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

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;; Copyright (C) 1985, 86, 87, 93, 94, 95, 96, 97, 98, 1999
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;;        Free Software Foundation, Inc.
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;; This file is part of GNU Emacs.

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

;; GNU Emacs 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
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;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
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;;; Commentary:

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

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;;; Code:
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(defgroup killing nil
  "Killing and yanking commands"
  :group 'editing)

(defgroup fill-comments nil
  "Indenting and filling of comments."
  :prefix "comment-"
  :group 'fill)

(defgroup paren-matching nil
  "Highlight (un)matching of parens and expressions."
  :group 'matching)


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(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))

;; Making and deleting lines.

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(defun newline (&optional arg)
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  "Insert a newline, and move to left margin of the new line if it's blank.
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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")
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  (barf-if-buffer-read-only)
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  ;; 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)
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		   ;; Make sure no functions want to be told about
		   ;; the range of the changes.
		   (not after-change-function)
		   (not before-change-function)
		   (not after-change-functions)
		   (not before-change-functions)
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		   ;; Make sure there are no markers here.
		   (not (buffer-has-markers-at (1- (point))))
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		   (not (buffer-has-markers-at (point)))
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		   ;; Make sure no text properties want to know
		   ;; where the change was.
		   (not (get-char-property (1- (point)) 'modification-hooks))
		   (not (get-char-property (1- (point)) 'insert-behind-hooks))
		   (or (eobp)
		       (not (get-char-property (point) 'insert-in-front-hooks)))
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		   ;; Make sure the newline before point isn't intangible.
		   (not (get-char-property (1- (point)) 'intangible))
		   ;; Make sure the newline before point isn't read-only.
		   (not (get-char-property (1- (point)) 'read-only))
		   ;; Make sure the newline before point isn't invisible.
		   (not (get-char-property (1- (point)) 'invisible))
		   ;; Make sure the newline before point has the same
		   ;; properties as the char before it (if any).
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		   (< (or (previous-property-change (point)) -2) 
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		      (- (point) 2))))
	(was-page-start (and (bolp)
			     (looking-at page-delimiter)))
	(beforepos (point)))
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    (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.
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	  ;; 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)))
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      (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))))
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    ;; Even if we did *not* get an error, keep that forward-char;
    ;; all further processing should apply to the newline that the user
    ;; thinks he inserted.

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    ;; Mark the newline(s) `hard'.
    (if use-hard-newlines
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	(set-hard-newline-properties
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	 (- (point) (if arg (prefix-numeric-value arg) 1)) (point)))
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    ;; 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))))))
    ;; 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)))
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  nil)

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(defun set-hard-newline-properties (from to)
  (let ((sticky (get-text-property from 'rear-nonsticky)))
    (put-text-property from to 'hard 't)
    ;; If rear-nonsticky is not "t", add 'hard to rear-nonsticky list
    (if (and (listp sticky) (not (memq 'hard sticky)))
	(put-text-property from (point) 'rear-nonsticky
			   (cons 'hard sticky)))))
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(defun open-line (arg)
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  "Insert a newline and leave point before it.
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If there is a fill prefix and/or a left-margin, insert them on the new line
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if the line would have been blank.
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With arg N, insert N newlines."
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  (interactive "*p")
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  (let* ((do-fill-prefix (and fill-prefix (bolp)))
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	 (do-left-margin (and (bolp) (> (current-left-margin) 0)))
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	 (loc (point)))
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    (newline arg)
    (goto-char loc)
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    (while (> arg 0)
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      (cond ((bolp)
	     (if do-left-margin (indent-to (current-left-margin)))
	     (if do-fill-prefix (insert-and-inherit fill-prefix))))
      (forward-line 1)
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      (setq arg (1- arg)))
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    (goto-char loc)
    (end-of-line)))
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(defun split-line ()
  "Split current line, moving portion beyond point vertically down."
  (interactive "*")
  (skip-chars-forward " \t")
  (let ((col (current-column))
	(pos (point)))
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    (newline 1)
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    (indent-to col 0)
    (goto-char pos)))

(defun delete-indentation (&optional arg)
  "Join this line to previous and fix up whitespace at join.
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If there is a fill prefix, delete it from the beginning of this line.
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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)))
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	;; If the second line started with the fill prefix,
	;; delete the prefix.
	(if (and fill-prefix
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		 (<= (+ (point) (length fill-prefix)) (point-max))
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		 (string= fill-prefix
			  (buffer-substring (point)
					    (+ (point) (length fill-prefix)))))
	    (delete-region (point) (+ (point) (length fill-prefix))))
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	(fixup-whitespace))))

