--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lisp/emulators/scroll-lock.el	Mon Aug 13 08:54:01 2007 +0200
@@ -0,0 +1,137 @@
+;; @(#) scroll-lock.el -- scroll-locking minor mode
+
+;; Authors:
+;;    Gary D. Foster <Gary.Foster@corp.sun.com>
+;; with contributions/suggestions/ideas from:
+;;    Rick Macdonald <rickm@vsl.com>
+;;    Anders Lindgren <andersl@csd.uu.se>
+;; $Revision: 1.1 $
+;; Keywords: scroll crisp brief lock
+
+;; 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
+;; the Free Software Foundation; either version 2, or (at your option)
+;; 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
+;; 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.
+
+;; Commentary
+;;    This mode allows multiple buffers to be 'locked' so that scrolling
+;;    up or down lines in any buffer causes all the buffers to mirror
+;;    the scrolling.  It hooks into the post-command-hook to check for
+;;    potential scrolling commands and if we're locked, mirrors them in all
+;;    windows.	This allows us to grab line-at-a-time scrolling as well as
+;;    screen-at-a-time scrolling, and doesn't remap any of the keyboard
+;;    commands to do it.
+
+;; This minor mode is normally autoloaded from the scroll-lock package.
+;; You can disable autoloading of this package by placing
+;; (setq crisp-load-scroll-lock nil) in your .emacs before loading
+;; the crisp package.  If you want to use this package by itself,
+;; you can enable it by placing the following in your .emacs:
+
+;; (require 'scroll-lock)
+
+;; In the first (autoloaded) case, meta-f1 is bound to the command to
+;; toggle the scroll-lock mode.  In the second (non-autoloaded) case,
+;; you can enable and disable it with the 'scroll-lock-mode' command.
+
+(defvar scroll-lock-running-xemacs (string-match "XEmacs\\|Lucid" emacs-version))
+
+(defvar scroll-lock-modeline-string " *SL*"
+  "String to display in the modeline when Scroll Lock mode is enabled.")
+
+(defvar scroll-lock-is-locked nil
+  "Track status of scroll locking.")
+(if scroll-lock-running-xemacs
+    (add-minor-mode 'scroll-lock-is-locked scroll-lock-modeline-string)
+  (or (assq 'scroll-lock-is-locked minor-mode-alist)
+      (setq minor-mode-alist
+	    (cons '(scroll-lock-is-locked scroll-lock-modeline-string) minor-mode-alist))))
+
+(defun scroll-lock-scroll-down-all (arg)
+  "Scroll-down all visible windows."
+  (interactive "P")
+  (let ((num-windows (count-windows))
+	(count 1))
+    (if (> num-windows 1)
+	( progn (other-window 1)
+		(while (< count num-windows)
+		  (if (not (eq (point) (point-max)))
+		      (progn (call-interactively 'next-line)))
+		  (other-window 1)
+		  (setq count (1+ count)))))))
+
+(defun scroll-lock-scroll-up-all (arg)
+  "Scroll-up all visible windows."
+  (interactive "P")
+  (let ((num-windows (count-windows))
+	(count 1))
+    (if (> num-windows 1)
+	( progn (other-window 1)
+		(while (< count num-windows)
+		  (if (not (eq (point) (point-min)))
+		      (progn (call-interactively 'previous-line)))
+		  (other-window 1)
+		  (setq count (1+ count)))))))
+
+(defun scroll-lock-page-down-all (arg)
+  "Page-down all visible windows."
+  (interactive "P")
+  (let ((num-windows (count-windows))
+	(count 1))
+    (if (> num-windows 1)
+	(progn (other-window 1)
+	       (while (< count num-windows)
+		 (call-interactively 'fkey-scroll-up)
+		 (other-window 1)
+		 (setq count (1+ count)))))))
+
+(defun scroll-lock-page-up-all (arg)
+  "Page-up all visible windows."
+  (interactive "P")
+  (let ((num-windows (count-windows))
+	(count 1))
+    (if (> num-windows 1)
+	(progn (other-window 1)
+	       (while (< count num-windows)
+		 (call-interactively 'fkey-scroll-down)
+		 (other-window 1)
+		 (setq count (1+ count)))))))
+
+
+(defun scroll-lock-check-to-scroll ()
+  "Check last-command to see if a scroll was done."
+  (if (eq this-command 'next-line)
+      (call-interactively 'scroll-lock-scroll-down-all))
+  (if (eq this-command 'previous-line)
+      (call-interactively 'scroll-lock-scroll-up-all))
+  (if (eq this-command 'fkey-scroll-up)
+      (call-interactively 'scroll-lock-page-down-all))
+  (if (eq this-command 'fkey-scroll-down)
+      (call-interactively 'scroll-lock-page-up-all)))
+
+
+(defun scroll-lock-mode (arg)
+  "Toggle scroll-lock minor mode."
+  (interactive "P")
+  (setq scroll-lock-is-locked (not scroll-lock-is-locked))
+  (cond
+   ((eq scroll-lock-is-locked 't)
+    (add-hook 'post-command-hook 'scroll-lock-check-to-scroll))
+   ((eq scroll-lock-is-locked 'nil)
+    (remove-hook 'post-command-hook 'scroll-lock-check-to-scroll))))
+
+(provide 'scroll-lock)
+
+;;; scroll-lock.el ends here