to the Free
;; Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Synched up with: FSF 19.30.

;;; Commentary:

;; A grab-bag of basic XEmacs commands not specifically related to some
;; major mode or to file-handling.

;;; Changes for zmacs-style active-regions:
;;;
;;; beginning-of-buffer, end-of-buffer, count-lines-region, 
;;; count-lines-buffer, what-line, what-cursor-position, set-goal-column,
;;; set-fill-column, prefix-arg-internal, and line-move (which is used by
;;; next-line and previous-line) set zmacs-region-stays to t, so that they
;;; don't affect the current region-hilighting state.
;;;
;;; mark-whole-buffer, mark-word, exchange-point-and-mark, and
;;; set-mark-command (without an argument) call zmacs-activate-region.
;;;
;;; mark takes an optional arg like the new Fmark_marker() does.  When 
;;; the region is not active, mark returns nil unless the optional arg is true.
;;;
;;; push-mark, pop-mark, exchange-point-and-mark, and set-marker, and
;;; set-mark-command use (mark t) so that they can access the mark whether
;;; the region is active or not.  
;;;
;;; shell-command, shell-command-on-region, yank, and yank-pop (which all
;;; push a mark) have been altered to call exchange-point-and-mark with an
;;; argument, meaning "don't activate the region".  These commands  only use
;;; exchange-point-and-mark to position the newly-pushed mark correctly, so
;;; this isn't a user-visible change.  These functions have also been altered
;;; to use (mark t) for the same reason.

;;; Code:

(defun newline (&optional arg)
  "Insert a newline, and move to left margin of the new line if it's blank.
The newline is marked with the text-property `hard'.
With arg, insert that many newlines.
In Auto Fill mode, if no numeric arg, break the preceding line if it's long."
  (interactive "*P")
  (barf-if-buffer-read-only nil (point))
  ;; Inserting a newline at the end of a line produces better redisplay in
  ;; try_window_id than inserting at the beginning of a line, and the textual
  ;; result is the same.  So, if we're at beginning of line, pretend to be at
  ;; the end of the previous line.
  (let ((flag (and (not (bobp)) 
		   (bolp)
		   (< (or (previous-extent-change (point)) -2) 
		      (- (point) 2))))
	(was-page-start (and (bolp)
			     (looking-at page-delimiter)))
	(beforepos (point)))
    (if flag (backward-char 1))
    ;; Call self-insert so that auto-fill, abbrev expansion etc. happens.
    ;; Set last-command-char to tell self-insert what to insert.
    (let ((last-command-char ?\n)
	  ;; Don't auto-fill if we have a numeric argument.
	  ;; Also not if flag is true (it would fill wrong line);
	  ;; there is no need to since we're at BOL.
	  (auto-fill-function (if (or arg flag) nil auto-fill-function)))
      (unwind-protect
	  (self-insert-command (prefix-numeric-value arg))
	;; If we get an error in self-insert-command, put point at right place.
	(if flag (forward-char 1))))
    ;; If we did *not* get an error, cancel that forward-char.
    (if flag (backward-char 1))
    ;; Mark the newline(s) `hard'.
    (if use-hard-newlines
	(let* ((from (- (point) (if arg (prefix-numeric-value arg) 1)))
	       (sticky (get-text-property from 'end-open)))
	  (put-text-property from (point) 'hard 't)
	  ;; If end-open is not "t", add 'hard to end-open list
	  (if (and (listp sticky) (not (memq 'hard sticky)))
	      (put-text-property from (point) 'end-open
				 (cons 'hard sticky)))))
    ;; If the newline leaves the previous line blank,
    ;; and we have a left margin, delete that from the blank line.
    (or flag
	(save-excursion
	  (goto-char beforepos)
	  (beginning-of-line)
	  (and (looking-at "[ \t]$")
	       (> (current-left-margin) 0)
	       (delete-region (point) (progn (end-of-line) (point))))))
    (if flag (forward-char 1))
    ;; Indent the line after the newline, except in one case:
    ;; when we added the newline at the beginning of a line
    ;; which starts a page.
    (or was-page-start
	(move-to-left-margin nil t)))
  nil)

(defun open-line (arg)
  "Insert a newline and leave point before it.
If there is a fill prefix and/or a left-margin, insert them on the new line
if the line would have been blank.
With arg N, insert N newlines."
;;   "Insert a newline and leave point before it.
;; If there is a fill prefix, insert the fill prefix on the new line
;; if the line would have been empty.
;; With arg N, insert N newlines."
  (interactive "*p")
  (let* ((do-fill-prefix (and fill-prefix (bolp)))
	 ;well, I'm going to re-enable this.  --ben
	 ;(do-fill-prefix nil)  ;; screw this -- says JWZ
	 (do-left-margin (and (bolp) (> (current-left-margin) 0)))
	 (loc (point)))
    (newline arg)
    (goto-char loc)
    (while (> arg 0)
      (cond ((bolp)
	     (if do-left-margin (indent-to (current-left-margin)))
	     (if do-fill-prefix (insert fill-prefix))))
      (forward-line 1)
      (setq arg (1- arg)))
    (goto-char loc)
    (end-of-line)))

(defun split-line ()
  "Split current line, moving portion beyond point vertically down."
  (interactive "*")
  (skip-chars-forward " \t")
  (let ((col (current-column))
	(pos (point)))
    (newline 1)
    (indent-to col 0)
    (goto-char pos)))

(defun quoted-insert (arg)
  "Read next input character and insert it.
This is useful for inserting control characters.
You may also type up to 3 octal digits, to insert a character with that code.

In overwrite mode, this function inserts the character anyway, and
does not handle octal digits specially.  This means that if you use
overwrite as your normal editing mode, you can use this function to
insert characters when necessary.

In binary overwrite mode, this function does overwrite, and octal
digits are interpreted as a character code.  This is supposed to make
this function useful in editing binary files."
  (interactive "*p")
  (let ((char (if (or (not overwrite-mode)
		      (eq overwrite-mode 'overwrite-mode-binary))
		  (read-quoted-char)
		(read-char))))
    (if (> arg 0)
	(if (eq overwrite-mode 'overwrite-mode-binary)
	    (delete-char arg)))
    (while (> arg 0)
      (insert char)
      (setq arg (1- arg)))))

(defun delete-indentation (&optional arg)
  "Join this line to previous and fix up whitespace at join.
If there is a fill prefix, delete it from the beginning of this line.
With argument, join this line to following line."
  (interactive "*P")
  (beginning-of-line)
  (if arg (forward-line 1))
  (if (eq (preceding-char) ?\n)
      (progn
	(delete-region (point) (1- (point)))
	;; If the second line started with the fill prefix,
	;; delete the prefix.
	(if (and fill-prefix
		 (<= (+ (point) (length fill-prefix)) (point-max))
		 (string= fill-prefix
			  (buffer-substring (point)
					    (+ (point) (length fill-prefix)))))
	    (delete-region (point) (+ (point) (length fill-prefix))))
	(fixup-whitespace))))

(defun fixup-whitespace ()
  "Fixup white space between objects around point.
Leave one space or none, according to the context."
  (interactive "*")
  (save-excursion
    (delete-horizontal-space)
    (if (or (looking-at "^\\|\\s)")
	    (save-excursion (forward-char -1)
			    (looking-at "$\\|\\s(\\|\\s'")))
	nil
      (insert ?\ ))))

(defun delete-horizontal-space ()
  "Delete all spaces and tabs around point."
  (interactive "*")
  (skip-chars-backward " \t")
  (delete-region (point) (progn (skip-chars-forward " \t") (point))))

(defun just-one-space ()
  "Delete all spaces and tabs around point, leaving one space."
  (interactive "*")
  (expand-abbrev)
  (skip-chars-backward " \t")
  (if (= (following-char) ? )
      (forward-char 1)
    (insert ? ))
  (delete-region (point) (progn (skip-chars-forward " \t") (point))))

(defun delete-blank-lines ()
  "On blank line, delete all surrounding blank lines, leaving just one.
On isolated blank line, delete that one.
On nonblank line, delete any immediately following blank lines."
  (interactive "*")
  (let (thisblank singleblank)
    (save-excursion
      (beginning-of-line)
      (setq thisblank (looking-at "[ \t]*$"))
      ;; Set singleblank if there is just one blank line here.
      (setq singleblank
	    (and thisblank
		 (not (looking-at "[ \t]*\n[ \t]*$"))
		 (or (bobp)
		     (progn (forward-line -1)
			    (not (looking-at "[ \t]*$")))))))
    ;; Delete preceding blank lines, and this one too if it's the only one.
    (if thisblank
	(progn
	  (beginning-of-line)
	  (if singleblank (forward-line 1))
	  (delete-region (point)
			 (if (re-search-backward "[^ \t\n]" nil t)
			     (progn (forward-line 1) (point))
			   (point-min)))))
    ;; Delete following blank lines, unless the current line is blank
    ;; and there are no following blank lines.
    (if (not (and thisblank singleblank))
	(save-excursion
	  (end-of-line)
	  (forward-line 1)
	  (delete-region (point)
			 (if (re-search-forward "[^ \t\n]" nil t)
			     (progn (beginning-of-line) (point))
			   (point-max)))))
    ;; Handle the special case where point is followed by newline and eob.
    ;; Delete the line, leaving point at eob.
    (if (looking-at "^[ \t]*\n\\'")
	(delete-region (point) (point-max)))))

(defun back-to-indentation ()
  "Move point to the first non-whitespace character on this line."
  (interactive "_")
  (beginning-of-line 1)
  (skip-chars-forward " \t"))

(defun newline-and-indent ()
  "Insert a newline, then indent according to major mode.
Indentation is done using the value of `indent-line-function'.
In programming language modes, this is the same as TAB.
In some text modes, where TAB inserts a tab, this command indents to the
column specified by the function `current-left-margin'."
  (interactive "*")
  (delete-region (point) (progn (skip-chars-backward " \t") (point)))
  (newline)
  (indent-according-to-mode))

(defun reindent-then-newline-and-indent ()
  "Reindent current line, insert newline, then indent the new line.
Indentation of both lines is done according to the current major mode,
which means calling the current value of `indent-line-function'.
In programming language modes, this is the same as TAB.
In some text modes, where TAB inserts a tab, this indents to the
column specified by the function `current-left-margin'."
  (interactive "*")
  (save-excursion
    (delete-region (point) (progn (skip-chars-backward " \t") (point)))
    (indent-according-to-mode))
  (newline)
  (indent-according-to-mode))

;; Internal subroutine of delete-char
(defun kill-forward-chars (arg)
  (if (listp arg) (setq arg (car arg)))
  (if (eq arg '-) (setq arg -1))
  (kill-region (point) (+ (point) arg)))

;; Internal subroutine of backward-delete-char
(defun kill-backward-chars (arg)
  (if (listp arg) (setq arg (car arg)))
  (if (eq arg '-) (setq arg -1))
  (kill-region (point) (- (point) arg)))

(defun backward-delete-char-untabify (arg &optional killp)
  "Delete characters backward, changing tabs into spaces.
Delete ARG chars, and kill (save in kill ring) if KILLP is non-nil.
Interactively, ARG is the prefix arg (default 1)
and KILLP is t if a prefix arg was specified."
  (interactive "*p\nP")
  (let ((count arg))
    (save-excursion
      (while (and (> count 0) (not (bobp)))
	(if (= (preceding-char) ?\t)
	    (let ((col (current-column)))
	      (forward-char -1)
	      (setq col (- col (current-column)))
	      (insert-char ?\ col)
	      (delete-char 1)))
	(forward-char -1)
	(setq count (1- count)))))
  (delete-backward-char arg killp)
  ;; In overwrite mode, back over columns while clearing them out,
  ;; unless at end of line.
  (and overwrite-mode (not (eolp))
       (save-excursion (insert-char ?\  arg))))

(defun zap-to-char (arg char)
  "Kill up to and including ARG'th occurrence of CHAR.
Goes backward if ARG is negative; error if CHAR not found."
  (interactive "*p\ncZap to char: ")
  (kill-region (point) (progn
			 (search-forward (char-to-string char) nil nil arg)
;			 (goto-char (if (> arg 0) (1- (point)) (1+ (point))))
			 (point))))

(defun beginning-of-buffer (&optional arg)
  "Move point to the beginning of the buffer; leave mark at previous position.
With arg N, put point N/10 of the way from the beginning.

If the buffer is narrowed, this command uses the beginning and size
of the accessible part of the buffer.

Don't use this command in Lisp programs!
\(goto-char (point-min)) is faster and avoids clobbering the mark."
  (interactive "_P")
  (push-mark)
  (let ((size (- (point-max) (point-min))))
    (goto-char (if arg
		   (+ (point-min)
		      (if (> size 10000)
			  ;; Avoid overflow for large buffer sizes!
			  (* (prefix-numeric-value arg)
			     (/ size 10))
			(/ (+ 10 (* size (prefix-numeric-value arg))) 10)))
		 (point-min))))
  (if arg (forward-line 1)))

(defun end-of-buffer (&optional arg)
  "Move point to the end of the buffer; leave mark at previous position.
With arg N, put point N/10 of the way from the end.

If the buffer is narrowed, this command uses the beginning and size
of the accessible part of the buffer.