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(defalias 'join-line #'delete-indentation) ; easier to find
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(defun delete-blank-lines ()
  "On blank line, delete all surrounding blank lines, leaving just one.
On isolated blank line, delete that one.
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On nonblank line, delete any immediately following blank lines."
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  (interactive "*")
  (let (thisblank singleblank)
    (save-excursion
      (beginning-of-line)
      (setq thisblank (looking-at "[ \t]*$"))
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      ;; Set singleblank if there is just one blank line here.
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      (setq singleblank
	    (and thisblank
		 (not (looking-at "[ \t]*\n[ \t]*$"))
		 (or (bobp)
		     (progn (forward-line -1)
			    (not (looking-at "[ \t]*$")))))))
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    ;; Delete preceding blank lines, and this one too if it's the only one.
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    (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)))))
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    ;; Delete following blank lines, unless the current line is blank
    ;; and there are no following blank lines.
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    (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))
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			   (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)))))
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(defun newline-and-indent ()
  "Insert a newline, then indent according to major mode.
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Indentation is done using the value of `indent-line-function'.
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In programming language modes, this is the same as TAB.
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In some text modes, where TAB inserts a tab, this command indents to the
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column specified by the function `current-left-margin'."
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  (interactive "*")
  (delete-region (point) (progn (skip-chars-backward " \t") (point)))
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  (newline)
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  (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,
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which means calling the current value of `indent-line-function'.
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In programming language modes, this is the same as TAB.
In some text modes, where TAB inserts a tab, this indents to the
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column specified by the function `current-left-margin'."
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  (interactive "*")
  (save-excursion
    (delete-region (point) (progn (skip-chars-backward " \t") (point)))
    (indent-according-to-mode))
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  (newline)
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  (indent-according-to-mode))
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(defun quoted-insert (arg)
  "Read next input character and insert it.
This is useful for inserting control characters.
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If the first character you type after this command is an octal digit,
you should type a sequence of octal digits which specify a character code.
Any nondigit terminates the sequence.  If the terminator is a RET,
it is discarded; any other terminator is used itself as input.
The variable `read-quoted-char-radix' specifies the radix for this feature;
set it to 10 or 16 to use decimal or hex instead of octal.
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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.
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In binary overwrite mode, this function does overwrite, and octal
digits are interpreted as a character code.  This is intended to be
useful for editing binary files."
  (interactive "*p")
  (let ((char (if (or (not overwrite-mode)
		      (eq overwrite-mode 'overwrite-mode-binary))
		  (read-quoted-char)
		(read-char))))
    ;; Assume character codes 0240 - 0377 stand for characters in some
    ;; single-byte character set, and convert them to Emacs
    ;; characters.
    (if (and enable-multibyte-characters
	     (>= char ?\240)
	     (<= char ?\377))
	(setq char (unibyte-char-to-multibyte char)))
    (if (> arg 0)
	(if (eq overwrite-mode 'overwrite-mode-binary)
	    (delete-char arg)))
    (while (> arg 0)
      (insert-and-inherit char)
      (setq arg (1- arg)))))

(defun forward-to-indentation (arg)
  "Move forward ARG lines and position at first nonblank character."
  (interactive "p")
  (forward-line arg)
  (skip-chars-forward " \t"))
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(defun backward-to-indentation (arg)
  "Move backward ARG lines and position at first nonblank character."
  (interactive "p")
  (forward-line (- arg))
  (skip-chars-forward " \t"))
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(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 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 "*")
  (skip-chars-backward " \t")
  (if (= (following-char) ? )
      (forward-char 1)
    (insert ? ))
  (delete-region (point) (progn (skip-chars-forward " \t") (point))))
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(defun beginning-of-buffer (&optional arg)
  "Move point to the beginning of the buffer; leave mark at previous position.
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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.
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Don't use this command in Lisp programs!
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\(goto-char (point-min)) is faster and avoids clobbering the mark."
  (interactive "P")
  (push-mark)
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  (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))))
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  (if arg (forward-line 1)))

