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124 lines
4.7 KiB
EmacsLisp
124 lines
4.7 KiB
EmacsLisp
;;; flow-ctrl.el --- help for lusers on cu(1) or ttys with wired-in ^S/^Q flow control
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;;; Copyright (C) 1990, 1991, 1994 Free Software Foundation, Inc.
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;; Author Kevin Gallagher
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;; Maintainer: FSF
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;; Adapted-By: ESR
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;; Keywords: hardware
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to
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;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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;;; Commentary:
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;;;; Terminals that use XON/XOFF flow control can cause problems with
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;;;; GNU Emacs users. This file contains Emacs Lisp code that makes it
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;;;; easy for a user to deal with this problem, when using such a
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;;;; terminal.
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;;;;
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;;;; To invoke these adjustments, a user need only invoke the function
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;;;; enable-flow-control-on with a list of terminal types in his/her own
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;;;; .emacs file. As arguments, give it the names of one or more terminal
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;;;; types in use by that user which require flow control adjustments.
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;;;; Here's an example:
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;;;;
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;;;; (enable-flow-control-on "vt200" "vt300" "vt101" "vt131")
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;;; Portability note: This uses (getenv "TERM"), and therefore probably
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;;; won't work outside of UNIX-like environments.
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;;; Code:
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(defvar flow-control-c-s-replacement ?\034
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"Character that replaces C-s, when flow control handling is enabled.")
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(defvar flow-control-c-q-replacement ?\036
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"Character that replaces C-q, when flow control handling is enabled.")
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;;;###autoload
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(defun enable-flow-control (&optional argument)
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"Toggle flow control handling.
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When handling is enabled, user can type C-s as C-\\, and C-q as C-^.
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With arg, enable flow control mode if arg is positive, otherwise disable."
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(interactive "P")
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(if (if argument
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;; Argument means enable if arg is positive.
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(<= (prefix-numeric-value argument) 0)
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;; No arg means toggle.
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(nth 1 (current-input-mode)))
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(progn
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;; Turn flow control off, and stop exchanging chars.
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(set-input-mode t nil (nth 2 (current-input-mode)))
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(if keyboard-translate-table
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(progn
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(aset keyboard-translate-table flow-control-c-s-replacement
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flow-control-c-s-replacement)
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(aset keyboard-translate-table ?\^s ?\^s)
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(aset keyboard-translate-table flow-control-c-q-replacement
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flow-control-c-q-replacement)
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(aset keyboard-translate-table ?\^q ?\^q))))
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;; Turn flow control on.
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;; Tell emacs to pass C-s and C-q to OS.
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(set-input-mode nil t (nth 2 (current-input-mode)))
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;; Initialize translate table, saving previous mappings, if any.
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(let ((the-table (make-string (max 128 (length keyboard-translate-table))
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0)))
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(let ((i 0)
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(j (length keyboard-translate-table)))
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(while (< i j)
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(aset the-table i (elt keyboard-translate-table i))
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(setq i (1+ i)))
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(while (< i 128)
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(aset the-table i i)
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(setq i (1+ i))))
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(setq keyboard-translate-table the-table))
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;; Swap C-s and C-\
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(aset keyboard-translate-table flow-control-c-s-replacement ?\^s)
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(aset keyboard-translate-table ?\^s flow-control-c-s-replacement)
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;; Swap C-q and C-^
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(aset keyboard-translate-table flow-control-c-q-replacement ?\^q)
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(aset keyboard-translate-table ?\^q flow-control-c-q-replacement)
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(message (concat
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"XON/XOFF adjustment for "
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(getenv "TERM")
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": use "
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(single-key-description flow-control-c-s-replacement)
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" for C-s, and use "
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(single-key-description flow-control-c-q-replacement)
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" for C-q"))
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(sleep-for 2))) ; Give user a chance to see message.
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;;;###autoload
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(defun enable-flow-control-on (&rest losing-terminal-types)
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"Enable flow control if using one of a specified set of terminal types.
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Use `(enable-flow-control-on \"vt100\" \"h19\")' to enable flow control
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on VT-100 and H19 terminals. When flow control is enabled,
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you must type C-\\ to get the effect of a C-s, and type C-^
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to get the effect of a C-q."
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(let ((term (getenv "TERM"))
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hyphend)
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(if term
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(progn
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;; Strip off hyphen and what follows
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(while (setq hyphend (string-match "[-_][^-_]+$" term))
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(setq term (substring term 0 hyphend)))
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(and (member term losing-terminal-types)
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(enable-flow-control))))))
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(provide 'flow-ctrl)
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;;; flow-ctrl.el ends here
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