lisp/language/tibet-util.el

   1 ;;; tibet-util.el --- utilities for Tibetan   -*- coding: iso-2022-7bit; -*-
   2
   3 ;; Copyright (C) 1995 Electrotechnical Laboratory, JAPAN.
   4 ;; Licensed to the Free Software Foundation.
   5
   6 ;; Keywords: multilingual, Tibetan
   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 the
  22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;; Author: Toru TOMABECHI, <Toru.Tomabechi@orient.unil.ch>
  26
  27 ;; Created: Feb. 17. 1997
  28
  29 ;;; History:
  30 ;; 1997.03.13 Modification in treatment of text properties;
  31 ;;            Support for some special signs and punctuations.
  32 ;; 1999.10.25 Modification for a new composition way by K.Handa.
  33
  34 ;;; Commentary:
  35
  36 ;;; Code:
  37
  38 (defconst tibetan-obsolete-glyphs
  39   `(("\e$(7!=\e(B" . "\e$(8!=\e(B")                 ; 2 col <-> 1 col
  40     ("\e$(7!?\e(B" . "\e$(8!?\e(B")
  41     ("\e$(7!@\e(B" . "\e$(8!@\e(B")
  42     ("\e$(7!A\e(B" . "\e$(8!A\e(B")
  43     ("\e$(7"`\e(B" . "\e$(8"`\e(B")
  44     ("\e$(7!;\e(B" . "\e$(8!;\e(B")
  45     ("\e$(7!D\e(B" . "\e$(8!D\e(B")
  46     ;; Yes these are dirty. But ...
  47     ("\e$(7!>\e(B \e$(7!>\e(B" . ,(compose-string "\e$(7!>\e(B \e$(7!>\e(B" 0 3 [?\e$(7!>\e(B (Br . Bl) ?  (Br . Bl) ?\e$(7!>\e(B]))
  48     ("\e$(7!4!5!5\e(B" . ,(compose-string
  49                   "\e$(7#R#S#S#S\e(B" 0 4
  50                   [?\e$(7#R\e(B (Br . Bl) ?\e$(7#S\e(B (Br . Bl) ?\e$(7#S\e(B (Br . Bl) ?\e$(7#S\e(B]))
  51     ("\e$(7!4!5\e(B" . ,(compose-string "\e$(7#R#S#S\e(B" 0 3 [?\e$(7#R\e(B (Br . Bl) ?\e$(7#S\e(B (Br . Bl) ?\e$(7#S\e(B]))
  52     ("\e$(7!6\e(B" . ,(compose-string "\e$(7#R#S!I\e(B" 0 3 [?\e$(7#R\e(B (Br . Bl) ?\e$(7#S\e(B (br . tr) ?\e$(7!I\e(B]))
  53     ("\e$(7!4\e(B"   . ,(compose-string "\e$(7#R#S\e(B" 0 2 [?\e$(7#R\e(B (Br . Bl) ?\e$(7#S\e(B]))))
  54
  55 ;;;###autoload
  56 (defun tibetan-char-p (ch)
  57   "Check if char CH is Tibetan character.
  58 Returns non-nil if CH is Tibetan. Otherwise, returns nil."
  59   (memq (char-charset ch) '(tibetan tibetan-1-column)))
  60
  61 ;;; Functions for Tibetan <-> Tibetan-transcription.
  62
  63 ;;;###autoload
  64 (defun tibetan-tibetan-to-transcription (str)
  65   "Transcribe Tibetan string STR and return the corresponding Roman string."
  66   (let (;; Accumulate transcriptions here in reverse order.
  67         (trans nil)
  68         (len (length str))
  69         (i 0)
  70         ch this-trans)
  71     (while (< i len)
  72       (let ((idx (string-match tibetan-precomposition-rule-regexp str i)))
  73         (if (eq idx i)
  74             ;; Ith character and the followings matches precomposable
  75             ;; Tibetan sequence.
