lisp/international/iso-acc.el

   1 ;;; iso-acc.el -- minor mode providing electric accent keys
   2 ;;; Copyright (C) 1993, 1994 Free Software Foundation, Inc.
   3
   4 ;; Author: Johan Vromans <jv@mh.nl>
   5 ;; Version: 1.7 (modified)
   6 ;; Maintainer: FSF
   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 2, 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
  23 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; Function `iso-accents-mode' activates a minor mode in which
  28 ;; typewriter "dead keys" are emulated.  The purpose of this emulation
  29 ;; is to provide a simple means for inserting accented characters
  30 ;; according to the ISO-8859-1 character set.
  31 ;;
  32 ;; In `iso-accents-mode', pseudo accent characters are used to
  33 ;; introduce accented keys.  The pseudo-accent characters are:
  34 ;;
  35 ;;   '  (minute)    -> grave accent
  36 ;;   `  (backtick)  -> acute accent
  37 ;;   "  (second)    -> diaeresis
  38 ;;   ^  (caret)     -> circumflex
  39 ;;   ~  (tilde)     -> tilde over the character
  40 ;;   /  (slash)     -> slash through the character.
  41 ;;                  Also:  /A is A-with-ring and /E is AE ligature.
  42 ;;
  43 ;; The action taken depends on the key that follows the pseudo accent.
  44 ;; In general:
  45 ;;
  46 ;;   pseudo-accent + appropriate letter -> accented letter
  47 ;;   pseudo-accent + space -> pseudo-accent
  48 ;;   pseudo-accent + pseudo-accent -> accent (if available)
  49 ;;   pseudo-accent + other -> pseudo-accent + other
  50 ;;
  51 ;; If the pseudo-accent is followed by anything else than a
  52 ;; self-insert-command, the dead-key code is terminated, the
  53 ;; pseudo-accent inserted 'as is' and the bell is rung to signal this.
  54 ;;
  55 ;; Function `iso-accents-mode' can be used to enable the iso accents
  56 ;; minor mode, or disable it.
  57
  58 ;; If you want only some of these characters to serve as accents,
  59 ;; set iso-accents-enable to the list of characters that should be special.
  60 \f
  61 ;;; Code:
  62
  63 (provide 'iso-acc)
  64
  65 (defvar iso-accents-list
  66   '(((?' ?A) ?\301)
  67     ((?' ?E) ?\311)
  68     ((?' ?I) ?\315)
  69     ((?' ?O) ?\323)
  70     ((?' ?U) ?\332)
  71     ((?' ?Y) ?\335)
  72     ((?' ?a) ?\341)
  73     ((?' ?e) ?\351)
  74     ((?' ?i) ?\355)
  75     ((?' ?o) ?\363)
  76     ((?' ?u) ?\372)
  77     ((?' ?y) ?\375)
  78     ((?' ?') ?\264)
  79     ((?' ? ) ?')
  80     ((?` ?A) ?\300)
  81     ((?` ?E) ?\310)
  82     ((?` ?I) ?\314)
  83     ((?` ?O) ?\322)
  84     ((?` ?U) ?\331)
  85     ((?` ?a) ?\340)
  86     ((?` ?e) ?\350)
  87     ((?` ?i) ?\354)
  88     ((?` ?o) ?\362)
  89     ((?` ?u) ?\371)
  90     ((?` ? ) ?`)
  91     ((?` ?`) ?`)                ; no special code?
  92     ((?^ ?A) ?\302)
  93     ((?^ ?E) ?\312)
  94     ((?^ ?I) ?\316)
  95     ((?^ ?O) ?\324)
  96     ((?^ ?U) ?\333)
  97     ((?^ ?a) ?\342)
  98     ((?^ ?e) ?\352)
  99     ((?^ ?i) ?\356)
 100     ((?^ ?o) ?\364)
 101     ((?^ ?u) ?\373)
 102     ((?^ ? ) ?^)
 103     ((?^ ?^) ?^)                ; no special code?
 104     ((?\" ?A) ?\304)
 105     ((?\" ?E) ?\313)
 106     ((?\" ?I) ?\317)
 107     ((?\" ?O) ?\326)
 108     ((?\" ?U) ?\334)
 109     ((?\" ?a) ?\344)
 110     ((?\" ?e) ?\353)
 111     ((?\" ?i) ?\357)
 112     ((?\" ?o) ?\366)
 113     ((?\" ?s) ?\337)
 114     ((?\" ?u) ?\374)
 115     ((?\" ?y) ?\377)
 116     ((?\" ? ) ?\")
 117     ((?\" ?\") ?\250)
 118     ((?\~ ?A) ?\303)
 119     ((?\~ ?C) ?\307)
 120     ((?\~ ?D) ?\320)
 121     ((?\~ ?N) ?\321)
 122     ((?\~ ?O) ?\325)
 123     ((?\~ ?T) ?\336)
 124     ((?\~ ?a) ?\343)
 125     ((?\~ ?c) ?\347)
 126     ((?\~ ?d) ?\360)
 127     ((?\~ ?n) ?\361)
 128     ((?\~ ?o) ?\365)
 129     ((?\~ ?t) ?\376)
 130     ((?\~ ?>) ?\273)
 131     ((?\~ ?<) ?\253)
 132     ((?\~ ?\ ) ?\~)
 133     ((?\~ ?\~) ?\270) ;; cedilla accent
 134     ((?\/ ?A) ?\305) ;; A-with-ring (Norwegian and Danish)
 135     ((?\/ ?E) ?\306) ;; AE-ligature (Norwegian and Danish)
 136     ((?\/ ?O) ?\330)
 137     ((?\/ ?a) ?\345) ;; a-with-ring (Norwegian and Danish)
 138     ((?\/ ?e) ?\346) ;; ae-ligature (Norwegian and Danish)
 139     ((?\/ ?o) ?\370)
 140     ((?\/ ?\ ) ?\/)
 141     ((?\/ ?\/) ?\260) ;; ring accent (actually degree sign?)
