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[emacs.git] / lisp / vt100-led.el
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1 ;;; vt100-led.el --- functions for LED control on VT-100 terminals & clones.
3 ;; Copyright (C) 1988 Free Software Foundation, Inc.
5 ;; Author: Howard Gayle
6 ;; Maintainer: FSF
7 ;; Keywords: hardware
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software; you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation; either version 2, or (at your option)
14 ;; any later version.
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; see the file COPYING. If not, write to the
23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
24 ;; Boston, MA 02111-1307, USA.
26 ;;; Code:
28 (defvar led-state (make-vector 5 nil)
29 "The internal state of the LEDs. Choices are nil, t, `flash.
30 Element 0 is not used.")
32 (defun led-flash (l)
33 "Flash LED l."
34 (aset led-state l 'flash)
35 (led-update))
37 (defun led-off (&optional l)
38 "Turn off vt100 led number L. With no argument, turn them all off."
39 (interactive "P")
40 (if l
41 (aset led-state (prefix-numeric-value l) nil)
42 (fillarray led-state nil))
43 (led-update))
45 (defun led-on (l)
46 "Turn on LED l."
47 (aset led-state l t)
48 (led-update))
50 (defun led-update ()
51 "Update the terminal's LEDs to reflect the internal state."
52 (let ((f "\e[?0") ; String to flash.
53 (o "\e[0") ; String for steady on.
54 (l 1)) ; Current LED number.
55 (while (/= l 5)
56 (let ((s (aref led-state l)))
57 (cond
58 ((eq s 'flash)
59 (setq f (concat f ";" (int-to-string l))))
61 (setq o (concat o ";" (int-to-string l))))))
62 (setq l (1+ l)))
63 (setq o (concat o "q" f "t"))
64 (send-string-to-terminal o)))
66 (provide 'vt100-led)
68 ;;; vt100-led.el ends here