  76             (setq i (match-end 0)
  77                   this-trans
  78                   (car (rassoc
  79                         (cdr (assoc (match-string 0 str)
  80                                     tibetan-precomposition-rule-alist))
  81                         tibetan-precomposed-transcription-alist)))
  82           (setq ch (substring str i (1+ i))
  83                 i (1+ i)
  84                 this-trans
  85                 (car (or (rassoc ch tibetan-consonant-transcription-alist)
  86                          (rassoc ch tibetan-vowel-transcription-alist)
  87                          (rassoc ch tibetan-subjoined-transcription-alist)))))
  88         (setq trans (cons this-trans trans))))
  89     (apply 'concat (nreverse trans))))
  90
  91 ;;;###autoload
  92 (defun tibetan-transcription-to-tibetan (str)
  93   "Convert Tibetan Roman string STR to Tibetan character string.
  94 The returned string has no composition information."
  95   (let (;; Case is significant.
  96         (case-fold-search nil)
  97         (idx 0)
  98         ;; Accumulate Tibetan strings here in reverse order.
  99         (t-str-list nil)
 100         i subtrans)
 101     (while (setq i (string-match tibetan-regexp str idx))
 102       (if (< idx i)
 103           ;; STR contains a pattern that doesn't match Tibetan
 104           ;; transcription.  Include the pattern as is.
 105           (setq t-str-list (cons (substring str idx i) t-str-list)))
 106       (setq subtrans (match-string 0 str)
 107             idx (match-end 0))
 108       (let ((t-char (cdr (assoc subtrans
 109                                 tibetan-precomposed-transcription-alist))))
 110         (if t-char
 111             ;; SUBTRANS corresponds to a transcription for
 112             ;; precomposable Tibetan sequence.
 113             (setq t-char (car (rassoc t-char
 114                                       tibetan-precomposition-rule-alist)))
 115           (setq t-char
 116                 (cdr
 117                  (or (assoc subtrans tibetan-consonant-transcription-alist)
 118                      (assoc subtrans tibetan-vowel-transcription-alist)
 119                      (assoc subtrans tibetan-modifier-transcription-alist)
 120                      (assoc subtrans tibetan-subjoined-transcription-alist)))))
 121         (setq t-str-list (cons t-char t-str-list))))
 122     (if (< idx (length str))
 123         (setq t-str-list (cons (substring str idx) t-str-list)))
 124     (apply 'concat (nreverse t-str-list))))
 125
 126 ;;;
 127 ;;; Functions for composing/decomposing Tibetan sequence.
 128 ;;;
 129 ;;; A Tibetan syllable is typically structured as follows:
 130 ;;;
 131 ;;;      [Prefix] C [C+] V [M] [Suffix [Post suffix]]
 132 ;;;
 133 ;;; where C's are all vertically stacked, V appears below or above
 134 ;;; consonant cluster and M is always put above the C[C+]V combination.
 135 ;;; (Sanskrit visarga, though it is a vowel modifier, is considered
 136 ;;;  to be a punctuation.)
 137 ;;;
 138 ;;; Here are examples of the words "bsgrubs" and "hfauM"
 139 ;;;
 140 ;;;            \e4\e$(7"7\e0"7\e1\e4%qx!"U\e0"G###C"U\e1\e4"7\e0"7\e1\e4"G\e0"G\e1\e(B            \e4\e$(7"Hx!"Rx!"Ur'"_\e0"H"R"U"_\e1\e(B
 141 ;;;
 142 ;;;                             M
 143 ;;;             b s b s         h
 144 ;;;               g             fa
 145 ;;;               r             u
 146 ;;;               u
 147 ;;;
 148 ;;; Consonants `'' (\e$(7"A\e(B), `w' (\e$(7">\e(B), `y' (\e$(7"B\e(B), `r' (\e$(7"C\e(B) take special
 149 ;;; forms when they are used as subjoined consonant.  Consonant `r'
 150 ;;; takes another special form when used as superjoined in such a case
 151 ;;; as "rka", while it does not change its form when conjoined with
 152 ;;; subjoined `'', `w' or `y' as in "rwa", "rya".
