lisp/double.el

   1 ;;; double.el --- support for keyboard remapping with double clicking
   2
   3 ;; Copyright (C) 1994, 1997, 1998, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007 Free Software Foundation, Inc.
   5
   6 ;; Author: Per Abrahamsen <abraham@dina.kvl.dk>
   7 ;; Keywords: i18n
   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, or (at your option)
  14 ;; 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; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This mode is intended for use with languages that adds a small
  29 ;; number of extra letters not available on the keyboard.
  30 ;;
  31 ;; Examples includes Scandinavian and German with an US keyboard.
  32 ;;
  33 ;; The idea is that certain keys are overloaded.  When you press it
  34 ;; once it will insert one string, and when you press it twice the
  35 ;; string will be replaced by another.  This can be used for mapping
  36 ;; keys on a US keyboard to generate characters according to the local
  37 ;; keyboard convention when pressed once, and according to US keyboard
  38 ;; convention when pressed twice.
  39 ;;
  40 ;; To use this mode, you must define the variable `double-map' and
  41 ;; then enable double mode with `M-x double-mode'.  Read the
  42 ;; documentation for both of them.
  43 ;;
  44 ;; The default mapping is for getting Danish/Norwegian keyboard layout
  45 ;; using ISO Latin 1 on a US keyboard.
  46 ;;
  47 ;; Important node: While I would like to hear comments, bug reports,
  48 ;; suggestions, please do @strong{not} expect me to put other mappings
  49 ;; than 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 ;;; Code:
  54
  55 (defgroup double nil
  56   "Remap keyboard, but get original by typing the same key twice."
  57   :group 'i18n)
  58
  59 (defcustom double-map
  60   '((?\; "\346" ";")
  61     (?\' "\370" "'")
  62     (?\[ "\345" "[")
  63     (?\: "\306" ":")
  64     (?\" "\330" "\"")
  65     (?\{ "\305" "{"))
  66   "Alist of key translations activated by double mode.
  67
  68 Each entry is a list with three elements:
  69 1. The key activating the translation.
  70 2. The string to be inserted when the key is pressed once.
  71 3. The string to be inserted when the key is pressed twice."
  72   :group 'double
  73   :type '(repeat (list (character :tag "Key")
  74                        (string :tag "Once")
  75                        (string :tag "Twice"))))
  76
  77 (defcustom double-prefix-only t
  78   "Non-nil means that Double mode mapping only works for prefix keys.
  79 That is, for any key `X' in `double-map', `X' alone will be mapped
  80 but not `C-u X' or `ESC X' since the X is not the prefix key."
  81   :group 'double
  82   :type 'boolean)
  83
  84 ;;; Read Event
  85
  86 (defvar double-last-event nil)
  87 ;; The last key that generated a double key event.
  88
  89 (defun double-read-event (prompt)
  90   ;; Read an event
  91   (if isearch-mode (isearch-update))
  92   (if prompt
  93       (prog2 (message "%s%c" prompt double-last-event)
  94           (read-event)
  95         (message ""))
  96     (read-event)))
  97
  98 (global-set-key [ignore] 'ignore)
  99
 100 (or (boundp 'isearch-mode-map)
 101     (load-library "isearch"))
 102
 103 (define-key isearch-mode-map [ignore]
 104   (function (lambda () (interactive) (isearch-update))))
 105
 106 (defun double-translate-key (prompt)
 107   ;; Translate input events using double map.
 108   (let ((key last-input-char))
 109     (cond (unread-command-events
 110            ;; Artificial event, ignore it.
 111            (vector key))
 112           ((and double-prefix-only
 113                 (> (length (this-command-keys)) 1))
 114            ;; This is not a prefix key, ignore it.
 115            (vector key))
 116           ((eq key 'magic-start)
 117            ;; End of generated event.  See if he will repeat it...
 118            (let ((new (double-read-event prompt))
 119                  (entry (assoc double-last-event double-map)))
 120              (force-window-update (selected-window))
 121              (if (eq new double-last-event)
 122                  (progn
 123                    (setq unread-command-events
 124                          (append (make-list (1- (length (nth 1 entry)))
 125                                             127)
 126                                  (nth 2 entry)
 127                                  '(magic-end)))
 128                    (vector 127))
 129                (setq unread-command-events (list new))
 130                [ignore])))
 131           ((eq key 'magic-end)
 132            ;; End of double event.  Ignore.
 133            [ignore])
 134           (t
 135            ;; New key.
 136            (let ((exp (nth 1 (assoc key double-map))))
 137              (setq double-last-event key)
 138              (setq unread-command-events
 139                    (append (substring exp 1) '(magic-start)))
 140              (vector (aref exp 0)))))))
 141
 142 ;;; Mode
 143
 144 ;; This feature seemed useless and it confused describe-mode,
 145 ;; so I deleted it.
 146 ;; (defvar double-mode-name "Double")
 147 ;; ;; Name of current double mode.
 148 ;; (make-variable-buffer-local 'double-mode-name)
 149
 150 ;;;###autoload
 151 (define-minor-mode double-mode
 152   "Toggle Double mode.
 153 With prefix argument ARG, turn Double mode on if ARG is positive, otherwise
 154 turn it off.
 155
 156 When Double mode is on, some keys will insert different strings
 157 when pressed twice.  See variable `double-map' for details."
 158   :lighter " Double"
 159   :link '(emacs-commentary-link "double")
 160   (kill-local-variable 'key-translation-map)
 161   (when double-mode
 162     ;; Set up key-translation-map as indicated by `double-map'.
 163     ;; XXX I don't think key-translation-map should be made local here. -- Lorentey
 164     (make-local-variable 'key-translation-map)
 165     (let ((map (make-sparse-keymap)))
 166       (set-keymap-parent map key-translation-map)
 167       (setq key-translation-map map)
 168       (dolist (entry (append double-map '((magic-start) (magic-end))))
 169         (define-key map
 170           (vector (nth 0 entry)) 'double-translate-key)))))
 171
 172 (provide 'double)
 173
 174 ;; arch-tag: 2e170036-44cb-4493-bc32-ada0a4395221
 175 ;;; double.el ends here