 142     )
 143   "Association list for ISO accent combinations.")
 144
 145 (defvar iso-accents-mode nil
 146   "*Non-nil enables ISO Accents mode.
 147 Setting this variable makes it local to the current buffer.
 148 See function `iso-accents-mode'.")
 149 (make-variable-buffer-local 'iso-accents-mode)
 150
 151 (defun iso-accents-accent-key (prompt)
 152   "Modify the following character by adding an accent to it."
 153   ;; Pick up the accent character.
 154   (if iso-accents-mode
 155       (iso-accents-compose prompt)
 156     (char-to-string last-input-char)))
 157
 158 (defun iso-accents-compose-key (prompt)
 159   "Modify the following character by adding an accent to it."
 160   ;; Pick up the accent character.
 161   (let ((combined (iso-accents-compose prompt)))
 162     (if unread-command-events
 163         (let ((unread unread-command-events))
 164           (setq unread-command-events nil)
 165           (error "Characters %s and %s cannot be composed"
 166                  (single-key-description (aref combined 0))
 167                  (single-key-description (car unread)))))
 168     combined))
 169
 170 (defun iso-accents-compose (prompt)
 171   (let* ((first-char last-input-char)
 172          ;; Wait for the second key and look up the combination.
 173          (second-char (if (or prompt
 174                               (not (eq (key-binding "a")
 175                                        'self-insert-command)))
 176                           (progn
 177                             (message "%s%c"
 178                                      (or prompt "Compose with ")
 179                                      first-char)
 180                             (read-event))
 181                         (insert first-char)
 182                         (prog1 (read-event)
 183                           (delete-region (1- (point)) (point)))))
 184          (entry (assoc (list first-char second-char) iso-accents-list)))
 185     (if entry
 186         ;; Found it: delete the first character and insert the combination.
 187         (concat (list (nth 1 entry)))
 188       ;; Otherwise, advance and schedule the second key for execution.
 189       (setq unread-command-events (list second-char))
 190       (vector first-char))))
 191
 192 (defvar iso-accents-enable '(?' ?` ?^ ?\" ?~ ?/)
 193   "*List of accent keys that become prefixes in ISO Accents mode.
 194 The default is (?' ?` ?^ ?\" ?~ ?/), which contains all the supported
 195 accent keys.  For certain languages, you might want to remove some of
 196 those characters that are not actually used.")
 197
 198 (or key-translation-map (setq key-translation-map (make-sparse-keymap)))
 199 ;; For sequences starting with an accent character,
 200 ;; use a function that tests iso-accents-mode.
 201 (if (memq ?' iso-accents-enable)
 202     (define-key key-translation-map "'"  'iso-accents-accent-key))
 203 (if (memq ?` iso-accents-enable)
 204     (define-key key-translation-map "`"  'iso-accents-accent-key))
 205 (if (memq ?^ iso-accents-enable)
 206     (define-key key-translation-map "^"  'iso-accents-accent-key))
 207 (if (memq ?\" iso-accents-enable)
 208     (define-key key-translation-map "\"" 'iso-accents-accent-key))
 209 (if (memq ?~ iso-accents-enable)
 210     (define-key key-translation-map "~" 'iso-accents-accent-key))
 211 (if (memq ?/ iso-accents-enable)
 212     (define-key key-translation-map "/" 'iso-accents-accent-key))
 213
 214 ;; It is a matter of taste if you want the minor mode indicated
 215 ;; in the mode line...
 216 ;; If so, uncomment the next four lines.
 217 ;; (or (assq 'iso-accents-mode minor-mode-map-alist)
 218 ;;     (setq minor-mode-alist
 219 ;;        (append minor-mode-alist
 220 ;;                '((iso-accents-mode " ISO-Acc")))))
 221
 222 ;;;###autoload
 223 (defun iso-accents-mode (&optional arg)
 224   "Toggle ISO Accents mode, in which accents modify the following letter.
 225 This permits easy insertion of accented characters according to ISO-8859-1.
 226 When Iso-accents mode is enabled, accent character keys
 227 \(`, ', \", ^, / and ~) do not self-insert; instead, they modify the following
 228 letter key so that it inserts an ISO accented letter.
 229
 230 The variable `iso-accents-enable' specifies the list of characters to
 231 enable as accents.  If you don't need all of them, remove the ones you
 232 don't need from that list.
 233
 234 Special combinations: ~c gives a c with cedilla,
 235 ~d gives an Icelandic eth (d with dash).
 236 ~t gives an Icelandic thorn.
 237 \"s gives German sharp s.
 238 /a gives a with ring.
 239 /e gives an a-e ligature.
 240 ~< and ~> give guillemets.
 241
 242 With an argument, a positive argument enables ISO Accents mode,
 243 and a negative argument disables it."
 244
 245   (interactive "P")
 246
 247   (if (if arg
 248           ;; Negative arg means switch it off.
 249           (<= (prefix-numeric-value arg) 0)
 250         ;; No arg means toggle.
 251         iso-accents-mode)
 252       (setq iso-accents-mode nil)
 253
 254     ;; Enable electric accents.
 255     (setq iso-accents-mode t)))
 256
 257 ;;; iso-acc.el ends here