lisp/double.el

   1 ;;; double.el - Support for keyboard remapping with double clicking.
   2
   3 ;; Copyright (C) 1994 Free Software Foundation, Inc.
   4
   5 ;; Author: Per Abrahamsen <abraham@iesd.auc.dk>
   6 ;; Keywords: i18n
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  23
  24 ;;; Commentary:
  25
  26 ;; This mode is intended for use with languages that adds a small
  27 ;; number of extra letters not available on the keyboard.
  28 ;;
  29 ;; Examples includes Scandinavian and German with an US keyboard.
  30 ;;
  31 ;; The idea is that certain keys are overloaded.  When you press it
  32 ;; once it will insert one string, and when you press it twice the
  33 ;; string will be replaced by another.  This can be used for mapping
  34 ;; keys on a US keyboard to generate characters according to the local
  35 ;; keyboard convention when pressed once, and according to US keyboard
  36 ;; convetion when pressed twice.
  37 ;;
  38 ;; To use this mode, you must define the variable `double-map' and
  39 ;; then enable double mode with `M-x double-mode'.  Read the
  40 ;; documentation for both of them.
  41 ;;
  42 ;; The default mapping is for getting Danish/Norwegian keyboard layout
  43 ;; using ISO Latin 1 on a US keyboard.
  44 ;;
  45 ;; Requires FSF Emacs 19.20 or later.
  46 ;;
  47 ;; Imprtant node: While I would like to hear comments, bug reports,
  48 ;; suggestions, please do @strong{not} expect me to put other mappings
  49 ;; that the default into this file.  There are billions and billions
  50 ;; of such mappings, and just supporting the most common would
  51 ;; increase the size of this nice small file manyfold.
  52
  53 ;;; ChangeLog:
  54
  55 ;; * 1994-02-03         Per Abrahamsen
  56 ;;      Created.
  57
  58 ;;; Code:
  59
  60 (defvar double-map
  61   '((?\; "\346" ";")
  62     (?\' "\370" "'")
  63     (?\[ "\345" "[")
  64     (?\: "\306" ":")
  65     (?\" "\330" "\"")
  66     (?\{ "\305" "{"))
  67   "Alist of key translations activated by double mode.
  68
  69 Each entry is a list with three elements:
  70 1. The key activating the translation.
  71 2. The string to be inserted when the key is pressed once.
  72 3. The string to be inserted when the key is pressed twice.")
  73
  74 ;;; Read Event
  75
  76 (defvar double-last-event nil)
  77 ;; The last key that generated a double key event.
  78
  79 (defun double-read-event (prompt)
  80   ;; Read an event
  81   (if isearch-mode (isearch-update))
  82   (if prompt
  83       (prog2 (message "%s%c" prompt double-last-event)
  84           (read-event)
  85         (message ""))
  86     (read-event)))
  87
  88 (global-set-key [ignore] '(lambda () (interactive)))
  89
  90 (or (boundp 'isearch-mode-map)
  91     (load-library "isearch"))
  92
  93 (define-key isearch-mode-map [ignore]
  94   (function (lambda () (interactive) (isearch-update))))
  95
  96 (defun double-translate-key (prompt)
  97   ;; Translate input events using double map.
  98   (let ((key last-input-char))
  99     (cond (unread-command-events
 100            ;; Artificial event, ignore it.
 101            (vector key))
 102           ((eq key 'magic-start)
 103            ;; End of generated event.  See if he will repeat it...
 104            (let ((new (double-read-event prompt))
 105                  (entry (assoc double-last-event double-map)))
 106              (if (eq new double-last-event)
 107                  (progn
 108                    (setq unread-command-events
 109                          (append (make-list (1- (length (nth 1 entry)))
 110                                             127)
 111                                  (nth 2 entry)
 112                                  '(magic-end)))
 113                    (vector 127))
 114                (setq unread-command-events (list new))
 115                [ignore])))
 116           ((eq key 'magic-end)
 117            ;; End of double event.  Ignore.
 118            [ignore])
 119           (t
 120            ;; New key.
 121            (let ((exp (nth 1 (assoc key double-map))))
 122              (setq double-last-event key)
 123              (setq unread-command-events
 124                    (append (substring exp 1) '(magic-start)))
 125              (vector (aref exp 0)))))))
 126
 127 ;;; Key Translation Map
 128
 129 (defvar default-key-translation-map
 130   (or key-translation-map (make-sparse-keymap))
 131   "Key translation you want to have effect, regardless of double mode.
 132 This will default to the value of `key-translation-map' when double was
 133 first loaded.")
 134
 135 (make-variable-buffer-local 'key-translation-map)
 136
 137 (defun double-setup ()
 138   ;; Setup key-translation-map as indicated by `double-map'.
 139   (setq key-translation-map (copy-keymap default-key-translation-map))
 140   (mapcar (function (lambda (entry)
 141             (define-key key-translation-map (vector (nth 0 entry))
 142                         'double-translate-key)))
 143           (append double-map '((magic-start) (magic-end)))))
 144
 145 ;;; Mode
 146
 147 (defvar double-mode nil)
 148 ;; Indicator for the double mode.
 149   (make-variable-buffer-local 'double-mode)
 150
 151 (or (assq 'double-mode minor-mode-alist)
 152     (setq minor-mode-alist
 153           (cons '(double-mode (" " double-mode-name)) minor-mode-alist)))
 154
 155 (defvar double-mode-name "Double")
 156 ;; Name of current double mode.
 157   (make-variable-buffer-local 'double-mode-name)
 158
 159 ;;;###autoload
 160 (defun double-mode (arg)
 161   "Toggle double mode.
 162 With prefix arg, turn double mode on iff arg is positive.
 163
 164 When double mode is on, some keys will insert will insert different
 165 strings when pressed twice.  See variable `double-map' for details."
 166   (interactive "P")
 167   (if (or (and (null arg) double-mode)
 168           (<= (prefix-numeric-value arg) 0))
 169       ;; Turn it off
 170       (if double-mode
 171           (progn
 172             (let ((double-map))
 173               (double-setup))
 174             (setq double-mode nil)
 175             (set-buffer-modified-p (buffer-modified-p))))
 176     ;;Turn it on
 177     (if double-mode
 178         ()
 179       (double-setup)
 180       (setq double-mode t)
 181       (set-buffer-modified-p (buffer-modified-p)))))
 182
 183 (provide 'double)
 184
 185 ;;; double.el ends here
 186