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emacs/lisp/vt100-led.el
2005-08-06 22:13:43 +00:00

72 lines
2.0 KiB
EmacsLisp

;;; vt100-led.el --- functions for LED control on VT-100 terminals & clones
;; Copyright (C) 1988, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
;; Author: Howard Gayle
;; Maintainer: FSF
;; Keywords: hardware
;; 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., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;;; Commentary:
;;; Code:
(defvar led-state (make-vector 5 nil)
"The internal state of the LEDs. Choices are nil, t, `flash.
Element 0 is not used.")
(defun led-flash (l)
"Flash LED l."
(aset led-state l 'flash)
(led-update))
(defun led-off (&optional l)
"Turn off vt100 led number L. With no argument, turn them all off."
(interactive "P")
(if l
(aset led-state (prefix-numeric-value l) nil)
(fillarray led-state nil))
(led-update))
(defun led-on (l)
"Turn on LED l."
(aset led-state l t)
(led-update))
(defun led-update ()
"Update the terminal's LEDs to reflect the internal state."
(let ((f "\e[?0") ; String to flash.
(o "\e[0") ; String for steady on.
(l 1)) ; Current LED number.
(while (/= l 5)
(let ((s (aref led-state l)))
(cond
((eq s 'flash)
(setq f (concat f ";" (int-to-string l))))
(s
(setq o (concat o ";" (int-to-string l))))))
(setq l (1+ l)))
(setq o (concat o "q" f "t"))
(send-string-to-terminal o)))
(provide 'vt100-led)
;;; arch-tag: 346e6480-5e31-4234-aafe-257cea4a36d1
;;; vt100-led.el ends here