| 1 | ;;; vt100-led.el --- functions for LED control on VT-100 terminals & clones |
| 2 | |
| 3 | ;; Copyright (C) 1988, 2001-2013 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; Author: Howard Gayle |
| 6 | ;; Maintainer: FSF |
| 7 | ;; Keywords: hardware |
| 8 | |
| 9 | ;; This file is part of GNU Emacs. |
| 10 | |
| 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 3 of the License, or |
| 14 | ;; (at your option) any later version. |
| 15 | |
| 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. |
| 20 | |
| 21 | ;; You should have received a copy of the GNU General Public License |
| 22 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
| 23 | |
| 24 | ;;; Commentary: |
| 25 | |
| 26 | ;;; Code: |
| 27 | |
| 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.") |
| 31 | |
| 32 | (defun led-flash (l) |
| 33 | "Flash LED l." |
| 34 | (aset led-state l 'flash) |
| 35 | (led-update)) |
| 36 | |
| 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)) |
| 44 | |
| 45 | (defun led-on (l) |
| 46 | "Turn on LED L." |
| 47 | (aset led-state l t) |
| 48 | (led-update)) |
| 49 | |
| 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)))) |
| 60 | (s |
| 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))) |
| 65 | |
| 66 | (provide 'vt100-led) |
| 67 | |
| 68 | ;;; vt100-led.el ends here |