Don't use this command in Lisp programs!
\(goto-char (point-max)) is faster and avoids clobbering the mark."
  (interactive "_P")
  (push-mark)
  ;; XEmacs changes here.
  (let ((scroll-to-end (not (pos-visible-in-window-p (point-max))))
	(size (- (point-max) (point-min))))
    (goto-char (if arg
		   (- (point-max)
		      (if (> size 10000)
			  ;; Avoid overflow for large buffer sizes!
			  (* (prefix-numeric-value arg)
			     (/ size 10))
			(/ (* size (prefix-numeric-value arg)) 10)))
		 (point-max)))
    (cond (arg
           ;; If we went to a place in the middle of the buffer,
           ;; adjust it to the beginning of a line.
           (forward-line 1))
	  (scroll-to-end
           ;; If the end of the buffer is not already on the screen,
           ;; then scroll specially to put it near, but not at, the bottom.
           (recenter -3)))))

(defun mark-beginning-of-buffer (&optional arg)
  "Push a mark at the beginning of the buffer; leave point where it is.
With arg N, push mark N/10 of the way from the true beginning."
  (interactive "P")
  (push-mark (if arg
		 (if (> (buffer-size) 10000)
		     ;; Avoid overflow for large buffer sizes!
		     (* (prefix-numeric-value arg)
			(/ (buffer-size) 10))
		   (/ (+ 10 (* (buffer-size) (prefix-numeric-value arg))) 10))
	       (point-min))
             nil
             t))
(define-function 'mark-bob 'mark-beginning-of-buffer)

(defun mark-end-of-buffer (&optional arg)
  "Push a mark at the end of the buffer; leave point where it is.
With arg N, push mark N/10 of the way from the true end."
  (interactive "P")
  (push-mark (if arg
		 (- (1+ (buffer-size))
		    (if (> (buffer-size) 10000)
			;; Avoid overflow for large buffer sizes!
			(* (prefix-numeric-value arg)
			   (/ (buffer-size) 10))
		      (/ (* (buffer-size) (prefix-numeric-value arg)) 10)))
                 (point-max))
             nil
             t))
(define-function 'mark-eob 'mark-end-of-buffer)

(defun mark-whole-buffer ()
  "Put point at beginning and mark at end of buffer.
You probably should not use this function in Lisp programs;
it is usually a mistake for a Lisp function to use any subroutine
that uses or sets the mark."
  (interactive)
  (push-mark (point))
  (push-mark (point-max) nil t)
  (goto-char (point-min)))

(defun eval-current-buffer (&optional printflag)
  "Evaluate the current buffer as Lisp code.
Programs can pass argument PRINTFLAG which controls printing of output:
nil means discard it; anything else is stream for print."
  (interactive)
  (eval-buffer (current-buffer) printflag))

(defun count-words-buffer (b)
  (interactive "b")
  (save-excursion
    (let ((buf (or b (current-buffer))))
      (set-buffer buf)
      (message "Buffer has %d words"
	       (count-words-region (point-min) (point-max))))))

(defun count-words-region (start end)
  (interactive "r")
  (save-excursion
    (let ((n 0))
      (goto-char start)
      (while (< (point) end)
	(if (forward-word 1)
	    (setq n (1+ n))))
      (message "Region has %d words" n)
      n)))

(defun count-lines-region (start end)
  "Print number of lines and characters in the region."
  (interactive "_r")
  (let ((n (count-lines start end)))
    (message "Region has %d lines, %d characters"
	     n (- end start))
    n))

(defun count-lines-buffer (b)
  "Print number of lines and charcters in the specified buffer."
  (interactive "_b")
  (save-excursion
    (let ((buf (or b (current-buffer)))
          cnt)
      (set-buffer buf)
      (setq cnt (count-lines (point-min) (point-max)))
      (message "Region has %d lines, %d characters"
               cnt (- (point-max) (point-min)))
      cnt)))

(defun what-line ()
  "Print the current buffer line number and narrowed line number of point."
  (interactive "_")
  (let ((opoint (point)) start)
    (save-excursion
      (save-restriction
	(goto-char (point-min))
	(widen)
	(beginning-of-line)
	(setq start (point))
	(goto-char opoint)
	(beginning-of-line)
	(if (/= start 1)
	    (message "line %d (narrowed line %d)"
		     (1+ (count-lines 1 (point)))
		     (1+ (count-lines start (point))))
	  (message "Line %d" (1+ (count-lines 1 (point)))))))))


(defun count-lines (start end)
  "Return number of lines between START and END.
This is usually the number of newlines between them,
but can be one more if START is not equal to END
and the greater of them is not at the start of a line."
  (save-excursion
    (save-restriction
      (narrow-to-region start end)
      (goto-char (point-min))
      (if (eq selective-display t)
	  (save-match-data
	    (let ((done 0))
	      (while (re-search-forward "[\n\C-m]" nil t 40)
		(setq done (+ 40 done)))
	      (while (re-search-forward "[\n\C-m]" nil t 1)
		(setq done (+ 1 done)))
	      (goto-char (point-max))
	      (if (and (/= start end)
		       (not (bolp)))
		  (1+ done)
		done)))
	(- (buffer-size) (forward-line (buffer-size)))))))

(defun what-cursor-position ()
  "Print info on cursor position (on screen and within buffer)."
  (interactive "_")
  (let* ((char (following-char))
	 (beg (point-min))
	 (end (point-max))
         (pos (point))
	 (total (buffer-size))
	 (percent (if (> total 50000)
		      ;; Avoid overflow from multiplying by 100!
		      (/ (+ (/ total 200) (1- pos)) (max (/ total 100) 1))
		    (/ (+ (/ total 2) (* 100 (1- pos))) (max total 1))))
	 (hscroll (if (= (window-hscroll) 0)
		      ""
		    (format " Hscroll=%d" (window-hscroll))))
	 (col (current-column)))
    (if (= pos end)
	(if (or (/= beg 1) (/= end (1+ total)))
	    (message "point=%d of %d(%d%%) <%d - %d>  column %d %s"
		     pos total percent beg end col hscroll)
	  (message "point=%d of %d(%d%%)  column %d %s"
		   pos total percent col hscroll))
      (if (or (/= beg 1) (/= end (1+ total)))
	  (message "Char: %s (0%o, %d, 0x%x)  point=%d of %d(%d%%) <%d - %d>  column %d %s"
		   (text-char-description char) char char char pos total
		   percent beg end col hscroll)
	(message "Char: %s (0%o, %d, 0x%x)  point=%d of %d(%d%%)  column %d %s"
		 (text-char-description char) char char char pos total
		 percent col hscroll)))))

(defun fundamental-mode ()
  "Major mode not specialized for anything in particular.
Other major modes are defined by comparison with this one."
  (interactive)
  (kill-all-local-variables))


;; We define this, rather than making `eval' interactive,
;; for the sake of completion of names like eval-region, eval-current-buffer.
(defun eval-expression (expression)
  "Evaluate EXPRESSION and print value in minibuffer.
Value is also consed on to front of the variable `values'."
  (interactive "xEval: ")
  (setq values (cons (eval expression) values))
  (prin1 (car values) t))

(defun edit-and-eval-command (prompt command &optional history)
  "Prompting with PROMPT, let user edit COMMAND and eval result.
COMMAND is a Lisp expression.  Let user edit that expression in
the minibuffer, then read and evaluate the result."
  (let ((command (read-expression prompt
				  ;; first try to format the thing readably;
				  ;; and if that fails, print it normally.
				  (condition-case ()
				      (let ((print-readably t))
					(prin1-to-string command))
				    (error (prin1-to-string command)))
				  (or history '(command-history . 1)))))
    (or history (setq history 'command-history))
    (if (consp history)
	(setq history (car history)))
    (if (eq history t)
	nil
      ;; If command was added to the history as a string,
      ;; get rid of that.  We want only evallable expressions there.
      (if (stringp (car (symbol-value history)))
	  (set history (cdr (symbol-value history))))

      ;; If command to be redone does not match front of history,
      ;; add it to the history.
      (or (equal command (car (symbol-value history)))
	  (set history (cons command (symbol-value history)))))
    (eval command)))

(defun repeat-complex-command (arg)
  "Edit and re-evaluate last complex command, or ARGth from last.
A complex command is one which used the minibuffer.
The command is placed in the minibuffer as a Lisp form for editing.
The result is executed, repeating the command as changed.
If the command has been changed or is not the most recent previous command
it is added to the front of the command history.
You can use the minibuffer history commands \\<minibuffer-local-map>\\[next-history-element] and \\[previous-history-element]
to get different commands to edit and resubmit."
  (interactive "p")
  (let ((print-level nil))
    (edit-and-eval-command "Redo: "
			   (or (nth (1- arg) command-history)
			       (error ""))
			   (cons 'command-history arg))))

(defun goto-line (arg)
  "Goto line ARG, counting from line 1 at beginning of buffer."
  (interactive "NGoto line: ")
  (setq arg (prefix-numeric-value arg))
  (save-restriction
    (widen)
    (goto-char 1)
    (if (eq selective-display t)
	(re-search-forward "[\n\C-m]" nil 'end (1- arg))
      (forward-line (1- arg)))))

;Put this on C-x u, so we can force that rather than C-_ into startup msg
(define-function 'advertised-undo 'undo)

(defun undo (&optional arg)
  "Undo some previous changes.
Repeat this command to undo more changes.
A numeric argument serves as a repeat count."
  (interactive "*p")
  ;; If we don't get all the way through, make last-command indicate that
  ;; for the following command.
  (setq this-command t)
  (let ((modified (buffer-modified-p))
	(recent-save (recent-auto-save-p)))
    (or (eq (selected-window) (minibuffer-window))
	(message "Undo!"))
    (or (and (eq last-command 'undo)
	     (eq (current-buffer) last-undo-buffer))
	(progn (undo-start)
	       (undo-more 1)))
    (undo-more (or arg 1))
    ;; Don't specify a position in the undo record for the undo command.
    ;; Instead, undoing this should move point to where the change is.
    (let ((tail buffer-undo-list)
	  done)
      (while (and tail (not done) (not (null (car tail))))
	(if (integerp (car tail))
	    (progn
	      (setq done t)
	      (setq buffer-undo-list (delq (car tail) buffer-undo-list))))
	(setq tail (cdr tail))))
    (and modified (not (buffer-modified-p))
	 (delete-auto-save-file-if-necessary recent-save)))
  ;; If we do get all the way through, make this-command indicate that.
  (setq this-command 'undo))

(defvar pending-undo-list nil
  "Within a run of consecutive undo commands, list remaining to be undone.")

(defvar last-undo-buffer nil)

(defun undo-start ()
  "Set `pending-undo-list' to the front of the undo list.
The next call to `undo-more' will undo the most recently made change."
  (if (eq buffer-undo-list t)
      (error "No undo information in this buffer"))
  (setq pending-undo-list buffer-undo-list))

(defun undo-more (count)
  "Undo back N undo-boundaries beyond what was already undone recently.
Call `undo-start' to get ready to undo recent changes,
then call `undo-more' one or more times to undo them."
  (or pending-undo-list
      (error "No further undo information"))
  (setq pending-undo-list (primitive-undo count pending-undo-list)
	last-undo-buffer (current-buffer)))

(defun call-with-transparent-undo (fn &rest args)
  "Apply FN to ARGS, and then undo all changes made by FN to the current
buffer.  The undo records are processed even if FN returns non-locally.
There is no trace of the changes made by FN in the buffer's undo history.

You can use this in a write-file-hooks function with continue-save-buffer
to make the contents of a disk file differ from its in-memory buffer."
  (let ((buffer-undo-list nil)
	;; Kludge to prevent undo list truncation:
	(undo-high-threshold -1)
	(undo-threshold -1)
	(obuffer (current-buffer)))
    (unwind-protect
	(apply fn args)
      ;; Go to the buffer we will restore and make it writable:
      (set-buffer obuffer)
      (save-excursion
	(let ((buffer-read-only nil))
	  (save-restriction
	    (widen)
	    ;; Perform all undos, with further undo logging disabled:
	    (let ((tail buffer-undo-list))
	      (setq buffer-undo-list t)
	      (while tail
		(setq tail (primitive-undo (length tail) tail))))))))))


(defconst universal-argument-map
  (let ((map (make-sparse-keymap)))
    (set-keymap-default-binding map 'universal-argument-other-key)
    ;FSFmacs (define-key map [switch-frame] nil)
    (define-key map [(control u)] 'universal-argument-more)
    (define-key map ?- 'universal-argument-minus)
    (define-key map ?0 'digit-argument)
    (define-key map ?1 'digit-argument)
    (define-key map ?2 'digit-argument)
    (define-key map ?3 'digit-argument)
    (define-key map ?4 'digit-argument)
    (define-key map ?5 'digit-argument)
    (define-key map ?6 'digit-argument)
    (define-key map ?7 'digit-argument)
    (define-key map ?8 'digit-argument)
    (define-key map ?9 'digit-argument)
    map)
  "Keymap used while processing \\[universal-argument].")

(defvar universal-argument-num-events nil
  "Number of argument-specifying events read by `universal-argument'.
`universal-argument-other-key' uses this to discard those events
from (this-command-keys), and reread only the final command.")

(defun universal-argument ()
  "Begin a numeric argument for the following command.
Digits or minus sign following \\[universal-argument] make up the numeric argument.
\\[universal-argument] following the digits or minus sign ends the argument.
\\[universal-argument] without digits or minus sign provides 4 as argument.
Repeating \\[universal-argument] without digits or minus sign
 multiplies the argument by 4 each time."
  (interactive)
  (setq prefix-arg (list 4))
  (setq zmacs-region-stays t)
  (setq universal-argument-num-events (length (this-command-keys)))
  (setq overriding-terminal-local-map universal-argument-map))

;; A subsequent C-u means to multiply the factor by 4 if we've typed
;; nothing but C-u's; otherwise it means to terminate the prefix arg.
(defun universal-argument-more (arg)
  (interactive "P")
  (if (consp arg)
      (setq prefix-arg (list (* 4 (car arg))))
    (setq prefix-arg arg)
    (setq overriding-terminal-local-map nil))
  (setq zmacs-region-stays t)
  (setq universal-argument-num-events (length (this-command-keys))))

(defun negative-argument (arg)
  "Begin a negative numeric argument for the next command.
\\[universal-argument] following digits or minus sign ends the argument."
  (interactive "P")
  (cond ((integerp arg)
	  (setq prefix-arg (- arg)))
	 ((eq arg '-)
	  (setq prefix-arg nil))
	 (t
	  (setq prefix-arg '-)))
  (setq zmacs-region-stays t)
  (setq universal-argument-num-events (length (this-command-keys)))
  (setq overriding-terminal-local-map universal-argument-map))

(defun digit-argument (arg)
  "Part of the numeric argument for the next command.
\\[universal-argument] following digits or minus sign ends the argument."
  (interactive "P")
  (let* ((event last-command-event)
	 (key (and (key-press-event-p event)
		   (event-key event)))
	 (digit (and key (characterp key) (>= key ?0) (<= key ?9)
		     (- key ?0))))
    (if (null digit)
	(universal-argument-other-key arg)
      (cond ((integerp arg)
	     (setq prefix-arg (+ (* arg 10)
				 (if (< arg 0) (- digit) digit))))
	    ((eq arg '-)
	     ;; Treat -0 as just -, so that -01 will work.
	     (setq prefix-arg (if (zerop digit) '- (- digit))))
	    (t
	     (setq prefix-arg digit)))
      (setq zmacs-region-stays t)
      (setq universal-argument-num-events (length (this-command-keys)))
      (setq overriding-terminal-local-map universal-argument-map))))

;; For backward compatibility, minus with no modifiers is an ordinary
;; command if digits have already been entered.
(defun universal-argument-minus (arg)
  (interactive "P")
  (if (integerp arg)
      (universal-argument-other-key arg)
    (negative-argument arg)))

;; Anything else terminates the argument and is left in the queue to be
;; executed as a command.
(defun universal-argument-other-key (arg)
  (interactive "P")
  (setq prefix-arg arg)
  (setq zmacs-region-stays t)
  (let* ((key (this-command-keys))
	 ;; FSF calls silly function `listify-key-sequence' here.
	  (keylist (append key nil)))
    (setq unread-command-events
	   (append (nthcdr universal-argument-num-events keylist)
		   unread-command-events)))
  (reset-this-command-lengths)
  (setq overriding-terminal-local-map nil))


(defun forward-to-indentation (arg)
  "Move forward ARG lines and position at first nonblank character."
  (interactive "p")
  (forward-line arg)
  (skip-chars-forward " \t"))

(defun backward-to-indentation (arg)
  "Move backward ARG lines and position at first nonblank character."
  (interactive "p")
  (forward-line (- arg))
  (skip-chars-forward " \t"))

(defvar kill-whole-line nil
  "*If non-nil, `kill-line' with no arg at beg of line kills the whole line.")