(defun end-of-buffer (&optional arg)
  "Move point to the end of the buffer; leave mark at previous position.
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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.
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Don't use this command in Lisp programs!
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\(goto-char (point-max)) is faster and avoids clobbering the mark."
  (interactive "P")
  (push-mark)
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  (let ((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))))
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  ;; If we went to a place in the middle of the buffer,
  ;; adjust it to the beginning of a line.
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  (cond (arg (forward-line 1))
	((< (point) (window-end nil t))
	 ;; If the end of the buffer is not already on the screen,
	 ;; then scroll specially to put it near, but not at, the bottom.
	 (overlay-recenter (point))
	 (recenter -3))))
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(defun mark-whole-buffer ()
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  "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."
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  (interactive)
  (push-mark (point))
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  (push-mark (point-max) nil t)
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  (goto-char (point-min)))
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;; Counting lines, one way or another.

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

(defun what-line ()
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  "Print the current buffer line number and narrowed line number of point."
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  (interactive)
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  (let ((opoint (point)) start)
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    (save-excursion
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      (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)))))))))

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(defun count-lines (start end)
  "Return number of lines between START and END.
This is usually the number of newlines between them,
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but can be one more if START is not equal to END
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and the greater of them is not at the start of a line."
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  (save-excursion
    (save-restriction
      (narrow-to-region start end)
      (goto-char (point-min))
      (if (eq selective-display t)
	  (save-match-data
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	    (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)))
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	      (goto-char (point-max))
	      (if (and (/= start end)
		       (not (bolp)))
		  (1+ done)
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		done)))
	(- (buffer-size) (forward-line (buffer-size)))))))
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(defun what-cursor-position (&optional detail)
  "Print info on cursor position (on screen and within buffer).
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Also describe the character after point, and give its character code
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in octal, decimal and hex.

For a non-ASCII multibyte character, also give its encoding in the
buffer's selected coding system if the coding system encodes the
character safely.  If the character is encoded into one byte, that
code is shown in hex.  If the character is encoded into more than one
byte, just \"...\" is shown.
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With prefix argument, print additional details about that character,
instead of the cursor position.  This includes the character set name,
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the codes that identify the character within that character set.  In
addition, the encoding is fully shown."
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  (interactive "P")
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  (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))
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      (let ((coding buffer-file-coding-system)
	    encoded encoding-msg)
	(if (or (not coding)
		(eq (coding-system-type coding) t))
	    (setq coding default-buffer-file-coding-system))
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	(if (not (char-valid-p char))
	    (setq encoding-msg
		  (format "(0%o, %d, 0x%x, invalid)" char char char))
	  (setq encoded (and (>= char 128) (encode-coding-char char coding)))
	  (setq encoding-msg
		(if encoded
		    (format "(0%o, %d, 0x%x, ext %s)"
			    char char char
			    (if (and (not detail)
				     (> (length encoded) 1))
				"..."
			      (concat
			       (encoded-string-description encoded coding)
			       (if (cmpcharp char) "..." ""))))
		  (format "(0%o, %d, 0x%x)" char char char))))
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	(if detail
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	    ;; We show the detailed information of CHAR.
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	    (let ((internal
		   (if (cmpcharp char)
		       ;; For a composite character, we show the
		       ;; components only.
		       (concat "(composed \""
			       (decompose-composite-char char)
			       "\")")
		     (split-char char))))
	      (message "Char: %s %s %s"
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		       (if (< char 256)
			   (single-key-description char)
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			 (buffer-substring (point) (1+ (point))))
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		       encoding-msg internal))
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	  (if (or (/= beg 1) (/= end (1+ total)))
	      (message "Char: %s %s point=%d of %d(%d%%) <%d - %d>  column %d %s"
		       (if (< char 256)
			   (single-key-description char)
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			 (buffer-substring (point) (1+ (point))))
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		       encoding-msg pos total percent beg end col hscroll)
	    (message "Char: %s %s point=%d of %d(%d%%)  column %d %s"
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		     (if (< char 256)
			 (single-key-description char)
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		       (buffer-substring (point) (1+ (point))))
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		     encoding-msg pos total percent col hscroll)))))))
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540

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(defvar read-expression-map (cons 'keymap minibuffer-local-map)
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  "Minibuffer keymap used for reading Lisp expressions.")
(define-key read-expression-map "\M-\t" 'lisp-complete-symbol)

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(defvar read-expression-history nil)

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(defcustom eval-expression-print-level 4
  "*Value to use for `print-level' when printing value in `eval-expression'."
  :group 'lisp
  :type 'integer
  :version "21.1")

