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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, 2001, 2002, 2003, 2004, 2005,
4 ;; 2006, 2007 Free Software Foundation, Inc.
6 ;; Author: Howard Gayle
7 ;; Maintainer: FSF
8 ;; Keywords: hardware
10 ;; This file is part of GNU Emacs.
12 ;; GNU Emacs is free software; you can redistribute it and/or modify
13 ;; it under the terms of the GNU General Public License as published by
14 ;; the Free Software Foundation; either version 2, or (at your option)
15 ;; any later version.
17 ;; GNU Emacs is distributed in the hope that it will be useful,
18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 ;; GNU General Public License for more details.
22 ;; You should have received a copy of the GNU General Public License
23 ;; along with GNU Emacs; see the file COPYING. If not, write to the
24 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
25 ;; Boston, MA 02110-1301, USA.
27 ;;; Commentary:
29 ;;; Code:
31 (defvar led-state (make-vector 5 nil)
32 "The internal state of the LEDs. Choices are nil, t, `flash'.
33 Element 0 is not used.")
35 (defun led-flash (l)
36 "Flash LED l."
37 (aset led-state l 'flash)
38 (led-update))
40 (defun led-off (&optional l)
41 "Turn off vt100 led number L. With no argument, turn them all off."
42 (interactive "P")
43 (if l
44 (aset led-state (prefix-numeric-value l) nil)
45 (fillarray led-state nil))
46 (led-update))
48 (defun led-on (l)
49 "Turn on LED L."
50 (aset led-state l t)
51 (led-update))
53 (defun led-update ()
54 "Update the terminal's LEDs to reflect the internal state."
55 (let ((f "\e[?0") ; String to flash.
56 (o "\e[0") ; String for steady on.
57 (l 1)) ; Current LED number.
58 (while (/= l 5)
59 (let ((s (aref led-state l)))
60 (cond
61 ((eq s 'flash)
62 (setq f (concat f ";" (int-to-string l))))
64 (setq o (concat o ";" (int-to-string l))))))
65 (setq l (1+ l)))
66 (setq o (concat o "q" f "t"))
67 (send-string-to-terminal o)))
69 (provide 'vt100-led)
71 ;;; arch-tag: 346e6480-5e31-4234-aafe-257cea4a36d1
72 ;;; vt100-led.el ends here