(defun kill-line (&optional arg)
  "Kill the rest of the current line; if no nonblanks there, kill thru newline.
With prefix argument, kill that many lines from point.
Negative arguments kill lines backward.

When calling from a program, nil means \"no arg\",
a number counts as a prefix arg.

If `kill-whole-line' is non-nil, then kill the whole line
when given no argument at the beginning of a line."
  (interactive "*P")
  (kill-region (point)
	       ;; Don't shift point before doing the delete; that way,
	       ;; undo will record the right position of point.
	       (save-excursion
		 (if arg
		     (forward-line (prefix-numeric-value arg))
		   (if (eobp)
		       (signal 'end-of-buffer nil))
		   (if (or (looking-at "[ \t]*$") (and kill-whole-line (bolp)))
		       (forward-line 1)
		     (end-of-line)))
		 (point))))

(defun backward-kill-line nil
  "Kill back to the beginning of the line."
  (interactive)
  (let ((point (point)))
    (beginning-of-line nil)
    (kill-region (point) point)))


;;;; Window system cut and paste hooks.
;;;
;;; I think that kill-hooks is a better name and more general mechanism
;;; than interprogram-cut-function (from FSFmacs).  I don't like the behavior
;;; of interprogram-paste-function: ^Y should always come from the kill ring,
;;; not the X selection.  But if that were provided, it should be called (and
;;; behave as) yank-hooks instead.  -- jwz

;(defvar interprogram-cut-function nil
;  "Function to call to make a killed region available to other programs.
;
;Most window systems provide some sort of facility for cutting and
;pasting text between the windows of different programs.
;This variable holds a function that XEmacs calls whenever text
;is put in the kill ring, to make the new kill available to other
;programs.
;
;The function takes one or two arguments.
;The first argument, TEXT, is a string containing
;the text which should be made available.
;The second, PUSH, if non-nil means this is a \"new\" kill;
;nil means appending to an \"old\" kill.")
;
;(defvar interprogram-paste-function nil
;  "Function to call to get text cut from other programs.
;
;Most window systems provide some sort of facility for cutting and
;pasting text between the windows of different programs.
;This variable holds a function that Emacs calls to obtain
;text that other programs have provided for pasting.
;
;The function should be called with no arguments.  If the function
;returns nil, then no other program has provided such text, and the top
;of the Emacs kill ring should be used.  If the function returns a
;string, that string should be put in the kill ring as the latest kill.
;
;Note that the function should return a string only if a program other
;than Emacs has provided a string for pasting; if Emacs provided the
;most recent string, the function should return nil.  If it is
;difficult to tell whether Emacs or some other program provided the
;current string, it is probably good enough to return nil if the string
;is equal (according to `string=') to the last text Emacs provided.")

(defvar kill-hooks nil
  "Functions run when something is added to the XEmacs kill ring.
These functions are called with one argument, the string most recently
cut or copied.  You can use this to, for example, make the most recent 
kill become the X Clipboard selection.")


;;;; The kill ring data structure.

(defvar kill-ring nil
  "List of killed text sequences.
In order to maintain correct interaction with cut-and-paste facilities 
offered by window systems, the functions `kill-new', `kill-append', and
`current-kill' should be used to access the kill ring, instead of using
this variable directly.")

(defvar kill-ring-max 30
  "*Maximum length of kill ring before oldest elements are thrown away.")

(defvar kill-ring-yank-pointer nil
  "The tail of the kill ring whose car is the last thing yanked.")

(defun kill-new (string &optional replace)
  "Make STRING the latest kill in the kill ring.
Set the kill-ring-yank pointer to point to it.
Run `kill-hooks'.
Optional second argument REPLACE non-nil means that STRING will replace
the front of the kill ring, rather than being added to the list."
;  (and (fboundp 'menu-bar-update-yank-menu)
;       (menu-bar-update-yank-menu string (and replace (car kill-ring))))
  (if replace
      (setcar kill-ring string)
    (setq kill-ring (cons string kill-ring))
    (if (> (length kill-ring) kill-ring-max)
	(setcdr (nthcdr (1- kill-ring-max) kill-ring) nil)))
  (setq kill-ring-yank-pointer kill-ring)
;  (if interprogram-cut-function
;      (funcall interprogram-cut-function string (not replace)))
  (run-hook-with-args 'kill-hooks string))

(defun kill-append (string before-p)
  "Append STRING to the end of the latest kill in the kill ring.
If BEFORE-P is non-nil, prepend STRING to the kill.
Run `kill-hooks'."
  (kill-new (if before-p
		(concat string (car kill-ring))
	      (concat (car kill-ring) string)) t))

(defun current-kill (n &optional do-not-move)
  "Rotate the yanking point by N places, and then return that kill.
If optional arg DO-NOT-MOVE is non-nil, then don't actually move the 
yanking point\; just return the Nth kill forward."
  (or kill-ring (error "Kill ring is empty"))
  (let* ((tem (nthcdr (mod (- n (length kill-ring-yank-pointer))
                           (length kill-ring))
		      kill-ring)))
    (or do-not-move
	(setq kill-ring-yank-pointer tem))
    (car tem)))



;;;; Commands for manipulating the kill ring.

;;FSFmacs
;(defvar kill-read-only-ok nil
;  "*Non-nil means don't signal an error for killing read-only text.")

(defun kill-region (beg end &optional verbose) ; verbose is XEmacs addition
  "Kill between point and mark.
The text is deleted but saved in the kill ring.
The command \\[yank] can retrieve it from there.
\(If you want to kill and then yank immediately, use \\[copy-region-as-kill].)

This is the primitive for programs to kill text (as opposed to deleting it).
Supply two arguments, character numbers indicating the stretch of text
 to be killed.
Any command that calls this function is a \"kill command\".
If the previous command was also a kill command,
the text killed this time appends to the text killed last time
to make one entry in the kill ring."
  (interactive "*r\np")
;  (interactive
;   (let ((region-hack (and zmacs-regions (eq last-command 'yank))))
;     ;; This lets "^Y^W" work.  I think this is dumb, but zwei did it.
;     (if region-hack (zmacs-activate-region))
;     (prog1
;	 (list (point) (mark) current-prefix-arg)
;       (if region-hack (zmacs-deactivate-region)))))
  ;; beg and end can be markers but the rest of this function is
  ;; written as if they are only integers
  (if (markerp beg) (setq beg (marker-position beg)))
  (if (markerp end) (setq end (marker-position end)))
  (or (and beg end) (if zmacs-regions ;; rewritten for I18N3 snarfing
			(error "The region is not active now")
		      (error "The mark is not set now")))
  (if verbose (if buffer-read-only
		  (message "Copying %d characters"
		       (- (max beg end) (min beg end)))
		  (message "Killing %d characters"
		       (- (max beg end) (min beg end)))))
  (cond

   ;; I don't like this large change in behavior -- jwz
   ;; If the buffer is read-only, we should beep, in case the person
   ;; just isn't aware of this.  However, there's no harm in putting
   ;; the region's text in the kill ring, anyway.
   ;;((or (and buffer-read-only (not inhibit-read-only))
   ;;	  (text-property-not-all beg end 'read-only nil))
   ;; (if verbose (message "Copying %d characters"
   ;;		      (- (max beg end) (min beg end))))
   ;; (copy-region-as-kill beg end)
   ;; ;; This should always barf, and give us the correct error.
   ;; (if kill-read-only-ok
   ;;	  (message "Read only text copied to kill ring")
   ;;	(setq this-command 'kill-region)
   ;;	(barf-if-buffer-read-only)))

   ;; In certain cases, we can arrange for the undo list and the kill
   ;; ring to share the same string object.  This code does that.
   ((not (or (eq buffer-undo-list t)
	     (eq last-command 'kill-region)
	     ;; Use = since positions may be numbers or markers.
	     (= beg end)))
    ;; Don't let the undo list be truncated before we can even access it.
    (let ((undo-high-threshold (+ (- (max beg end) (min beg end)) 100))
	  ;(old-list buffer-undo-list)
	  tail)
      (delete-region beg end)
      ;; Search back in buffer-undo-list for this string,
      ;; in case a change hook made property changes.
      (setq tail buffer-undo-list)
      (while (not (stringp (car-safe (car-safe tail))))
	(setq tail (cdr tail)))
      ;; Take the same string recorded for undo
      ;; and put it in the kill-ring.
      (kill-new (car (car tail)))))

   (t
    ;; if undo is not kept, grab the string then delete it (which won't
    ;; add another string to the undo list).
    (copy-region-as-kill beg end)
    (delete-region beg end)))
  (setq this-command 'kill-region))

;; copy-region-as-kill no longer sets this-command, because it's confusing
;; to get two copies of the text when the user accidentally types M-w and
;; then corrects it with the intended C-w.
(defun copy-region-as-kill (beg end)
  "Save the region as if killed, but don't kill it.
Run `kill-hooks'."
  (interactive "r")
  (if (eq last-command 'kill-region)
      (kill-append (buffer-substring beg end) (< end beg))
    (kill-new (buffer-substring beg end)))
  nil)

(defun kill-ring-save (beg end)
  "Save the region as if killed, but don't kill it.
This command is similar to `copy-region-as-kill', except that it gives
visual feedback indicating the extent of the region being copied."
  (interactive "r")
  (copy-region-as-kill beg end)
  ;; copy before delay, for xclipboard's benefit
  (if (interactive-p)
      (let ((other-end (if (= (point) beg) end beg))
	    (opoint (point))
	    ;; Inhibit quitting so we can make a quit here
	    ;; look like a C-g typed as a command.
	    (inhibit-quit t))
	(if (pos-visible-in-window-p other-end (selected-window))
	    (progn
	      (goto-char other-end)
              (sit-for 1)
              (goto-char opoint)
              ;; If user quit, deactivate the mark
	      ;; as C-g would as a command.
	      (and quit-flag (mark)
                   (zmacs-deactivate-region)))
	  ;; too noisy. -- jwz
;	  (let* ((killed-text (current-kill 0))
;		 (message-len (min (length killed-text) 40)))
;	    (if (= (point) beg)
;		;; Don't say "killed"; that is misleading.
;		(message "Saved text until \"%s\""
;			(substring killed-text (- message-len)))
;	      (message "Saved text from \"%s\""
;		      (substring killed-text 0 message-len))))
	  ))))

(defun append-next-kill ()
  "Cause following command, if it kills, to append to previous kill."
  (interactive "_")
  (if (interactive-p)
      (progn
	(setq this-command 'kill-region)
	(message "If the next command is a kill, it will append"))
    (setq last-command 'kill-region)))

(defun yank-pop (arg)
  "Replace just-yanked stretch of killed text with a different stretch.
This command is allowed only immediately after a `yank' or a `yank-pop'.
At such a time, the region contains a stretch of reinserted
previously-killed text.  `yank-pop' deletes that text and inserts in its
place a different stretch of killed text.

With no argument, the previous kill is inserted.
With argument N, insert the Nth previous kill.
If N is negative, this is a more recent kill.

The sequence of kills wraps around, so that after the oldest one
comes the newest one."
  (interactive "*p")
  (if (not (eq last-command 'yank))
      (error "Previous command was not a yank"))
  (setq this-command 'yank)
  (let ((before (< (point) (mark t))))
    (delete-region (point) (mark t))
    (set-mark (point))
    (insert (current-kill arg))
    (if before (exchange-point-and-mark t))))

(defun yank (&optional arg)
  "Reinsert the last stretch of killed text.
More precisely, reinsert the stretch of killed text most recently
killed OR yanked.  Put point at end, and set mark at beginning.
With just C-u as argument, same but put point at beginning (and mark at end).
With argument N, reinsert the Nth most recently killed stretch of killed text.
See also the command \\[yank-pop]."
  (interactive "*P")
  ;; If we don't get all the way through, make last-command indicate that
  ;; for the following command.
  (setq this-command t)
  (push-mark (point))
  (insert (current-kill (cond
			 ((listp arg) 0)
			 ((eq arg '-) -1)
			 (t (1- arg)))))
  (if (consp arg)
      (exchange-point-and-mark t))
  ;; If we do get all the way through, make this-command indicate that.
  (setq this-command 'yank))

(defun rotate-yank-pointer (arg)
  "Rotate the yanking point in the kill ring.
With argument, rotate that many kills forward (or backward, if negative)."
  (interactive "p")
  (current-kill arg))


(defun insert-buffer (buffer)
  "Insert after point the contents of BUFFER.
Puts mark after the inserted text.
BUFFER may be a buffer or a buffer name."
  (interactive (list (progn (barf-if-buffer-read-only)
			    (read-buffer "Insert buffer: " 
					 ;; XEmacs: we have different args
					 (other-buffer (current-buffer) nil t)
					 t))))
  (or (bufferp buffer)
      (setq buffer (get-buffer buffer)))
  (let (start end newmark)
    (save-excursion
      (save-excursion
	(set-buffer buffer)
	(setq start (point-min) end (point-max)))
      (insert-buffer-substring buffer start end)
      (setq newmark (point)))
    (push-mark newmark))
  nil)

(defun append-to-buffer (buffer start end)
  "Append to specified buffer the text of the region.
It is inserted into that buffer before its point.

When calling from a program, give three arguments:
BUFFER (or buffer name), START and END.
START and END specify the portion of the current buffer to be copied."
  (interactive
   ;; XEmacs: we have different args to other-buffer
   (list (read-buffer "Append to buffer: " (other-buffer (current-buffer)
							 nil t))
	 (region-beginning) (region-end)))
  (let ((oldbuf (current-buffer)))
    (save-excursion
      (set-buffer (get-buffer-create buffer))
      (insert-buffer-substring oldbuf start end))))

(defun prepend-to-buffer (buffer start end)
  "Prepend to specified buffer the text of the region.
It is inserted into that buffer after its point.