(defcustom eval-expression-print-length 12
  "*Value to use for `print-length' when printing value in `eval-expression'."
  :group 'lisp
  :type 'integer
  :version "21.1")

(defcustom eval-expression-debug-on-error t
  "*Value to use for `debug-on-error' when evaluating in `eval-expression'."
  :group 'lisp
  :type 'boolean
  :version "21.1")

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;; We define this, rather than making `eval' interactive,
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;; for the sake of completion of names like eval-region, eval-current-buffer.
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(defun eval-expression (eval-expression-arg
			&optional eval-expression-insert-value)
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  "Evaluate EXPRESSION and print value in minibuffer.
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Value is also consed on to front of the variable `values'."
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  (interactive
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   (list (read-from-minibuffer "Eval: "
			       nil read-expression-map t
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			       'read-expression-history)
	 current-prefix-arg))
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  (let ((debug-on-error eval-expression-debug-on-error))
    (setq values (cons (eval eval-expression-arg) values)))
  (let ((print-length eval-expression-print-length)
	(print-level eval-expression-print-level))
    (prin1 (car values)
	   (if eval-expression-insert-value (current-buffer) t))))
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(defun edit-and-eval-command (prompt command)
  "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."
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  (let ((command (read-from-minibuffer prompt
				       (prin1-to-string command)
				       read-expression-map t
				       '(command-history . 1))))
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    ;; If command was added to command-history as a string,
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    ;; get rid of that.  We want only evaluable expressions there.
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    (if (stringp (car command-history))
	(setq command-history (cdr command-history)))

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

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(defun repeat-complex-command (arg)
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  "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.
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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."
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  (interactive "p")
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  (let ((elt (nth (1- arg) command-history))
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	newcmd)
    (if elt
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	(progn
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	  (setq newcmd
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		(let ((print-level nil)
		      (minibuffer-history-position arg)
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		      (minibuffer-history-sexp-flag (1+ (minibuffer-depth))))
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		  (read-from-minibuffer
		   "Redo: " (prin1-to-string elt) read-expression-map t
		   (cons 'command-history arg))))
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	  ;; If command was added to command-history as a string,
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	  ;; get rid of that.  We want only evaluable expressions there.
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	  (if (stringp (car command-history))
	      (setq command-history (cdr command-history)))

	  ;; If command to be redone does not match front of history,
	  ;; add it to the history.
	  (or (equal newcmd (car command-history))
	      (setq command-history (cons newcmd command-history)))
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	  (eval newcmd))
      (ding))))
635

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(defvar minibuffer-history nil
  "Default minibuffer history list.
This is used for all minibuffer input
except when an alternate history list is specified.")
(defvar minibuffer-history-sexp-flag nil
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  "Non-nil when doing history operations on `command-history'.
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More generally, indicates that the history list being acted on
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contains expressions rather than strings.
It is only valid if its value equals the current minibuffer depth,
to handle recursive uses of the minibuffer.")
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(setq minibuffer-history-variable 'minibuffer-history)
(setq minibuffer-history-position nil)
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(defvar minibuffer-history-search-history nil)
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(mapcar
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 (lambda (key-and-command)
   (mapcar
    (lambda (keymap-and-completionp)
      ;; Arg is (KEYMAP-SYMBOL . COMPLETION-MAP-P).
      ;; If the cdr of KEY-AND-COMMAND (the command) is a cons,
      ;; its car is used if COMPLETION-MAP-P is nil, its cdr if it is t.
      (define-key (symbol-value (car keymap-and-completionp))
	(car key-and-command)
	(let ((command (cdr key-and-command)))
	  (if (consp command)
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	      ;; (and ... nil) => ... turns back on the completion-oriented
	      ;; history commands which rms turned off since they seem to
	      ;; do things he doesn't like.
	      (if (and (cdr keymap-and-completionp) nil) ;XXX turned off
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		  (progn (error "EMACS BUG!") (cdr command))
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		(car command))
	    command))))
    '((minibuffer-local-map . nil)
      (minibuffer-local-ns-map . nil)
      (minibuffer-local-completion-map . t)
      (minibuffer-local-must-match-map . t)
      (read-expression-map . nil))))
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 '(("\en" . (next-history-element . next-complete-history-element))
   ([next] . (next-history-element . next-complete-history-element))
   ("\ep" . (previous-history-element . previous-complete-history-element))
   ([prior] . (previous-history-element . previous-complete-history-element))
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   ("\er" . previous-matching-history-element)
   ("\es" . next-matching-history-element)))
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(defvar minibuffer-text-before-history nil
  "Text that was in this minibuffer before any history commands.
This is nil if there have not yet been any history commands
in this use of the minibuffer.")