 153
 154 ;; Append a proper composition rule and glyph to COMPONENTS to compose
 155 ;; CHAR with a composition that has COMPONENTS.
 156
 157 (defun tibetan-add-components (components char)
 158   (let ((last (last components))
 159         (stack-upper '(tc . bc))
 160         (stack-under '(bc . tc))
 161         rule comp-vowel tmp)
 162     ;; Special treatment for 'a chung.
 163     ;; If 'a follows a consonant, turn it into the subjoined form.
 164     ;; * Disabled by Tomabechi 2000/06/09 *
 165     ;; Because in Unicode, \e$(7"A\e(B may follow directly a consonant without
 166     ;; any intervening vowel, as in \e4\e$(7"9\e0"9\e1\e4""\e0"""Q\e1\e4"A\e0"A\e1!;\e(B=\e4\e$(7"9\e0"9\e1\e(B \e4\e$(7""\e0""\e1\e(B \e4\e$(7"A\e0"A\e1\e(B not \e4\e$(7"9\e0"9\e1\e(B \e4\e$(7""\e0""\e1\e(B \e$(7"Q\e(B \e4\e$(7"A\e0"A\e1\e(B
 167     ;;(if (and (= char ?\e$(7"A\e(B)
 168     ;;       (aref (char-category-set (car last)) ?0))
 169     ;;  (setq char ?\e$(7"R\e(B)) ;; modified for new font by Tomabechi 1999/12/10
 170
 171     ;; Composite vowel signs are decomposed before being added
 172     ;; Added by Tomabechi 2000/06/08
 173     (if (memq char '(?\e$(7"T\e(B ?\e$(7"V\e(B ?\e$(7"W\e(B ?\e$(7"X\e(B ?\e$(7"Y\e(B ?\e$(7"Z\e(B ?\e$(7"b\e(B))
 174         (setq comp-vowel
 175               (copy-sequence
 176                (cddr (assoc (char-to-string char)
 177                             tibetan-composite-vowel-alist)))
 178               char
 179               (cadr (assoc (char-to-string char)
 180                            tibetan-composite-vowel-alist))))
 181     (cond
 182      ;; Compose upper vowel sign vertically over.
 183      ((aref (char-category-set char) ?2)
 184       (setq rule stack-upper))
 185
 186      ;; Compose lower vowel sign vertically under.
 187      ((aref (char-category-set char) ?3)
 188       (if (eq char ?\e$(7"Q\e(B)          ;; `\e$(7"Q\e(B' should not visible when composed.
 189           (setq rule nil)
 190         (setq rule stack-under)))
 191      ;; Transform ra-mgo (superscribed r) if followed by a subjoined
 192      ;; consonant other than w, ', y, r.
 193      ((and (= (car last) ?\e$(7"C\e(B)
 194            (not (memq char '(?\e$(7#>\e(B ?\e$(7"R\e(B ?\e$(7#B\e(B ?\e$(7#C\e(B))))
 195       (setcar last ?\e$(7!"\e(B) ;; modified for newfont by Tomabechi 1999/12/10
 196       (setq rule stack-under))
 197      ;; Transform initial base consonant if followed by a subjoined
 198      ;; consonant but 'a.
 199      (t
 200       (let ((laststr (char-to-string (car last))))
 201         (if (and (/= char ?\e$(7"R\e(B) ;; modified for new font by Tomabechi
 202                  (string-match "[\e$(7"!\e(B-\e$(7"="?"@"D\e(B-\e$(7"J"K\e(B]" laststr))
 203             (setcar last (string-to-char
 204                           (cdr (assoc (char-to-string (car last))
 205                                       tibetan-base-to-subjoined-alist)))))
 206         (setq rule stack-under))))
 207
 208     (if rule
 209         (setcdr last (list rule char)))
 210     ;; Added by Tomabechi 2000/06/08
 211     (if comp-vowel
 212         (nconc last comp-vowel))
 213     ))
 214
 215 ;;;###autoload
 216 (defun tibetan-compose-string (str)
 217   "Compose Tibetan string STR."