When calling from a program, give three arguments:
BUFFER (or buffer name), START and END.
START and END specify the portion of the current buffer to be copied."
  (interactive "BPrepend to buffer: \nr")
  (let ((oldbuf (current-buffer)))
    (save-excursion
      (set-buffer (get-buffer-create buffer))
      (save-excursion
	(insert-buffer-substring oldbuf start end)))))

(defun copy-to-buffer (buffer start end)
  "Copy to specified buffer the text of the region.
It is inserted into that buffer, replacing existing text there.

When calling from a program, give three arguments:
BUFFER (or buffer name), START and END.
START and END specify the portion of the current buffer to be copied."
  (interactive "BCopy to buffer: \nr")
  (let ((oldbuf (current-buffer)))
    (save-excursion
      (set-buffer (get-buffer-create buffer))
      (erase-buffer)
      (save-excursion
	(insert-buffer-substring oldbuf start end)))))

;FSFmacs
;(define-error 'mark-inactive "The mark is not active now")

(defun mark (&optional force buffer)
  "Return this buffer's mark value as integer, or nil if no mark.

If `zmacs-regions' is true, then this returns nil unless the region is
currently in the active (highlighted) state.  With an argument of t, this
returns the mark (if there is one) regardless of the active-region state.
You should *generally* not use the mark unless the region is active, if
the user has expressed a preference for the active-region model.

If you are using this in an editing command, you are most likely making
a mistake; see the documentation of `set-mark'."
  (setq buffer (decode-buffer buffer))
;FSFmacs version:
;  (if (or force (not transient-mark-mode) mark-active mark-even-if-inactive)
;      (marker-position (mark-marker))
;    (signal 'mark-inactive nil)))
  (let ((m (mark-marker force buffer)))
    (and m (marker-position m))))

;;;#### FSFmacs
;;; Many places set mark-active directly, and several of them failed to also
;;; run deactivate-mark-hook.  This shorthand should simplify.
;(defsubst deactivate-mark ()
;  "Deactivate the mark by setting `mark-active' to nil.
;\(That makes a difference only in Transient Mark mode.)
;Also runs the hook `deactivate-mark-hook'."
;  (if transient-mark-mode
;      (progn
;	(setq mark-active nil)
;	(run-hooks 'deactivate-mark-hook))))

(defun set-mark (pos &optional buffer)
  "Set this buffer's mark to POS.  Don't use this function!
That is to say, don't use this function unless you want
the user to see that the mark has moved, and you want the previous
mark position to be lost.

Normally, when a new mark is set, the old one should go on the stack.
This is why most applications should use push-mark, not set-mark.

Novice Emacs Lisp programmers often try to use the mark for the wrong
purposes.  The mark saves a location for the user's convenience.
Most editing commands should not alter the mark.
To remember a location for internal use in the Lisp program,
store it in a Lisp variable.  Example:

   (let ((beg (point))) (forward-line 1) (delete-region beg (point)))."

  (setq buffer (decode-buffer buffer))
  (set-marker (mark-marker t buffer) pos buffer))

(defvar mark-ring nil
  "The list of former marks of the current buffer, most recent first.")
(make-variable-buffer-local 'mark-ring)
(put 'mark-ring 'permanent-local t)

(defvar mark-ring-max 16
  "*Maximum size of mark ring.  Start discarding off end if gets this big.")

(defvar global-mark-ring nil
  "The list of saved global marks, most recent first.")

(defconst global-mark-ring-max 16
  "*Maximum size of global mark ring.  \
Start discarding off end if gets this big.")

(defun set-mark-command (arg)
  "Set mark at where point is, or jump to mark.
With no prefix argument, set mark,  push old mark position on local mark
ring, and push mark on global mark ring.
With argument, jump to mark, and pop a new position for mark off the ring
\(does not affect global mark ring\).

Novice Emacs Lisp programmers often try to use the mark for the wrong
purposes.  See the documentation of `set-mark' for more information."
  (interactive "P")
  (if (null arg)
      (push-mark nil nil t)
    (if (null (mark t))
	(error "No mark set in this buffer")
      (goto-char (mark t))
      (pop-mark))))

(defun push-mark (&optional location nomsg activate-region buffer)
  "Set mark at LOCATION (point, by default) and push old mark on mark ring.
If the last global mark pushed was not in the current buffer,
also push LOCATION on the global mark ring.
Display `Mark set' unless the optional second arg NOMSG is non-nil.
Activate mark if optional third arg ACTIVATE-REGION non-nil.

Novice Emacs Lisp programmers often try to use the mark for the wrong
purposes.  See the documentation of `set-mark' for more information."
  (setq buffer (decode-buffer buffer))
  (if (null (mark t buffer))
      nil
    ;; The save-excursion / set-buffer is necessary because mark-ring
    ;; is a buffer local variable
    (save-excursion
      (set-buffer buffer)
      (setq mark-ring (cons (copy-marker (mark-marker t buffer)) mark-ring))
      (if (> (length mark-ring) mark-ring-max)
	  (progn
	    (move-marker (car (nthcdr mark-ring-max mark-ring)) nil buffer)
	    (setcdr (nthcdr (1- mark-ring-max) mark-ring) nil)))))
  (set-mark (or location (point buffer)) buffer)
  ;; Now push the mark on the global mark ring.
  (if (or (null global-mark-ring)
          (not (eq (marker-buffer (car global-mark-ring)) buffer)))
      ;; The last global mark pushed wasn't in this same buffer.
      (progn
        (setq global-mark-ring (cons (copy-marker (mark-marker t buffer))
                                     global-mark-ring))
        (if (> (length global-mark-ring) global-mark-ring-max)
            (progn
              (move-marker (car (nthcdr global-mark-ring-max global-mark-ring))
                           nil buffer)
              (setcdr (nthcdr (1- global-mark-ring-max) global-mark-ring) nil)))))
  (or nomsg executing-kbd-macro (> (minibuffer-depth) 0)
      (message "Mark set"))
  (if activate-region
      (progn
	(setq zmacs-region-stays t)
	(zmacs-activate-region)))
  nil)

(defun pop-mark ()
  "Pop off mark ring into the buffer's actual mark.
Does not set point.  Does nothing if mark ring is empty."
  (if mark-ring
      (progn
	(setq mark-ring (nconc mark-ring (list (copy-marker (mark-marker t)))))
	(set-mark (car mark-ring))
	(move-marker (car mark-ring) nil)
	(if (null (mark t)) (ding))
	(setq mark-ring (cdr mark-ring)))))

(define-function 'exchange-dot-and-mark 'exchange-point-and-mark)
(defun exchange-point-and-mark (&optional dont-activate-region)
  "Put the mark where point is now, and point where the mark is now.
The mark is activated unless DONT-ACTIVATE-REGION is non-nil."
  (interactive nil)
  (let ((omark (mark t)))
    (if (null omark)
	(error "No mark set in this buffer"))
    (set-mark (point))
    (goto-char omark)
    (or dont-activate-region (zmacs-activate-region))
    nil))

(defun mark-something (mark-fn movement-fn arg)
  "internal function used by mark-sexp, mark-word, etc."
  (let (newmark (pushp t))
    (save-excursion
      (if (and (eq last-command mark-fn) (mark))
	  ;; Extend the previous state in the same direction:
	  (progn
	    (if (< (mark) (point)) (setq arg (- arg)))
	    (goto-char (mark))
	    (setq pushp nil)))
      (funcall movement-fn arg)
      (setq newmark (point)))
    (if pushp
	(push-mark newmark nil t)
      ;; Do not mess with the mark stack, but merely adjust the previous state:
      (set-mark newmark)
      (activate-region))))

;(defun transient-mark-mode (arg)
;  "Toggle Transient Mark mode.
;With arg, turn Transient Mark mode on if arg is positive, off otherwise.
;
;In Transient Mark mode, when the mark is active, the region is highlighted.
;Changing the buffer \"deactivates\" the mark.
;So do certain other operations that set the mark
;but whose main purpose is something else--for example,
;incremental search, \\[beginning-of-buffer], and \\[end-of-buffer]."
;  (interactive "P")
;  (setq transient-mark-mode
;	(if (null arg)
;	    (not transient-mark-mode)
;	  (> (prefix-numeric-value arg) 0))))

(defun pop-global-mark ()
  "Pop off global mark ring and jump to the top location."
  (interactive)
  ;; Pop entries which refer to non-existent buffers.
  (while (and global-mark-ring (not (marker-buffer (car global-mark-ring))))
    (setq global-mark-ring (cdr global-mark-ring)))
  (or global-mark-ring
      (error "No global mark set"))
  (let* ((marker (car global-mark-ring))
	 (buffer (marker-buffer marker))
	 (position (marker-position marker)))
    (setq global-mark-ring (nconc (cdr global-mark-ring)
				  (list (car global-mark-ring))))
    (set-buffer buffer)
    (or (and (>= position (point-min))
	     (<= position (point-max)))
	(widen))
    (goto-char position)
    (switch-to-buffer buffer)))


(defvar next-line-add-newlines t
  "*If non-nil, `next-line' inserts newline to avoid `end of buffer' error.")

(defun next-line (arg)
  "Move cursor vertically down ARG lines.
If there is no character in the target line exactly under the current column,
the cursor is positioned after the character in that line which spans this
column, or at the end of the line if it is not long enough.

If there is no line in the buffer after this one, behavior depends on the
value of `next-line-add-newlines'.  If non-nil, it inserts a newline character
to create a line, and moves the cursor to that line.  Otherwise it moves the
cursor to the end of the buffer.

The command \\[set-goal-column] can be used to create
a semipermanent goal column to which this command always moves.
Then it does not try to move vertically.  This goal column is stored
in `goal-column', which is nil when there is none.

If you are thinking of using this in a Lisp program, consider
using `forward-line' instead.  It is usually easier to use
and more reliable (no dependence on goal column, etc.)."
  (interactive "_p")
  (if (and next-line-add-newlines (= arg 1))
      (let ((opoint (point)))
	(end-of-line)
	(if (eobp)
	    (newline 1)
	  (goto-char opoint)
	  (line-move arg)))
    (if (interactive-p)
	(condition-case nil
	    (line-move arg)
	  ((beginning-of-buffer end-of-buffer) (ding nil 'buffer-bound)))
      (line-move arg)))
  nil)

(defun previous-line (arg)
  "Move cursor vertically up ARG lines.
If there is no character in the target line exactly over the current column,
the cursor is positioned after the character in that line which spans this
column, or at the end of the line if it is not long enough.

The command \\[set-goal-column] can be used to create
a semipermanent goal column to which this command always moves.
Then it does not try to move vertically.

If you are thinking of using this in a Lisp program, consider using
`forward-line' with a negative argument instead.  It is usually easier
to use and more reliable (no dependence on goal column, etc.)."
  (interactive "_p")
  (if (interactive-p)
      (condition-case nil
	  (line-move (- arg))
	((beginning-of-buffer end-of-buffer) (ding nil 'buffer-bound)))
    (line-move (- arg)))
  nil)

(defvar track-eol nil
  "*Non-nil means vertical motion starting at end of line keeps to ends of lines.
This means moving to the end of each line moved onto.
The beginning of a blank line does not count as the end of a line.")

(defvar goal-column nil
  "*Semipermanent goal column for vertical motion, as set by \\[set-goal-column], or nil.")
(make-variable-buffer-local 'goal-column)

(defvar temporary-goal-column 0
  "Current goal column for vertical motion.
It is the column where point was
at the start of current run of vertical motion commands.
When the `track-eol' feature is doing its job, the value is 9999.")

;XEmacs: not yet ported, so avoid compiler warnings
(eval-when-compile
  (defvar inhibit-point-motion-hooks))

(defvar line-move-ignore-invisible nil
  "*Non-nil means \\[next-line] and \\[previous-line] ignore invisible lines.
Outline mode sets this.")

;; This is the guts of next-line and previous-line.
;; Arg says how many lines to move.
(defun line-move (arg)
  ;; Don't run any point-motion hooks, and disregard intangibility,
  ;; for intermediate positions.
  (let ((inhibit-point-motion-hooks t)
	(opoint (point))
	new)
    (unwind-protect
	(progn
	  (if (not (or (eq last-command 'next-line)
		       (eq last-command 'previous-line)))
	      (setq temporary-goal-column
		    (if (and track-eol (eolp)
			     ;; Don't count beg of empty line as end of line
			     ;; unless we just did explicit end-of-line.
			     (or (not (bolp)) (eq last-command 'end-of-line)))
			9999
		      (current-column))))
	  (if (and (not (integerp selective-display))
		   (not line-move-ignore-invisible))
	      ;; Use just newline characters.
	      (or (if (> arg 0)
		      (progn (if (> arg 1) (forward-line (1- arg)))
			     ;; This way of moving forward ARG lines
			     ;; verifies that we have a newline after the last one.
			     ;; It doesn't get confused by intangible text.
			     (end-of-line)
			     (zerop (forward-line 1)))
		    (and (zerop (forward-line arg))
			 (bolp)))
		  (signal (if (< arg 0)
			      'beginning-of-buffer
			    'end-of-buffer)
			  nil))
	    ;; Move by arg lines, but ignore invisible ones.
	    (while (> arg 0)
	      (end-of-line)
	      (and (zerop (vertical-motion 1))
		   (signal 'end-of-buffer nil))
	      ;; If the following character is currently invisible,
	      ;; skip all characters with that same `invisible' property value.
	      (while (and (not (eobp))
			  (let ((prop
				 (get-char-property (point) 'invisible)))
			    (if (eq buffer-invisibility-spec t)
				prop
			      (or (memq prop buffer-invisibility-spec)
				  (assq prop buffer-invisibility-spec)))))
		(if (get-text-property (point) 'invisible)
		    (goto-char (next-single-property-change (point) 'invisible))
		  (goto-char (next-extent-change (point)))))
	      (setq arg (1- arg)))
	    (while (< arg 0)
	      (beginning-of-line)
	      (and (zerop (vertical-motion -1))
		   (signal 'beginning-of-buffer nil))
	      (while (and (not (bobp))
			  (let ((prop
				 (get-char-property (1- (point)) 'invisible)))
			    (if (eq buffer-invisibility-spec t)
				prop
			      (or (memq prop buffer-invisibility-spec)
				  (assq prop buffer-invisibility-spec)))))
		(if (get-text-property (1- (point)) 'invisible)
		    (goto-char (previous-single-property-change (point) 'invisible))
		  (goto-char (previous-extent-change (point)))))
	      (setq arg (1+ arg))))
	  (move-to-column (or goal-column temporary-goal-column)))
      ;; Remember where we moved to, go back home,
      ;; then do the motion over again
      ;; in just one step, with intangibility and point-motion hooks
      ;; enabled this time.
      (setq new (point))
      (goto-char opoint)
      (setq inhibit-point-motion-hooks nil)
      (goto-char new)))
  nil)

;;; Many people have said they rarely use this feature, and often type
;;; it by accident.  Maybe it shouldn't even be on a key.
(put 'set-goal-column 'disabled t)

(defun set-goal-column (arg)
  "Set the current horizontal position as a goal for \\[next-line] and \\[previous-line].
Those commands will move to this position in the line moved to
rather than trying to keep the same horizontal position.
With a non-nil argument, clears out the goal column
so that \\[next-line] and \\[previous-line] resume vertical motion.
The goal column is stored in the variable `goal-column'."
  (interactive "_P")
  (if arg
      (progn
        (setq goal-column nil)
        (message "No goal column"))
    (setq goal-column (current-column))
    (message (substitute-command-keys
	      "Goal column %d (use \\[set-goal-column] with an arg to unset it)")
	     goal-column))
  nil)


;;; deleted FSFmacs terminal randomness hscroll-point-visible stuff.