(add-hook 'minibuffer-setup-hook 'minibuffer-history-initialize)

(defun minibuffer-history-initialize ()
  (setq minibuffer-text-before-history nil))

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(defcustom minibuffer-history-case-insensitive-variables nil
  "*Minibuffer history variables for which matching should ignore case.
If a history variable is a member of this list, then the
\\[previous-matching-history-element] and \\[next-matching-history-element]\
 commands ignore case when searching it, regardless of `case-fold-search'."
  :type '(repeat variable)
  :group 'minibuffer)

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(defun previous-matching-history-element (regexp n)
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  "Find the previous history element that matches REGEXP.
\(Previous history elements refer to earlier actions.)
With prefix argument N, search for Nth previous match.
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If N is negative, find the next or Nth next match.
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An uppercase letter in REGEXP makes the search case-sensitive.
See also `minibuffer-history-case-insensitive-variables'."
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  (interactive
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   (let* ((enable-recursive-minibuffers t)
	  (regexp (read-from-minibuffer "Previous element matching (regexp): "
					nil
					minibuffer-local-map
					nil
					'minibuffer-history-search-history)))
     ;; Use the last regexp specified, by default, if input is empty.
     (list (if (string= regexp "")
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	       (if minibuffer-history-search-history
		   (car minibuffer-history-search-history)
		 (error "No previous history search regexp"))
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	     regexp)
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	   (prefix-numeric-value current-prefix-arg))))
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  (if (and (zerop minibuffer-history-position)
	   (null minibuffer-text-before-history))
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      (setq minibuffer-text-before-history (field-string (point-max))))
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  (let ((history (symbol-value minibuffer-history-variable))
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	(case-fold-search
	 (if (isearch-no-upper-case-p regexp t)	; assume isearch.el is dumped
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	     ;; On some systems, ignore case for file names.
	     (if (memq minibuffer-history-variable
		       minibuffer-history-case-insensitive-variables)
		 t
	       ;; Respect the user's setting for case-fold-search:
	       case-fold-search)
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	   nil))
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	prevpos
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	(pos minibuffer-history-position))
    (while (/= n 0)
      (setq prevpos pos)
      (setq pos (min (max 1 (+ pos (if (< n 0) -1 1))) (length history)))
      (if (= pos prevpos)
	  (error (if (= pos 1)
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		     "No later matching history item"
		   "No earlier matching history item")))
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      (if (string-match regexp
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			(if (eq minibuffer-history-sexp-flag
				(minibuffer-depth))
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			    (let ((print-level nil))
			      (prin1-to-string (nth (1- pos) history)))
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			  (nth (1- pos) history)))
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	  (setq n (+ n (if (< n 0) 1 -1)))))
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    (setq minibuffer-history-position pos)
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    (goto-char (point-max))
    (erase-field)
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    (let ((elt (nth (1- pos) history)))
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      (insert (if (eq minibuffer-history-sexp-flag (minibuffer-depth))
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		  (let ((print-level nil))
		    (prin1-to-string elt))
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		elt)))
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      (goto-char (field-beginning)))
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  (if (or (eq (car (car command-history)) 'previous-matching-history-element)
	  (eq (car (car command-history)) 'next-matching-history-element))
      (setq command-history (cdr command-history))))
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(defun next-matching-history-element (regexp n)
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  "Find the next history element that matches REGEXP.
\(The next history element refers to a more recent action.)
With prefix argument N, search for Nth next match.
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If N is negative, find the previous or Nth previous match.
An uppercase letter in REGEXP makes the search case-sensitive."
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  (interactive
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   (let* ((enable-recursive-minibuffers t)
	  (regexp (read-from-minibuffer "Next element matching (regexp): "
					nil
					minibuffer-local-map
					nil
					'minibuffer-history-search-history)))
     ;; Use the last regexp specified, by default, if input is empty.
     (list (if (string= regexp "")
	       (setcar minibuffer-history-search-history
		       (nth 1 minibuffer-history-search-history))
	     regexp)
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	   (prefix-numeric-value current-prefix-arg))))
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  (previous-matching-history-element regexp (- n)))
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(defun next-history-element (n)
  "Insert the next element of the minibuffer history into the minibuffer."
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  (interactive "p")
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  (or (zerop n)
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      (let ((narg (- minibuffer-history-position n))
	    (minimum (if minibuffer-default -1 0))
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	    elt minibuffer-returned-to-present)
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	(if (and (zerop minibuffer-history-position)
		 (null minibuffer-text-before-history))
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	    (setq minibuffer-text-before-history (field-string (point-max))))
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	(if (< narg minimum)
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	    (if minibuffer-default
		(error "End of history; no next item")
	      (error "End of history; no default available")))
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	(if (> narg (length (symbol-value minibuffer-history-variable)))
	    (error "Beginning of history; no preceding item"))
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	(goto-char (point-max))
	(erase-field)
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	(setq minibuffer-history-position narg)
	(cond ((= narg -1)
	       (setq elt minibuffer-default))
	      ((= narg 0)
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	       (setq elt (or minibuffer-text-before-history ""))
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	       (setq minibuffer-returned-to-present t)
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	       (setq minibuffer-text-before-history nil))
	      (t (setq elt (nth (1- minibuffer-history-position)
				(symbol-value minibuffer-history-variable)))))
	(insert
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	 (if (and (eq minibuffer-history-sexp-flag (minibuffer-depth))
		  (not minibuffer-returned-to-present))
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	     (let ((print-level nil))
	       (prin1-to-string elt))
	   elt))
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	(goto-char (field-beginning)))))
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(defun previous-history-element (n)
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  "Inserts the previous element of the minibuffer history into the minibuffer."
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  (interactive "p")
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  (next-history-element (- n)))
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(defun next-complete-history-element (n)
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  "Get next history element which completes the minibuffer before the point.
The contents of the minibuffer after the point are deleted, and replaced
by the new completion."
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  (interactive "p")
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  (let ((point-at-start (point)))
    (next-matching-history-element
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     (concat
      "^" (regexp-quote (buffer-substring (field-beginning) (point))))
     n)
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    ;; next-matching-history-element always puts us at (point-min).
    ;; Move to the position we were at before changing the buffer contents.
    ;; This is still sensical, because the text before point has not changed.
    (goto-char point-at-start)))
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(defun previous-complete-history-element (n)
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  "\
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Get previous history element which completes the minibuffer before the point.
The contents of the minibuffer after the point are deleted, and replaced
by the new completion."
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  (interactive "p")
  (next-complete-history-element (- n)))
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;; These two functions are for compatibility with the old subrs of the
;; same name.