 218   (let ((idx 0))
 219     ;; `\e$(7"A\e(B' is included in the pattern for subjoined consonants
 220     ;; because we treat it specially in tibetan-add-components.
 221     ;; (This feature is removed by Tomabechi 2000/06/08)
 222     (while (setq idx (string-match tibetan-composable-pattern str idx))
 223       (let ((from idx)
 224             (to (match-end 0))
 225             components)
 226         (if (eq (string-match tibetan-precomposition-rule-regexp str idx) idx)
 227             (setq idx (match-end 0)
 228                   components
 229                   (list (string-to-char
 230                          (cdr
 231                           (assoc (match-string 0 str)
 232                                  tibetan-precomposition-rule-alist)))))
 233           (setq components (list (aref str idx))
 234                 idx (1+ idx)))
 235         (while (< idx to)
 236           (tibetan-add-components components (aref str idx))
 237           (setq idx (1+ idx)))
 238         (compose-string str from to components))))
 239   str)
 240
 241 ;;;###autoload
 242 (defun tibetan-compose-region (beg end)
 243   "Compose Tibetan text the region BEG and END."
 244   (interactive "r")
 245   (let (str result chars)
 246     (save-excursion
 247       (save-restriction
 248         (narrow-to-region beg end)
 249         (goto-char (point-min))
 250         ;; `\e$(7"A\e(B' is included in the pattern for subjoined consonants
 251         ;; because we treat it specially in tibetan-add-components.
 252         ;; (This feature is removed by Tomabechi 2000/06/08)
 253         (while (re-search-forward tibetan-composable-pattern nil t)
 254           (let ((from (match-beginning 0))
 255                 (to (match-end 0))
 256                 components)
 257             (goto-char from)
 258             (if (looking-at tibetan-precomposition-rule-regexp)
 259                 (progn
 260                   (setq components
 261                         (list (string-to-char
 262                                (cdr
 263                                 (assoc (match-string 0)
 264                                        tibetan-precomposition-rule-alist)))))
 265                   (goto-char (match-end 0)))
 266               (setq components (list (char-after from)))
 267               (forward-char 1))
 268             (while (< (point) to)
 269               (tibetan-add-components components (following-char))
 270               (forward-char 1))
 271             (compose-region from to components)))))))
 272
 273 (defvar tibetan-decompose-precomposition-alist
 274   (mapcar (function (lambda (x) (cons (string-to-char (cdr x)) (car x))))
 275           tibetan-precomposition-rule-alist))
 276
 277 ;;;###autoload
 278 (defun tibetan-decompose-region (from to)
 279   "Decompose Tibetan text in the region FROM and TO.
 280 This is different from decompose-region because precomposed Tibetan characters
 281 are decomposed into normal Tibetan character sequences."
 282   (interactive "r")
 283   (save-restriction
 284     (narrow-to-region from to)
 285     (decompose-region from to)
 286     (goto-char from)
 287     (while (not (eobp))
 288       (let* ((char (following-char))
 289              (slot (assq char tibetan-decompose-precomposition-alist)))
 290         (if slot
 291             (progn
 292               (delete-char 1)
 293               (insert (cdr slot)))
 294           (forward-char 1))))))
 295
 296
 297 ;;;###autoload
 298 (defun tibetan-decompose-string (str)
 299   "Decompose Tibetan string STR.
 300 This is different from decompose-string because precomposed Tibetan characters
 301 are decomposed into normal Tibetan character sequences."
 302   (let ((new "")
 303         (len (length str))
 304         (idx 0)
 305         char slot)
 306     (while (< idx len)
 307       (setq char (aref str idx)
 308             slot (assq (aref str idx) tibetan-decompose-precomposition-alist)
 309             new (concat new (if slot (cdr slot) (char-to-string char)))
 310             idx (1+ idx)))
 311     new))
 312
 313 ;;;###autoload
 314 (defun tibetan-composition-function (from to pattern &optional string)
 315   (if string
 316       (tibetan-compose-string string)
 317     (tibetan-compose-region from to))
 318   (- to from))
 319
 320 ;;;
 321 ;;; This variable is used to avoid repeated decomposition.