(defun scroll-other-window-down (lines)
  "Scroll the \"other window\" down.
For more details, see the documentation for `scroll-other-window'."
  (interactive "P")
  (scroll-other-window
   ;; Just invert the argument's meaning.
   ;; We can do that without knowing which window it will be.
   (if (eq lines '-) nil
     (if (null lines) '-
       (- (prefix-numeric-value lines))))))

(defun beginning-of-buffer-other-window (arg)
  "Move point to the beginning of the buffer in the other window.
Leave mark at previous position.
With arg N, put point N/10 of the way from the true beginning."
  (interactive "P")
  (let ((orig-window (selected-window))
	(window (other-window-for-scrolling)))
    ;; We use unwind-protect rather than save-window-excursion
    ;; because the latter would preserve the things we want to change.
    (unwind-protect
	(progn
	  (select-window window)
	  ;; Set point and mark in that window's buffer.
	  (beginning-of-buffer arg)
	  ;; Set point accordingly.
	  (recenter '(t)))
      (select-window orig-window))))

(defun end-of-buffer-other-window (arg)
  "Move point to the end of the buffer in the other window.
Leave mark at previous position.
With arg N, put point N/10 of the way from the true end."
  (interactive "P")
  ;; See beginning-of-buffer-other-window for comments.
  (let ((orig-window (selected-window))
	(window (other-window-for-scrolling)))
    (unwind-protect
	(progn
	  (select-window window)
	  (end-of-buffer arg)
	  (recenter '(t)))
      (select-window orig-window))))

(defun transpose-chars (arg)
  "Interchange characters around point, moving forward one character.
With prefix arg ARG, effect is to take character before point
and drag it forward past ARG other characters (backward if ARG negative).
If no argument and at end of line, the previous two chars are exchanged."
  (interactive "*P")
  (and (null arg) (eolp) (forward-char -1))
  (transpose-subr 'forward-char (prefix-numeric-value arg)))

(defun transpose-words (arg)
  "Interchange words around point, leaving point at end of them.
With prefix arg ARG, effect is to take word before or around point
and drag it forward past ARG other words (backward if ARG negative).
If ARG is zero, the words around or after point and around or after mark
are interchanged."
  (interactive "*p")
  (transpose-subr 'forward-word arg))

(defun transpose-sexps (arg)
  "Like \\[transpose-words] but applies to sexps.
Does not work on a sexp that point is in the middle of
if it is a list or string."
  (interactive "*p")
  (transpose-subr 'forward-sexp arg))

(defun transpose-lines (arg)
  "Exchange current line and previous line, leaving point after both.
With argument ARG, takes previous line and moves it past ARG lines.
With argument 0, interchanges line point is in with line mark is in."
  (interactive "*p")
  (transpose-subr #'(lambda (arg)
		     (if (= arg 1)
			 (progn
			   ;; Move forward over a line,
			   ;; but create a newline if none exists yet.
			   (end-of-line)
			   (if (eobp)
			       (newline)
			     (forward-char 1)))
		       (forward-line arg)))
		  arg))

(eval-when-compile
  ;; avoid byte-compiler warnings...
  (defvar start1)
  (defvar start2)
  (defvar end1)
  (defvar end2))

; start[12] and end[12] used in transpose-subr-1 below
(defun transpose-subr (mover arg)
  (let (start1 end1 start2 end2)
    (if (= arg 0)
	(progn
	  (save-excursion
	    (funcall mover 1)
	    (setq end2 (point))
	    (funcall mover -1)
	    (setq start2 (point))
	    (goto-char (mark t))
	    (funcall mover 1)
	    (setq end1 (point))
	    (funcall mover -1)
	    (setq start1 (point))
	    (transpose-subr-1))
	  (exchange-point-and-mark t)))
    (while (> arg 0)
      (funcall mover -1)
      (setq start1 (point))
      (funcall mover 1)
      (setq end1 (point))
      (funcall mover 1)
      (setq end2 (point))
      (funcall mover -1)
      (setq start2 (point))
      (transpose-subr-1)
      (goto-char end2)
      (setq arg (1- arg)))
    (while (< arg 0)
      (funcall mover -1)
      (setq start2 (point))
      (funcall mover -1)
      (setq start1 (point))
      (funcall mover 1)
      (setq end1 (point))
      (funcall mover 1)
      (setq end2 (point))
      (transpose-subr-1)
      (setq arg (1+ arg)))))

; start[12] and end[12] used free
(defun transpose-subr-1 ()
  (if (> (min end1 end2) (max start1 start2))
      (error "Don't have two things to transpose"))
  (let ((word1 (buffer-substring start1 end1))
	(word2 (buffer-substring start2 end2)))
    (delete-region start2 end2)
    (goto-char start2)
    (insert word1)
    (goto-char (if (< start1 start2) start1
		 (+ start1 (- (length word1) (length word2)))))
    (delete-char (length word1))
    (insert word2)))

(defvar comment-column 32
  "*Column to indent right-margin comments to.
Setting this variable automatically makes it local to the current buffer.
Each mode establishes a different default value for this variable; you
can set the value for a particular mode using that mode's hook.")
(make-variable-buffer-local 'comment-column)

(defvar comment-start nil
  "*String to insert to start a new comment, or nil if no comment syntax.")

(defvar comment-start-skip nil
  "*Regexp to match the start of a comment plus everything up to its body.
If there are any \\(...\\) pairs, the comment delimiter text is held to begin
at the place matched by the close of the first pair.")

(defvar comment-end ""
  "*String to insert to end a new comment.
Should be an empty string if comments are terminated by end-of-line.")

(defconst comment-indent-hook nil
  "Obsolete variable for function to compute desired indentation for a comment.
Use `comment-indent-function' instead.
This function is called with no args with point at the beginning of
the comment's starting delimiter.")

(defvar comment-indent-function
  ;; XEmacs - add at least one space after the end of the text on the
  ;; current line...  
  #'(lambda ()
      (save-excursion 
	(beginning-of-line) 
	(let ((eol (save-excursion (end-of-line) (point))))
	  (and comment-start-skip
	       (re-search-forward comment-start-skip eol t)
	       (setq eol (match-beginning 0)))
	  (goto-char eol)
	  (skip-chars-backward " \t")
	  (max comment-column (1+ (current-column))))))
  "Function to compute desired indentation for a comment.
This function is called with no args with point at the beginning of
the comment's starting delimiter.")

(defconst block-comment-start nil
  "*String to insert to start a new comment on a line by itself.
If nil, use `comment-start' instead.
Note that the regular expression `comment-start-skip' should skip this string
as well as the `comment-start' string.")

(defconst block-comment-end nil
  "*String to insert to end a new comment on a line by itself.
Should be an empty string if comments are terminated by end-of-line.
If nil, use `comment-end' instead.")

(defun indent-for-comment ()
  "Indent this line's comment to comment column, or insert an empty comment."
  (interactive "*")
  (let* ((empty (save-excursion (beginning-of-line)
				(looking-at "[ \t]*$")))
	 (starter (or (and empty block-comment-start) comment-start))
	 (ender (or (and empty block-comment-end) comment-end)))
    (if (null starter)
	(error "No comment syntax defined")
      (let* ((eolpos (save-excursion (end-of-line) (point)))
	     cpos indent begpos)
	(beginning-of-line)
	(if (re-search-forward comment-start-skip eolpos 'move)
	    (progn (setq cpos (point-marker))
		   ;; Find the start of the comment delimiter.
		   ;; If there were paren-pairs in comment-start-skip,
		   ;; position at the end of the first pair.
		   (if (match-end 1)
		       (goto-char (match-end 1))
		     ;; If comment-start-skip matched a string with
		     ;; internal whitespace (not final whitespace) then
		     ;; the delimiter start at the end of that
		     ;; whitespace.  Otherwise, it starts at the
		     ;; beginning of what was matched.
		     (skip-syntax-backward " " (match-beginning 0))
		     (skip-syntax-backward "^ " (match-beginning 0)))))
	(setq begpos (point))
	;; Compute desired indent.
	(if (= (current-column)
	       (setq indent (if comment-indent-hook
				(funcall comment-indent-hook)
			      (funcall comment-indent-function))))
	    (goto-char begpos)
	  ;; If that's different from current, change it.
	  (skip-chars-backward " \t")
	  (delete-region (point) begpos)
	  (indent-to indent))
	;; An existing comment?
	(if cpos 
	    (progn (goto-char cpos)
		   (set-marker cpos nil))
	  ;; No, insert one.
	  (insert starter)
	  (save-excursion
	    (insert ender)))))))

(defun set-comment-column (arg)
  "Set the comment column based on point.
With no arg, set the comment column to the current column.
With just minus as arg, kill any comment on this line.
With any other arg, set comment column to indentation of the previous comment
 and then align or create a comment on this line at that column."
  (interactive "P")
  (if (eq arg '-)
      (kill-comment nil)
    (if arg
	(progn
	  (save-excursion
	    (beginning-of-line)
	    (re-search-backward comment-start-skip)
	    (beginning-of-line)
	    (re-search-forward comment-start-skip)
	    (goto-char (match-beginning 0))
	    (setq comment-column (current-column))
	    (message "Comment column set to %d" comment-column))
	  (indent-for-comment))
      (setq comment-column (current-column))
      (message "Comment column set to %d" comment-column))))

(defun kill-comment (arg)
  "Kill the comment on this line, if any.
With argument, kill comments on that many lines starting with this one."
  ;; this function loses in a lot of situations.  it incorrectly recognises
  ;; comment delimiters sometimes (ergo, inside a string), doesn't work
  ;; with multi-line comments, can kill extra whitespace if comment wasn't
  ;; through end-of-line, et cetera.
  (interactive "*P")
  (or comment-start-skip (error "No comment syntax defined"))
  (let ((count (prefix-numeric-value arg)) endc)
    (while (> count 0)
      (save-excursion
	(end-of-line)
	(setq endc (point))
	(beginning-of-line)
	(and (string< "" comment-end)
	     (setq endc
		   (progn
		     (re-search-forward (regexp-quote comment-end) endc 'move)
		     (skip-chars-forward " \t")
		     (point))))
	(beginning-of-line)
	(if (re-search-forward comment-start-skip endc t)
	    (progn
	      (goto-char (match-beginning 0))
	      (skip-chars-backward " \t")
	      (kill-region (point) endc)
	      ;; to catch comments a line beginnings
	      (indent-according-to-mode))))
      (if arg (forward-line 1))
      (setq count (1- count)))))

(defun comment-region (beg end &optional arg)
  "Comment or uncomment each line in the region.
With just C-u prefix arg, uncomment each line in region.
Numeric prefix arg ARG means use ARG comment characters.
If ARG is negative, delete that many comment characters instead.
Comments are terminated on each line, even for syntax in which newline does
not end the comment.  Blank lines do not get comments."
  ;; if someone wants it to only put a comment-start at the beginning and
  ;; comment-end at the end then typing it, C-x C-x, closing it, C-x C-x
  ;; is easy enough.  No option is made here for other than commenting
  ;; every line.
  (interactive "r\nP")
  (or comment-start (error "No comment syntax is defined"))
  (if (> beg end) (let (mid) (setq mid beg beg end end mid)))
  (save-excursion
    (save-restriction
      (let ((cs comment-start) (ce comment-end)
	    numarg)
        (if (consp arg) (setq numarg t)
	  (setq numarg (prefix-numeric-value arg))
	  ;; For positive arg > 1, replicate the comment delims now,
	  ;; then insert the replicated strings just once.
	  (while (> numarg 1)
	    (setq cs (concat cs comment-start)
		  ce (concat ce comment-end))
	    (setq numarg (1- numarg))))
	;; Loop over all lines from BEG to END.
        (narrow-to-region beg end)
        (goto-char beg)
        (while (not (eobp))
          (if (or (eq numarg t) (< numarg 0))
	      (progn
		;; Delete comment start from beginning of line.
		(if (eq numarg t)
		    (while (looking-at (regexp-quote cs))
		      (delete-char (length cs)))
		  (let ((count numarg))
		    (while (and (> 1 (setq count (1+ count)))
				(looking-at (regexp-quote cs)))
		      (delete-char (length cs)))))
		;; Delete comment end from end of line.
                (if (string= "" ce)
		    nil
		  (if (eq numarg t)
		      (progn
			(end-of-line)
			;; This is questionable if comment-end ends in
			;; whitespace.  That is pretty brain-damaged,
			;; though.
			(skip-chars-backward " \t")
			(if (and (>= (- (point) (point-min)) (length ce))
				 (save-excursion
				   (backward-char (length ce))
				   (looking-at (regexp-quote ce))))
			    (delete-char (- (length ce)))))
		    (let ((count numarg))
		      (while (> 1 (setq count (1+ count)))
			(end-of-line)
			;; This is questionable if comment-end ends in
			;; whitespace.  That is pretty brain-damaged though
			(skip-chars-backward " \t")
			(save-excursion
			  (backward-char (length ce))
			  (if (looking-at (regexp-quote ce))
			      (delete-char (length ce))))))))
		(forward-line 1))
	    ;; Insert at beginning and at end.
            (if (looking-at "[ \t]*$") ()
              (insert cs)
              (if (string= "" ce) ()
                (end-of-line)
                (insert ce)))
            (search-forward "\n" nil 'move)))))))