(defun minibuffer-prompt-width ()
  "Return the display width of the minibuffer prompt.
Return 0 if current buffer is not a mini-buffer."
  ;; Return the width of everything before the field at the end of
  ;; the buffer; this should be 0 for normal buffers.
  (1- (field-beginning (point-max))))

(defun minibuffer-prompt-end ()
  "Return the buffer position of the end of the minibuffer prompt.
Return 0 if current buffer is not a mini-buffer."
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  (field-beginning (point-max)))

860

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;Put this on C-x u, so we can force that rather than C-_ into startup msg
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(defalias 'advertised-undo 'undo)
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(defun undo (&optional arg)
  "Undo some previous changes.
Repeat this command to undo more changes.
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A numeric argument serves as a repeat count.

Just C-u as argument requests selective undo,
limited to changes within the current region.
Likewise in Transient Mark mode when the mark is active."
  (interactive "*P")
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  ;; If we don't get all the way thru, make last-command indicate that
  ;; for the following command.
  (setq this-command t)
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  (let ((modified (buffer-modified-p))
	(recent-save (recent-auto-save-p)))
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    (or (eq (selected-window) (minibuffer-window))
	(message "Undo!"))
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    (or (eq last-command 'undo)
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	(progn (if (or arg (and transient-mark-mode mark-active))
		   (undo-start (region-beginning) (region-end))
		 (undo-start))
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	       (undo-more 1)))
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    (undo-more (if arg (prefix-numeric-value arg) 1))
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    ;; 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))))
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    (and modified (not (buffer-modified-p))
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	 (delete-auto-save-file-if-necessary recent-save)))
  ;; If we do get all the way thru, make this-command indicate that.
  (setq this-command 'undo))
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(defvar pending-undo-list nil
  "Within a run of consecutive undo commands, list remaining to be undone.")

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(defvar undo-in-progress nil
  "Non-nil while performing an undo.
Some change-hooks test this variable to do something different.")