(defun prefix-region (prefix)
  "Add a prefix string to each line between mark and point."
  (interactive "sPrefix string: ")
  (if prefix
      (let ((count (count-lines (mark) (point))))
 	(goto-char (min (mark) (point)))
 	(while (> count 0)
          (setq count (1- count))
 	  (beginning-of-line 1)
 	  (insert prefix)
 	  (end-of-line 1)
 	  (forward-char 1)))))


(defun backward-word (arg &optional buffer)
  "Move backward until encountering the end of a word.
With argument, do this that many times.
In programs, it is faster to call `forward-word' with negative arg."
  (interactive "_p")
  (forward-word (- arg) buffer))

(defun mark-word (arg)
  "Set mark arg words away from point."
  (interactive "p")
  (mark-something 'mark-word 'forward-word arg))

(defun kill-word (arg)
  "Kill characters forward until encountering the end of a word.
With argument, do this that many times."
  (interactive "*p")
  (kill-region (point) (save-excursion (forward-word arg) (point))))

(defun backward-kill-word (arg)
  "Kill characters backward until encountering the end of a word.
With argument, do this that many times."
  (interactive "*p")
  (kill-word (- arg)))

(defun current-word (&optional strict)
  "Return the word point is on (or a nearby word) as a string.
If optional arg STRICT is non-nil, return nil unless point is within
or adjacent to a word.
If point is not between two word-constituent characters, but immediately
follows one, move back first.
Otherwise, if point precedes a word constituent, move forward first.
Otherwise, move backwards until a word constituent is found and get that word;
if you a newlines is reached first, move forward instead."
  (save-excursion
    (let ((oldpoint (point)) (start (point)) (end (point)))
      (skip-syntax-backward "w_") (setq start (point))
      (goto-char oldpoint)
      (skip-syntax-forward "w_") (setq end (point))
      (if (and (eq start oldpoint) (eq end oldpoint))
	  ;; Point is neither within nor adjacent to a word.
	  (and (not strict)
               (progn
                 ;; Look for preceding word in same line.
                 (skip-syntax-backward "^w_"
                                       (save-excursion
                                         (beginning-of-line) (point)))
                 (if (bolp)
		     ;; No preceding word in same line.
		     ;; Look for following word in same line.
                     (progn
                       (skip-syntax-forward "^w_"
					    (save-excursion
                                              (end-of-line) (point)))
                       (setq start (point))
                       (skip-syntax-forward "w_")
                       (setq end (point)))
                     (setq end (point))
                     (skip-syntax-backward "w_")
                     (setq start (point)))
		 (buffer-substring start end)))
          (buffer-substring start end)))))

(defvar fill-prefix nil
  "*String for filling to insert at front of new line, or nil for none.
Setting this variable automatically makes it local to the current buffer.")
(make-variable-buffer-local 'fill-prefix)

(defvar auto-fill-inhibit-regexp nil
  "*Regexp to match lines which should not be auto-filled.")

(defun do-auto-fill ()
  (let (give-up)
    (or (and auto-fill-inhibit-regexp
	     (save-excursion (beginning-of-line)
			     (looking-at auto-fill-inhibit-regexp)))
	(while (and (not give-up) (> (current-column) fill-column))
	  ;; Determine where to split the line.
	  (let ((fill-prefix fill-prefix)
		(fill-point
		 (let ((opoint (point))
		       bounce
		       (first t))
		   (save-excursion
		     (move-to-column (1+ fill-column))
		     ;; Move back to a word boundary.
		     (while (or first
				;; If this is after period and a single space,
				;; move back once more--we don't want to break
				;; the line there and make it look like a
				;; sentence end.
				(and (not (bobp))
				     (not bounce)
				     sentence-end-double-space
				     (save-excursion (forward-char -1)
						     (and (looking-at "\\. ")
							  (not (looking-at "\\.  "))))))
		       (setq first nil)
		       (skip-chars-backward "^ \t\n")
		       ;; If we find nowhere on the line to break it,
		       ;; break after one word.  Set bounce to t
		       ;; so we will not keep going in this while loop.
		       (if (bolp)
			   (progn
			     (re-search-forward "[ \t]" opoint t)
			     (setq bounce t)))
		       (skip-chars-backward " \t"))
		     ;; Let fill-point be set to the place where we end up.
		     (point)))))

	    ;; I'm not sure why Stig made this change but it breaks
	    ;; auto filling in at least C mode so I'm taking it back
	    ;; out.  --cet
	    ;; XEmacs - adaptive fill.
	    ;;(maybe-adapt-fill-prefix
	    ;; (or from (setq from (save-excursion (beginning-of-line)
	    ;;					 (point))))
	    ;; (or to   (setq to (save-excursion (beginning-of-line 2)
	    ;;				       (point))))
	    ;; t)

	    ;; If that place is not the beginning of the line,
	    ;; break the line there.
	    (if (save-excursion
		  (goto-char fill-point)
		  (not (bolp)))
		(let ((prev-column (current-column)))
		  ;; If point is at the fill-point, do not `save-excursion'.
		  ;; Otherwise, if a comment prefix or fill-prefix is inserted,
		  ;; point will end up before it rather than after it.
		  (if (save-excursion
			(skip-chars-backward " \t")
			(= (point) fill-point))
		      (indent-new-comment-line)
		    (save-excursion
		      (goto-char fill-point)
		      (indent-new-comment-line)))
		  ;; If making the new line didn't reduce the hpos of
		  ;; the end of the line, then give up now;
		  ;; trying again will not help.
		  (if (>= (current-column) prev-column)
		      (setq give-up t)))
	      ;; No place to break => stop trying.
	      (setq give-up t)))))))

(defvar comment-multi-line t ; XEmacs - this works well with adaptive fill
  "*Non-nil means \\[indent-new-comment-line] should continue same comment
on new line, with no new terminator or starter.
This is obsolete because you might as well use \\[newline-and-indent].")

(defun indent-new-comment-line (&optional soft)
  "Break line at point and indent, continuing comment if within one.
This indents the body of the continued comment
under the previous comment line.

This command is intended for styles where you write a comment per line,
starting a new comment (and terminating it if necessary) on each line.
If you want to continue one comment across several lines, use \\[newline-and-indent].

If a fill column is specified, it overrides the use of the comment column
or comment indentation.

The inserted newline is marked hard if `use-hard-newlines' is true, 
unless optional argument SOFT is non-nil."
  (interactive)
  (let (comcol comstart)
    (skip-chars-backward " \t")
    (delete-region (point)
		   (progn (skip-chars-forward " \t")
			  (point)))
    (if soft (insert ?\n) (newline 1))
    (if fill-prefix
	(progn
	  (indent-to-left-margin)
	  (insert fill-prefix))
    ;; #### - Eric Eide reverts to v18 semantics for this function in
    ;; fa-extras, which I'm not gonna do.  His changes are to (1) execute
    ;; the save-excursion below unconditionally, and (2) uncomment the check
    ;; for (not comment-multi-line) further below.  --Stig 
      (if (not comment-multi-line)
	  (save-excursion
	    (if (and comment-start-skip
		     (let ((opoint (point)))
		       (forward-line -1)
		       (re-search-forward comment-start-skip opoint t)))
		;; The old line is a comment.
		;; Set WIN to the pos of the comment-start.
		;; But if the comment is empty, look at preceding lines
		;; to find one that has a nonempty comment.

		;; If comment-start-skip contains a \(...\) pair,
		;; the real comment delimiter starts at the end of that pair.
		(let ((win (or (match-end 1) (match-beginning 0))))
		  (while (and (eolp) (not (bobp))
			      (let (opoint)
				(beginning-of-line)
				(setq opoint (point))
				(forward-line -1)
				(re-search-forward comment-start-skip opoint t)))
		    (setq win (or (match-end 1) (match-beginning 0))))
		  ;; Indent this line like what we found.
		  (goto-char win)
		  (setq comcol (current-column))
		  (setq comstart
			(buffer-substring (point) (match-end 0)))))))
      (if (and comcol (not fill-prefix))  ; XEmacs - (ENE) from fa-extras.
	  (let ((comment-column comcol)
		(comment-start comstart)
		(comment-end comment-end))
	    (and comment-end (not (equal comment-end ""))
  ;	       (if (not comment-multi-line)
		     (progn
		       (forward-char -1)
		       (insert comment-end)
		       (forward-char 1))
  ;		 (setq comment-column (+ comment-column (length comment-start))
  ;		       comment-start "")
  ;		   )
		 )
	    (if (not (eolp))
		(setq comment-end ""))
	    (insert ?\n)
	    (forward-char -1)
	    (indent-for-comment)
	    (save-excursion
	      ;; Make sure we delete the newline inserted above.
	      (end-of-line)
	      (delete-char 1)))
	(indent-according-to-mode)))))

(defun auto-fill-mode (&optional arg)
  "Toggle auto-fill mode.
With arg, turn auto-fill mode on if and only if arg is positive.
In Auto-Fill mode, inserting a space at a column beyond `current-fill-column'
automatically breaks the line at a previous space."
  (interactive "P")
  (prog1 (setq auto-fill-function
	       (if (if (null arg)
		       (not auto-fill-function)
		       (> (prefix-numeric-value arg) 0))
		   'do-auto-fill
		   nil))
    (redraw-modeline)))

;; This holds a document string used to document auto-fill-mode.
(defun auto-fill-function ()
  "Automatically break line at a previous space, in insertion of text."
  nil)

(defun turn-on-auto-fill ()
  "Unconditionally turn on Auto Fill mode."
  (auto-fill-mode 1))

(defun set-fill-column (arg)
  "Set `fill-column' to current column, or to argument if given.
The variable `fill-column' has a separate value for each buffer."
  (interactive "_P")
  (setq fill-column (if (integerp arg) arg (current-column)))
  (message "fill-column set to %d" fill-column))

(defun set-selective-display (arg)
  "Set `selective-display' to ARG; clear it if no arg.
When the value of `selective-display' is a number > 0,
lines whose indentation is >= that value are not displayed.
The variable `selective-display' has a separate value for each buffer."
  (interactive "P")
  (if (eq selective-display t)
      (error "selective-display already in use for marked lines"))
  (let ((current-vpos
	 (save-restriction
	   (narrow-to-region (point-min) (point))
	   (goto-char (window-start))
	   (vertical-motion (window-height)))))
    (setq selective-display
	  (and arg (prefix-numeric-value arg)))
    (recenter current-vpos))
  (set-window-start (selected-window) (window-start (selected-window)))
  ;; #### doesn't localize properly:
  (princ "selective-display set to " t)
  (prin1 selective-display t)
  (princ "." t))

(defun nuke-selective-display ()
  "Ensure that the buffer is not in selective-display mode.
If `selective-display' is t, then restore the buffer text to it's original
state before disabling selective display." 
  ;; by Stig@hackvan.com
  (interactive)
  (and (eq t selective-display)
       (save-excursion
	 (save-restriction
	   (widen)
	   (goto-char (point-min))
	   (let ((mod-p (buffer-modified-p))
		 (buffer-read-only nil))
	     (while (search-forward "\r" nil t)
	       (delete-char -1)
	       (insert "\n"))
	     (set-buffer-modified-p mod-p)
	     ))))
  (setq selective-display nil))

(add-hook 'change-major-mode-hook 'nuke-selective-display)

(defvar overwrite-mode-textual (purecopy " Ovwrt")
  "The string displayed in the modeline when in overwrite mode.")
(defvar overwrite-mode-binary (purecopy " Bin Ovwrt")
  "The string displayed in the modeline when in binary overwrite mode.")

(defun overwrite-mode (arg)
  "Toggle overwrite mode.
With arg, turn overwrite mode on iff arg is positive.
In overwrite mode, printing characters typed in replace existing text
on a one-for-one basis, rather than pushing it to the right.  At the
end of a line, such characters extend the line.  Before a tab,
such characters insert until the tab is filled in.
\\[quoted-insert] still inserts characters in overwrite mode; this
is supposed to make it easier to insert characters when necessary."
  (interactive "P")
  (setq overwrite-mode
	(if (if (null arg) (not overwrite-mode)
	      (> (prefix-numeric-value arg) 0))
	    'overwrite-mode-textual))
  (redraw-modeline))

(defun binary-overwrite-mode (arg)
  "Toggle binary overwrite mode.
With arg, turn binary overwrite mode on iff arg is positive.
In binary overwrite mode, printing characters typed in replace
existing text.  Newlines are not treated specially, so typing at the
end of a line joins the line to the next, with the typed character
between them.  Typing before a tab character simply replaces the tab
with the character typed.
\\[quoted-insert] replaces the text at the cursor, just as ordinary
typing characters do.

Note that binary overwrite mode is not its own minor mode; it is a
specialization of overwrite-mode, entered by setting the
`overwrite-mode' variable to `overwrite-mode-binary'."
  (interactive "P")
  (setq overwrite-mode
	(if (if (null arg)
		(not (eq overwrite-mode 'overwrite-mode-binary))
	      (> (prefix-numeric-value arg) 0))
	    'overwrite-mode-binary))
  (redraw-modeline))

(defvar line-number-mode nil
  "*Non-nil means display line number in modeline.")

(defun line-number-mode (arg)
  "Toggle Line Number mode.
With arg, turn Line Number mode on iff arg is positive.
When Line Number mode is enabled, the line number appears
in the modeline."
  (interactive "P")
  (setq line-number-mode
	(if (null arg) (not line-number-mode)
	  (> (prefix-numeric-value arg) 0)))
  (redraw-modeline))

(defvar column-number-mode nil
  "*Non-nil means display column number in modeline.")

(defun column-number-mode (arg)
  "Toggle Column Number mode.
With arg, turn Column Number mode on iff arg is positive.
When Column Number mode is enabled, the column number appears
in the modeline."
  (interactive "P")
  (setq column-number-mode
	(if (null arg) (not column-number-mode)
	  (> (prefix-numeric-value arg) 0)))
  (redraw-modeline))


(defvar blink-matching-paren t
  "*Non-nil means show matching open-paren when close-paren is inserted.")

(defvar blink-matching-paren-distance 12000
  "*If non-nil, is maximum distance to search for matching open-paren.")

(defconst blink-matching-delay 1
  "*The number of seconds that `blink-matching-open' will delay at a match.")

(defconst blink-matching-paren-dont-ignore-comments nil
  "*Non-nil means `blink-matching-paren' should not ignore comments.")

(defun blink-matching-open ()
  "Move cursor momentarily to the beginning of the sexp before point."
  (interactive "_")
  (and (> (point) (1+ (point-min)))
       blink-matching-paren
       ;; Verify an even number of quoting characters precede the close.
       (= 1 (logand 1 (- (point)
			 (save-excursion
			   (forward-char -1)
			   (skip-syntax-backward "/\\")
			   (point)))))
       (let* ((oldpos (point))
	      (parse-sexp-ignore-comments t) ; to avoid C++ lossage
	      (blinkpos)
	      (mismatch))
	 (save-excursion
	   (save-restriction
	     (if blink-matching-paren-distance
		 (narrow-to-region (max (point-min)
					(- (point) blink-matching-paren-distance))
				   oldpos))
	     (condition-case ()
		 (let ((parse-sexp-ignore-comments
			(and parse-sexp-ignore-comments
			     (not blink-matching-paren-dont-ignore-comments))))
		   (setq blinkpos (scan-sexps oldpos -1)))
	       (error nil)))
	   (and blinkpos
		(/= (char-syntax (char-after blinkpos))
		    ?\$)
		(setq mismatch
		      (or (null (matching-paren (char-after blinkpos)))
			  (/= (char-after (1- oldpos))
			      (matching-paren (char-after blinkpos))))))
	   (if mismatch (setq blinkpos nil))
	   (if blinkpos
	       (progn
		(goto-char blinkpos)
		(if (pos-visible-in-window-p)
		    (sit-for blink-matching-delay)
		  (goto-char blinkpos)
		  (message
		   "Matches %s"
		   ;; Show what precedes the open in its line, if anything.
		   (if (save-excursion
			 (skip-chars-backward " \t")
			 (not (bolp)))
		       (buffer-substring (progn (beginning-of-line) (point))
					 (1+ blinkpos))
		     ;; Show what follows the open in its line, if anything.
		     (if (save-excursion
			   (forward-char 1)
			   (skip-chars-forward " \t")
			   (not (eolp)))
                         (buffer-substring blinkpos
                                           (progn (end-of-line) (point)))
		       ;; Otherwise show the previous nonblank line,
		       ;; if there is one.
		       (if (save-excursion
			     (skip-chars-backward "\n \t")
			     (not (bobp)))
			   (concat
			    (buffer-substring (progn
					       (skip-chars-backward "\n \t")
					       (beginning-of-line)
					       (point))
					      (progn (end-of-line)
						     (skip-chars-backward " \t")
						     (point)))
			    ;; Replace the newline and other whitespace with `...'.
			    "..."
			    (buffer-substring blinkpos (1+ blinkpos)))
			 ;; There is nothing to show except the char itself.
			 (buffer-substring blinkpos (1+ blinkpos))))))))
	     (cond (mismatch
		    (message "Mismatched parentheses"))
		   ((not blink-matching-paren-distance)
		    (message "Unmatched parenthesis"))))))))

;Turned off because it makes dbx bomb out.
(setq blink-paren-function 'blink-matching-open)

(eval-when-compile (defvar myhelp))	; suppress compiler warning

(defun set-variable (var val)
  "Set VARIABLE to VALUE.  VALUE is a Lisp object.
When using this interactively, supply a Lisp expression for VALUE.
If you want VALUE to be a string, you must surround it with doublequotes.

If VARIABLE has a `variable-interactive' property, that is used as if
it were the arg to `interactive' (which see) to interactively read the value."
  (interactive
   (let* ((var (read-variable "Set variable: "))
	  ;; #### - yucky code replication here.  This should use something
	  ;; from help.el or hyper-apropos.el 
	  (minibuffer-help-form
	   '(funcall myhelp))
	  (myhelp
	   #'(lambda ()
	      (with-output-to-temp-buffer "*Help*"
		(prin1 var)
		(princ "\nDocumentation:\n")
		(princ (substring (documentation-property var 'variable-documentation)
				  1))
		(if (boundp var)
		    (let ((print-length 20))
		      (princ "\n\nCurrent value: ")
		      (prin1 (symbol-value var))))
		(save-excursion
		  (set-buffer standard-output)
		  (help-mode))
		nil))))
     (list var
	   (let ((prop (get var 'variable-interactive)))
	     (if prop
		 ;; Use VAR's `variable-interactive' property
		 ;; as an interactive spec for prompting.
		 (call-interactively (list 'lambda '(arg)
					   (list 'interactive prop)
					   'arg))
	       (eval-minibuffer (format "Set %s to value: " var)))))))
  (set var val))

(defun activate-region ()
  "Activate the region, if `zmacs-regions' is true.
Setting `zmacs-regions' to true causes LISPM-style active regions to be used.
This function has no effect if `zmacs-regions' is false."
  (interactive)
  (and zmacs-regions (zmacs-activate-region)))

(defsubst region-exists-p ()
  "Non-nil iff the region exists.
If active regions are in use (i.e. `zmacs-regions' is true), this means that
 the region is active.  Otherwise, this means that the user has pushed
 a mark in this buffer at some point in the past.
The functions `region-beginning' and `region-end' can be used to find the
 limits of the region."
  (not (null (mark))))

(defun region-active-p ()
  "Non-nil iff the region is active.
If `zmacs-regions' is true, this is equivalent to `region-exists-p'.
Otherwise, this function always returns false."
  (and zmacs-regions zmacs-region-extent))

(defun capitalize-region-or-word (arg)
  "Capitalize the selected region or the following word (or ARG words)."
  (interactive "p")
  (if (region-active-p) (capitalize-region (region-beginning) (region-end))
    (capitalize-word arg)))

(defun upcase-region-or-word (arg)
  "Upcase the selected region or the following word (or ARG words)."
  (interactive "p")
  (if (region-active-p) (upcase-region (region-beginning) (region-end))
    (upcase-word arg)))

(defun downcase-region-or-word (arg)
  "Downcase the selected region or the following word (or ARG words)."
  (interactive "p")
  (if (region-active-p) (downcase-region (region-beginning) (region-end))
    (downcase-word arg)))

;;;
;;; Most of the zmacs code is now in elisp.  The only thing left in C
;;; are the variables zmacs-regions, zmacs-region-active-p and
;;; zmacs-region-stays plus the function zmacs_update_region which
;;; calls the lisp level zmacs-update-region.  It must remain since it
;;; must be called by core C code.
;;;

(defvar zmacs-activate-region-hook nil
  "Function or functions called when the region becomes active;
see the variable `zmacs-regions'.")

(defvar zmacs-deactivate-region-hook nil
  "Function or functions called when the region becomes inactive;
see the variable `zmacs-regions'.")

(defvar zmacs-update-region-hook nil
  "Function or functions called when the active region changes.
This is called after each command that sets `zmacs-region-stays' to t.
See the variable `zmacs-regions'.")

(defvar zmacs-region-extent nil
  "The extent of the zmacs region; don't use this.")

(defvar zmacs-region-rectangular-p nil
  "Whether the zmacs region is a rectangle; don't use this.")

(defun zmacs-make-extent-for-region (region)
  ;; Given a region, this makes an extent in the buffer which holds that
  ;; region, for highlighting purposes.  If the region isn't associated
  ;; with a buffer, this does nothing.
  (let ((buffer nil)
	(valid (and (extentp zmacs-region-extent)
		    (extent-object zmacs-region-extent)
		    (buffer-live-p (extent-object zmacs-region-extent))))
	start end)
    (cond ((consp region)
	   (setq start (min (car region) (cdr region))
		 end (max (car region) (cdr region))
		 valid (and valid
			    (eq (marker-buffer (car region))
				(extent-object zmacs-region-extent)))
		 buffer (marker-buffer (car region))))
	  (t
	   (signal 'error (list "invalid region" region))))

    (if valid
	nil
      ;; The condition case is in case any of the extents are dead or
      ;; otherwise incapacitated.
      (condition-case ()
	  (if (listp zmacs-region-extent)
	      (mapcar 'delete-extent zmacs-region-extent)
	    (delete-extent zmacs-region-extent))
	(error nil)))

    (if valid
	(set-extent-endpoints zmacs-region-extent start end)
      (setq zmacs-region-extent (make-extent start end buffer))

      ;; Make the extent be closed on the right, which means that if
      ;; characters are inserted exactly at the end of the extent, the
      ;; extent will grow to cover them.  This is important for shell
      ;; buffers - suppose one makes a region, and one end is at point-max.
      ;; If the shell produces output, that marker will remain at point-max
      ;; (its position will increase).  So it's important that the extent
      ;; exhibit the same behavior, lest the region covered by the extent
      ;; (the visual indication), and the region between point and mark
      ;; (the actual region value) become different!
      (set-extent-property zmacs-region-extent 'end-open nil)

      ;; use same priority as mouse-highlighting so that conflicts between
      ;; the region extent and a mouse-highlighted extent are resolved by
      ;; the usual size-and-endpoint-comparison method.
      (set-extent-priority zmacs-region-extent mouse-highlight-priority)
      (set-extent-face zmacs-region-extent 'zmacs-region)

      ;; #### It might be better to actually break
      ;; default-mouse-track-next-move-rect out of mouse.el so that we
      ;; can use its logic here.
      (cond
       (zmacs-region-rectangular-p
	(setq zmacs-region-extent (list zmacs-region-extent))
	(default-mouse-track-next-move-rect start end zmacs-region-extent)
	))

      zmacs-region-extent)))

(defun zmacs-region-buffer ()
  "Return the buffer containing the zmacs region, or nil."
  ;; #### this is horrible and kludgy!  This stuff needs to be rethought.
  (and zmacs-regions zmacs-region-active-p
       (or (marker-buffer (mark-marker t))
	   (and (extent-live-p zmacs-region-extent)
	        (buffer-live-p (extent-object zmacs-region-extent))
	        (extent-object zmacs-region-extent)))))

(defun zmacs-activate-region ()
  "Make the region between `point' and `mark' be active (highlighted),
if `zmacs-regions' is true.  Only a very small number of commands
should ever do this.  Calling this function will call the hook
`zmacs-activate-region-hook', if the region was previously inactive.
Calling this function ensures that the region stays active after the
current command terminates, even if `zmacs-region-stays' is not set.
Returns t if the region was activated (i.e. if `zmacs-regions' if t)."
  (if (not zmacs-regions)
      nil
    (setq zmacs-region-active-p t
	  zmacs-region-stays t
	  zmacs-region-rectangular-p (and (boundp 'mouse-track-rectangle-p)
					  mouse-track-rectangle-p))
    (if (marker-buffer (mark-marker t))
	(zmacs-make-extent-for-region (cons (point-marker t) (mark-marker t))))
    (run-hooks 'zmacs-activate-region-hook)
    t))

(defun zmacs-deactivate-region ()
  "Make the region between `point' and `mark' no longer be active,
if `zmacs-regions' is true.  You shouldn't need to call this; the
command loop calls it when appropriate.  Calling this function will
call the hook `zmacs-deactivate-region-hook', if the region was
previously active.  Returns t if the region had been active, nil
otherwise."
  (if (not zmacs-region-active-p)
      nil
    (setq zmacs-region-active-p nil
	  zmacs-region-stays nil
	  zmacs-region-rectangular-p nil)
    (if zmacs-region-extent
	(let ((inhibit-quit t))
	  (if (listp zmacs-region-extent)
	      (mapcar 'delete-extent zmacs-region-extent)
	    (delete-extent zmacs-region-extent))
	  (setq zmacs-region-extent nil)))
    (run-hooks 'zmacs-deactivate-region-hook)
    t))

(defun zmacs-update-region ()
  "Update the highlighted region between `point' and `mark'.
You shouldn't need to call this; the command loop calls it
when appropriate.  Calling this function will call the hook
`zmacs-update-region-hook', if the region is active."
  (if zmacs-region-active-p
      (progn
	(if (marker-buffer (mark-marker t))
	    (zmacs-make-extent-for-region (cons (point-marker t)
						(mark-marker t))))
	(run-hooks 'zmacs-update-region-hook))))

;;;;;;
;;;;;; echo area stuff
;;;;;;

;;; The `message-stack' is an alist of labels with messages; the first
;;; message in this list is always in the echo area.  A call to
;;; `display-message' inserts a label/message pair at the head of the
;;; list, and removes any other pairs with that label.  Calling
;;; `clear-message' causes any pair with matching label to be removed,
;;; and this may cause the displayed message to change or vanish.  If
;;; the label arg is nil, the entire message stack is cleared.
;;;
;;; Message/error filtering will be a little tricker to implement than
;;; logging, since messages can be built up incrementally
;;; using clear-message followed by repeated calls to append-message
;;; (this happens with error messages).  For messages which aren't
;;; created this way, filtering could be implemented at display-message
;;; very easily.
;;;
;;; Bits of the logging code are borrowed from log-messages.el by
;;; Robert Potter (rpotter@grip.cis.upenn.edu).

;; need this to terminate the currently-displayed message
;; ("Loading simple ...")
(or (fboundp 'display-message) (send-string-to-terminal "\n"))

(defvar message-stack nil
  "An alist of label/string pairs representing active echo-area messages.
The first element in the list is currently displayed in the echo area.
Do not modify this directly--use the `message' or 
`display-message'/`clear-message' functions.")

(defvar remove-message-hook 'log-message
  "A function or list of functions to be called when a message is removed
from the echo area at the bottom of the frame.  The label of the removed
message is passed as the first argument, and the text of the message
as the second argument.")

(defvar log-message-max-size 50000
  "Maximum size of the \" *Message-Log*\" buffer.  See `log-message'.")

(defvar log-message-ignore-regexps
  '("^Mark set$"
    "^Undo!$"
    "^Quit$"
    "^\\(Beginning\\|End\\) of buffer$"
    "^Fontifying"
    "^\\(Failing \\)?\\([Ww]rapped \\)?\\([Rr]egexp \\)?I-search\\( backward\\)?:"
    "^Mark saved where search started$"
    "^Making completion list"
    "^Matches "					; paren-matching message
    "^Type .* to \\(remove help\\|restore the other\\) window."
    "^M-x .* (bound to key"			; teach-extended-commands
    "^(No changes need to be saved)$"
    "^(No files need saving)$"
    "^\\(Parsing messages\\|Reading attributes\\|Generating summary\\|Building threads\\|Converting\\)\\.\\.\\. [0-9]+$"	; vm
    "^End of message \d+"			; vm
    "^Parsing error messages\\.\\.\\.[0-9]+"	; compile
    "^Parsed [0-9]+ of [0-9]+ ([0-9]+%)$"	; w3
    "^\\(Formatting Summary\\|Reading active file\\|Checking new news\\|Looking for crossposts\\|Marking crossposts\\|MHSPOOL:\\|NNSPOOL:\\|NNTP:\\|\\(Uns\\|S\\)ubscribing new newsgroups\\)\\.\\.\\. *[0-9]+%$"	; gnus
    "^Adding glyphs\\.\\.\\. ([0-9]+%)\\( done\\)?$"	; outl-mouse
    "^->"				        ; bbdb prompt
    )
  "List of regular expressions matching messages which shouldn't be logged.
See `log-message'.  