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(defun undo-more (count)
  "Undo back N undo-boundaries beyond what was already undone recently.
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Call `undo-start' to get ready to undo recent changes,
then call `undo-more' one or more times to undo them."
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  (or pending-undo-list
      (error "No further undo information"))
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  (let ((undo-in-progress t))
    (setq pending-undo-list (primitive-undo count pending-undo-list))))
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;; Deep copy of a list
(defun undo-copy-list (list)
  "Make a copy of undo list LIST."
  (mapcar 'undo-copy-list-1 list))

(defun undo-copy-list-1 (elt)
  (if (consp elt)
      (cons (car elt) (undo-copy-list-1 (cdr elt)))
    elt))

(defun undo-start (&optional beg end)
  "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 BEG and END are specified, then only undo elements
that apply to text between BEG and END are used; other undo elements
are ignored.  If BEG and END are nil, all undo elements are used."
  (if (eq buffer-undo-list t)
      (error "No undo information in this buffer"))
  (setq pending-undo-list 
	(if (and beg end (not (= beg end)))
	    (undo-make-selective-list (min beg end) (max beg end))
	  buffer-undo-list)))

(defvar undo-adjusted-markers)

(defun undo-make-selective-list (start end)
  "Return a list of undo elements for the region START to END.
The elements come from `buffer-undo-list', but we keep only
the elements inside this region, and discard those outside this region.
If we find an element that crosses an edge of this region,
we stop and ignore all further elements."
  (let ((undo-list-copy (undo-copy-list buffer-undo-list))
	(undo-list (list nil))
	undo-adjusted-markers
	some-rejected
	undo-elt undo-elt temp-undo-list delta)
    (while undo-list-copy
      (setq undo-elt (car undo-list-copy))
      (let ((keep-this
	     (cond ((and (consp undo-elt) (eq (car undo-elt) t))
		    ;; This is a "was unmodified" element.
		    ;; Keep it if we have kept everything thus far.
		    (not some-rejected))
		   (t
		    (undo-elt-in-region undo-elt start end)))))
	(if keep-this
	    (progn
	      (setq end (+ end (cdr (undo-delta undo-elt))))
	      ;; Don't put two nils together in the list
	      (if (not (and (eq (car undo-list) nil)
			    (eq undo-elt nil)))
		  (setq undo-list (cons undo-elt undo-list))))
	  (if (undo-elt-crosses-region undo-elt start end)
	      (setq undo-list-copy nil)
	    (setq some-rejected t)
	    (setq temp-undo-list (cdr undo-list-copy))
	    (setq delta (undo-delta undo-elt))

	    (when (/= (cdr delta) 0)
	      (let ((position (car delta))
		    (offset (cdr delta)))

		;; Loop down the earlier events adjusting their buffer positions
		;; to reflect the fact that a change to the buffer isn't being
		;; undone. We only need to process those element types which
		;; undo-elt-in-region will return as being in the region since
		;; only those types can ever get into the output

		(while temp-undo-list
		  (setq undo-elt (car temp-undo-list))
		  (cond ((integerp undo-elt)
			 (if (>= undo-elt position)
			     (setcar temp-undo-list (- undo-elt offset))))
			((atom undo-elt) nil)
			((stringp (car undo-elt))
			 ;; (TEXT . POSITION)
			 (let ((text-pos (abs (cdr undo-elt)))
			       (point-at-end (< (cdr undo-elt) 0 )))
			   (if (>= text-pos position)
			       (setcdr undo-elt (* (if point-at-end -1 1) 
						   (- text-pos offset))))))
			((integerp (car undo-elt))
			 ;; (BEGIN . END)
			 (when (>= (car undo-elt) position)
			   (setcar undo-elt (- (car undo-elt) offset))
			   (setcdr undo-elt (- (cdr undo-elt) offset))))
			((null (car undo-elt))
			 ;; (nil PROPERTY VALUE BEG . END)
			 (let ((tail (nthcdr 3 undo-elt)))
			   (when (>= (car tail) position)
			     (setcar tail (- (car tail) offset))
			     (setcdr tail (- (cdr tail) offset))))))
		  (setq temp-undo-list (cdr temp-undo-list))))))))
      (setq undo-list-copy (cdr undo-list-copy)))
    (nreverse undo-list)))