Ideally, packages which generate messages which might need to be ignored
should label them with 'progress, 'prompt, or 'no-log, so they can be 
filtered by the log-message-ignore-labels.")

(defvar log-message-ignore-labels 
  '(help-echo command progress prompt no-log garbage-collecting auto-saving)
  "List of symbols indicating labels of messages which shouldn't be logged.
See `display-message' for some common labels.  See also `log-message'.")

;Subsumed by view-lossage
;(defun show-message-log ()
;  "Show the \" *Message-Log*\" buffer, which contains old messages and errors."
;  (interactive)
;  (pop-to-buffer " *Message-Log*"))

(defvar log-message-filter-function 'log-message-filter
  "Value must be a function of two arguments: a symbol (label) and 
a string (messsage).  It should return non-nil to indicate a message
should be logged.  Possible values include 'log-message-filter and
'log-message-filter-errors-only.")

(defun log-message-filter (label message)
  "Default value of log-message-filter-function.
Mesages whose text matches one of the log-message-ignore-regexps
or whose label appears in log-message-ignore-labels are not saved."
  (let ((r  log-message-ignore-regexps)
	(ok (not (memq label log-message-ignore-labels))))
    (while (and r ok)
      (if (save-match-data (string-match (car r) message))
	  (setq ok nil))
      (setq r (cdr r)))
    ok))

(defun log-message-filter-errors-only (label message)
  "For use as the log-message-filter-function.  Only logs error messages."
  (eq label 'error))

(defun log-message (label message)
  "Stuff a copy of the message into the \" *Message-Log*\" buffer,
if it satisfies the log-message-filter-function.

For use on remove-message-hook."
  (if (and (not noninteractive)
	   (funcall log-message-filter-function label message))
      (save-excursion
	(set-buffer (get-buffer-create " *Message-Log*"))
	(goto-char (point-max))
	;; (insert (concat (upcase (symbol-name label)) ": "  message "\n"))
	(insert message "\n")
	(if (> (point-max) (max log-message-max-size (point-min)))
	    (progn
	      ;; trim log to ~90% of max size
	      (goto-char (max (- (point-max)
				 (truncate (* 0.9 log-message-max-size)))
			      (point-min)))
	      (forward-line 1)
	      (delete-region (point-min) (point)))))))

(defun message-displayed-p (&optional return-string frame)
  "Return a non-nil value if a message is presently displayed in the\n\
minibuffer's echo area.  If optional argument RETURN-STRING is non-nil,\n\
return a string containing the message, otherwise just return t."
  ;; by definition, a message is displayed if the echo area buffer is
  ;; non-empty (see also echo_area_active()).  It had better also
  ;; be the case that message-stack is nil exactly when the echo area
  ;; is non-empty.
  (let ((buffer (get-buffer " *Echo Area*")))
    (and (< (point-min buffer) (point-max buffer))
	 (if return-string
	     (buffer-substring nil nil buffer)
	   t))))

;;; Returns the string which remains in the echo area, or nil if none.
;;; If label is nil, the whole message stack is cleared.
(defun clear-message (&optional label frame stdout-p no-restore)
  "Remove any message with the given LABEL from the message-stack,
erasing it from the echo area if it's currently displayed there.
If a message remains at the head of the message-stack and NO-RESTORE
is nil, it will be displayed.  The string which remains in the echo
area will be returned, or nil if the message-stack is now empty.
If LABEL is nil, the entire message-stack is cleared.

Unless you need the return value or you need to specify a lable,
you should just use (message nil)."
  (or frame (setq frame (selected-frame)))
  (let ((clear-stream (and message-stack (eq 'stream (frame-type frame)))))
    (remove-message label frame)
    (let ((buffer (get-buffer " *Echo Area*"))
	  (zmacs-region-stays zmacs-region-stays)) ; preserve from change
      (erase-buffer buffer))
    (if clear-stream
	(send-string-to-terminal ?\n stdout-p))
    (if no-restore
	nil			; just preparing to put another msg up
      (if message-stack
	  (let ((oldmsg  (cdr (car message-stack))))
	    (raw-append-message oldmsg frame stdout-p)
	    oldmsg)
	;; ### should we (redisplay-echo-area) here?  messes some things up.
	nil))))

(defun remove-message (&optional label frame)
  ;; If label is nil, we want to remove all matching messages.
  ;; Must reverse the stack first to log them in the right order.
  (let ((log nil))
    (while (and message-stack
		(or (null label)	; null label means clear whole stack
		    (eq label (car (car message-stack)))))
      (setq log (cons (car message-stack) log))
    (setq message-stack (cdr message-stack)))
    (let ((s  message-stack))
      (while (cdr s)
	(let ((msg (car (cdr s))))
	  (if (eq label (car msg))
	      (progn
		(setq log (cons msg log))
		(setcdr s (cdr (cdr s))))
	    (setq s (cdr s))))))
    ;; (possibly) log each removed message
    (while log
      (condition-case e
	  (run-hook-with-args 'remove-message-hook
			      (car (car log)) (cdr (car log)))
	(error (setq remove-message-hook nil)
	       (message "remove-message-hook error: %s" e)
	       (sit-for 2)
	       (erase-buffer (get-buffer " *Echo Area*"))
	       (signal (car e) (cdr e))))
      (setq log (cdr log)))))

(defun append-message (label message &optional frame stdout-p)
  (or frame (setq frame (selected-frame)))
  ;; add a new entry to the message-stack, or modify an existing one
  (let ((top (car message-stack)))
    (if (eq label (car top))
	(setcdr top (concat (cdr top) message))
      (setq message-stack (cons (cons label message) message-stack))))
  (raw-append-message message frame stdout-p))

;; really append the message to the echo area.  no fiddling with message-stack.
(defun raw-append-message (message &optional frame stdout-p)
  (if (eq message "") nil
    (let ((buffer (get-buffer " *Echo Area*"))
	  (zmacs-region-stays zmacs-region-stays)) ; preserve from change
      (save-excursion
	(set-buffer buffer)
	(insert message))
      ;; Conditionalizing on the device type in this way is not that clean,
      ;; but neither is having a device method, as I originally implemented
      ;; it: all non-stream devices behave in the same way.  Perhaps
      ;; the cleanest way is to make the concept of a "redisplayable"
      ;; device, which stream devices are not.  Look into this more if
      ;; we ever create another non-redisplayable device type (e.g.
      ;; processes?  printers?).

      ;; Don't redisplay the echo area if we are executing a macro.
      (if (not executing-kbd-macro)
	  (if (eq 'stream (frame-type frame))
	      (send-string-to-terminal message stdout-p)
	    (redisplay-echo-area))))))

(defun display-message (label message &optional frame stdout-p)
  "Print a one-line message at the bottom of the frame.  First argument
LABEL is an identifier for this message.  MESSAGE is the string to display.
Use `clear-message' to remove a labelled message.

Here are some standard labels (those marked with `*' are not logged
by default--see the `log-message-ignore-labels' variable):
    message       default label used by the `message' function
    error         default label used for reporting errors
  * progress      progress indicators like \"Converting... 45%\"
  * prompt        prompt-like messages like \"I-search: foo\"
  * no-log        messages that should never be logged"
  (clear-message label frame stdout-p t)
  (append-message label message frame stdout-p))

;;; may eventually be frame-dependent
(defun current-message-label (frame)
  (if message-stack
      (car (car message-stack))
    nil))

(defun message (fmt &rest args)
  "Print a one-line message at the bottom of the frame.
The arguments are the same as to `format'.

If the only argument is nil, clear any existing message; let the
minibuffer contents show."
  ;; questionable junk in the C code
  ;; (if (framep default-minibuffer-frame)
  ;;     (make-frame-visible default-minibuffer-frame))
  (if (and (null fmt) (null args))
      (progn
	(clear-message nil)
	nil)
    (let ((str (apply 'format fmt args)))
      (display-message 'message str)
      str)))

;;;;;;
;;;;;; warning stuff
;;;;;;

(defvar log-warning-minimum-level 'info
  "Minimum level of warnings that should be logged.
The warnings in levels below this are completely ignored, as if they never
happened.

The recognized warning levels, in decreasing order of priority, are
'emergency, 'alert, 'critical, 'error, 'warning, 'notice, 'info, and
'debug.

See also `display-warning-minimum-level'.

You can also control which warnings are displayed on a class-by-class
basis.  See `display-warning-suppressed-classes' and
`log-warning-suppressed-classes'.")

(defvar display-warning-minimum-level 'info
  "Minimum level of warnings that should be displayed.
The warnings in levels below this are completely ignored, as if they never
happened.

The recognized warning levels, in decreasing order of priority, are
'emergency, 'alert, 'critical, 'error, 'warning, 'notice, 'info, and
'debug.

See also `log-warning-minimum-level'.

You can also control which warnings are displayed on a class-by-class
basis.  See `display-warning-suppressed-classes' and
`log-warning-suppressed-classes'.")

(defvar log-warning-suppressed-classes nil
  "List of classes of warnings that shouldn't be logged or displayed.
If any of the CLASS symbols associated with a warning is the same as
any of the symbols listed here, the warning will be completely ignored,
as it they never happened.

NOTE: In most circumstances, you should *not* set this variable.
Set `display-warning-suppressed-classes' instead.  That way the suppressed
warnings are not displayed but are still unobtrusively logged.

See also `log-warning-minimum-level' and `display-warning-minimum-level'.")

(defvar display-warning-suppressed-classes nil
  "List of classes of warnings that shouldn't be displayed.
If any of the CLASS symbols associated with a warning is the same as
any of the symbols listed here, the warning will not be displayed.
The warning will still logged in the *Warnings* buffer (unless also
contained in `log-warning-suppressed-classes'), but the buffer will
not be automatically popped up.

See also `log-warning-minimum-level' and `display-warning-minimum-level'.")

(defvar warning-count 0
  "Count of the number of warning messages displayed so far.")

(defconst warning-level-alist '((emergency . 8)
				(alert . 7)
				(critical . 6)
				(error . 5)
				(warning . 4)
				(notice . 3)
				(info . 2)
				(debug . 1)))

(defun warning-level-p (level)
  "Non-nil if LEVEL specifies a warning level."
  (and (symbolp level) (assq level warning-level-alist)))

;; If you're interested in rewriting this function, be aware that it
;; could be called at arbitrary points in a Lisp program (when a
;; built-in function wants to issue a warning, it will call out to
;; this function the next time some Lisp code is evaluated).  Therefore,
;; this function *must* not permanently modify any global variables
;; (e.g. the current buffer) except those that specifically apply
;; to the warning system.

(defvar before-init-deferred-warnings nil)

(defun after-init-display-warnings ()
  "Display warnings deferred till after the init file is run.
Warnings that occur before then are deferred so that warning
suppression in the .emacs file will be honored."
  (while before-init-deferred-warnings
    (apply 'display-warning (car before-init-deferred-warnings))
    (setq before-init-deferred-warnings
	  (cdr before-init-deferred-warnings))))

(add-hook 'after-init-hook 'after-init-display-warnings)

(defun display-warning (class message &optional level)
  "Display a warning message.
CLASS should be a symbol describing what sort of warning this is, such
as `resource' or `key-mapping'.  A list of such symbols is also
accepted. (Individual classes can be suppressed; see
`display-warning-suppressed-classes'.) Optional argument LEVEL can
be used to specify a priority for the warning, other than default priority
`warning'. (See `display-warning-minimum-level').  The message is
inserted into the *Warnings* buffer, which is made visible at appropriate
times."
  (or level (setq level 'warning))
  (or (listp class) (setq class (list class)))
  (check-argument-type 'warning-level-p level)
  (if (not init-file-loaded)
      (setq before-init-deferred-warnings
	    (cons (list class message level) before-init-deferred-warnings))
    (catch 'ignored
      (let ((display-p t)
	    (level-num (cdr (assq level warning-level-alist))))
	(if (< level-num (cdr (assq log-warning-minimum-level
				    warning-level-alist)))
	    (throw 'ignored nil))
	(if (intersection class log-warning-suppressed-classes)
	    (throw 'ignored nil))
	
	(if (< level-num (cdr (assq display-warning-minimum-level
				    warning-level-alist)))
	    (setq display-p nil))
	(if (and display-p
		 (intersection class display-warning-suppressed-classes))
	    (setq display-p nil))
	(save-excursion
	  (let ((buffer (get-buffer-create "*Warnings*")))
	    (if display-p
		;; The C code looks at display-warning-tick to determine
		;; when it should call `display-warning-buffer'.  Change it
		;; to get the C code's attention.
		(setq display-warning-tick (1+ display-warning-tick)))
	    (set-buffer buffer)
	    (goto-char (point-max))
	    (setq warning-count (1+ warning-count))
	    (princ (format "(%d) (%s/%s) "
			   warning-count
			   (mapconcat 'symbol-name class ",")
			   level) buffer)
	    (princ message buffer)
	    (terpri buffer)
	    (terpri buffer)))))))

(defun warn (&rest args)
  "Display a warning message.
The message is constructed by passing all args to `format'.  The message
is placed in the *Warnings* buffer, which will be popped up at the next
redisplay.  The class of the warning is `warning'.  See also
`display-warning'."
  (display-warning 'warning (apply 'format args)))

(defvar warning-marker nil)

;; When this function is called by the C code, all non-local exits are
;; trapped and C-g is inhibited; therefore, it would be a very, very
;; bad idea for this function to get into an infinite loop.

(defun display-warning-buffer ()
  "Make the buffer that contains the warnings be visible.
The C code calls this periodically, right before redisplay."
  (let ((buffer (get-buffer-create "*Warnings*")))
    (if (or (not warning-marker) (not (eq (marker-buffer warning-marker)
					  buffer)))
	(progn
	  (setq warning-marker (make-marker))
	  (set-marker warning-marker 1 buffer)))
    (set-window-start (display-buffer buffer) warning-marker)
    (set-marker warning-marker (point-max buffer) buffer)))