(defun undo-elt-in-region (undo-elt start end)
  "Determine whether UNDO-ELT falls inside the region START ... END.
If it crosses the edge, we return nil."
  (cond ((integerp undo-elt)
	 (and (>= undo-elt start)
	      (<  undo-elt end)))
	((eq undo-elt nil)
	 t)
	((atom undo-elt)
	 nil)
	((stringp (car undo-elt))
	 ;; (TEXT . POSITION)
	 (and (>= (abs (cdr undo-elt)) start)
	      (< (abs (cdr undo-elt)) end)))
	((and (consp undo-elt) (markerp (car undo-elt)))
	 ;; This is a marker-adjustment element (MARKER . ADJUSTMENT).
	 ;; See if MARKER is inside the region.
	 (let ((alist-elt (assq (car undo-elt) undo-adjusted-markers)))
	   (unless alist-elt
	     (setq alist-elt (cons (car undo-elt)
				   (marker-position (car undo-elt))))
	     (setq undo-adjusted-markers
		   (cons alist-elt undo-adjusted-markers)))
	   (and (cdr alist-elt)
		(>= (cdr alist-elt) start)
		(< (cdr alist-elt) end))))
	((null (car undo-elt))
	 ;; (nil PROPERTY VALUE BEG . END)
	 (let ((tail (nthcdr 3 undo-elt)))
	   (and (>= (car tail) start)
		(< (cdr tail) end))))
	((integerp (car undo-elt))
	 ;; (BEGIN . END)
	 (and (>= (car undo-elt) start)
	      (< (cdr undo-elt) end)))))

(defun undo-elt-crosses-region (undo-elt start end)
  "Test whether UNDO-ELT crosses one edge of that region START ... END.
This assumes we have already decided that UNDO-ELT
is not *inside* the region START...END."
  (cond ((atom undo-elt) nil)
	((null (car undo-elt))
	 ;; (nil PROPERTY VALUE BEG . END)
	 (let ((tail (nthcdr 3 undo-elt)))
	   (not (or (< (car tail) end)
		    (> (cdr tail) start)))))
	((integerp (car undo-elt))
	 ;; (BEGIN . END)
	 (not (or (< (car undo-elt) end)
		  (> (cdr undo-elt) start))))))

;; Return the first affected buffer position and the delta for an undo element
;; delta is defined as the change in subsequent buffer positions if we *did*
;; the undo.
(defun undo-delta (undo-elt)
  (if (consp undo-elt)
      (cond ((stringp (car undo-elt))
	     ;; (TEXT . POSITION)
	     (cons (abs (cdr undo-elt)) (length (car undo-elt))))
	    ((integerp (car undo-elt))
	     ;; (BEGIN . END)
	     (cons (car undo-elt) (- (car undo-elt) (cdr undo-elt))))
	    (t
	     '(0 . 0)))
    '(0 . 0)))

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(defvar shell-command-history nil
  "History list for some commands that read shell commands.")

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(defvar shell-command-switch "-c"
  "Switch used to have the shell execute its command line argument.")

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(defvar shell-command-default-error-buffer nil
  "*Buffer name for `shell-command' and `shell-command-on-region' error output.
This buffer is used when `shell-command' or 'shell-command-on-region'
is run interactively.  A value of nil means that output to stderr and
stdout will be intermixed in the output stream.")

(defun shell-command (command &optional output-buffer error-buffer)
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  "Execute string COMMAND in inferior shell; display output, if any.
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If COMMAND ends in ampersand, execute it asynchronously.
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The output appears in the buffer `*Async Shell Command*'.
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That buffer is in shell mode.
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Otherwise, COMMAND is executed synchronously.  The output appears in the
buffer `*Shell Command Output*'.
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If the output is one line, it is displayed in the echo area *as well*,
but it is nonetheless available in buffer `*Shell Command Output*',
even though that buffer is not automatically displayed.
If there is no output, or if output is inserted in the current buffer,
then `*Shell Command Output*' is deleted.
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To specify a coding system for converting non-ASCII characters
in the shell command output, use \\[universal-coding-system-argument]
before this command.

Noninteractive callers can specify coding systems by binding
`coding-system-for-read' and `coding-system-for-write'.

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The optional second argument OUTPUT-BUFFER, if non-nil,
says to put the output in some other buffer.
If OUTPUT-BUFFER is a buffer or buffer name, put the output there.
If OUTPUT-BUFFER is not a buffer and not nil,
insert output in current buffer.  (This cannot be done asynchronously.)
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