 322 ;;;
 323 (setq-default tibetan-decomposed nil)
 324
 325 ;;;###autoload
 326 (defun tibetan-decompose-buffer ()
 327   "Decomposes Tibetan characters in the buffer into their components.
 328 See also the documentation of the function `tibetan-decompose-region'."
 329   (interactive)
 330   (make-local-variable 'tibetan-decomposed)
 331   (cond ((not tibetan-decomposed)
 332          (tibetan-decompose-region (point-min) (point-max))
 333          (setq tibetan-decomposed t))))
 334
 335 ;;;###autoload
 336 (defun tibetan-compose-buffer ()
 337   "Composes Tibetan character components in the buffer.
 338 See also docstring of the function tibetan-compose-region."
 339   (interactive)
 340   (make-local-variable 'tibetan-decomposed)
 341   (tibetan-compose-region (point-min) (point-max))
 342   (setq tibetan-decomposed nil))
 343
 344 ;;;###autoload
 345 (defun tibetan-post-read-conversion (len)
 346   (save-excursion
 347     (save-restriction
 348       (let ((buffer-modified-p (buffer-modified-p)))
 349         (narrow-to-region (point) (+ (point) len))
 350         (tibetan-compose-region (point-min) (point-max))
 351         (set-buffer-modified-p buffer-modified-p)
 352         (make-local-variable 'tibetan-decomposed)
 353         (setq tibetan-decomposed nil)
 354         (- (point-max) (point-min))))))
 355
 356
 357 ;;;###autoload
 358 (defun tibetan-pre-write-conversion (from to)
 359   (setq tibetan-decomposed-temp tibetan-decomposed)
 360   (let ((old-buf (current-buffer)))
 361     (set-buffer (generate-new-buffer " *temp*"))
 362     (if (stringp from)
 363         (insert from)
 364       (insert-buffer-substring old-buf from to))
 365     (if (not tibetan-decomposed-temp)
 366         (tibetan-decompose-region (point-min) (point-max)))
 367     ;; Should return nil as annotations.
 368     nil))
 369
 370 \f
 371 ;;;
 372 ;;; Unicode-related definitions.
 373 ;;;
 374
 375 (defvar tibetan-canonicalize-for-unicode-alist
 376   '(("\e$(7"Q\e(B" . "")  ;; remove vowel a
 377     ("\e$(7"T\e(B" . "\e$(7"R"S\e(B") ;; decompose vowels whose use is ``discouraged'' in Unicode 3.0
 378     ("\e$(7"V\e(B" . "\e$(7"R"U\e(B")
 379     ("\e$(7"W\e(B" . "\e$(7#C"a\e(B")
 380     ("\e$(7"X\e(B" . "\e$(7#C"R"a\e(B")
 381     ("\e$(7"Y\e(B" . "\e$(7#D"a\e(B")
 382     ("\e$(7"Z\e(B" . "\e$(7#D"R"a\e(B")
 383     ("\e$(7"b\e(B" . "\e$(7"R"a\e(B"))
 384   "Rules for canonicalizing Tibetan vowels for Unicode.")
 385
 386 (defvar tibetan-canonicalize-for-unicode-regexp
 387   "[\e$(7"Q"T"V"W"X"Y"Z"b\e(B]"
 388   "Regexp for Tibetan vowels to be canonicalized in Unicode.")
 389
 390 (defun tibetan-canonicalize-for-unicode-region (from to)
 391   (save-restriction
 392     (narrow-to-region from to)
 393     (goto-char from)
 394     (while (re-search-forward tibetan-canonicalize-for-unicode-regexp nil t)
 395       (let (
 396             ;;(from (match-beginning 0))
 397             ;;(to (match-end 0))
 398             (canonical-form
 399              (cdr (assoc (match-string 0)
 400                          tibetan-canonicalize-for-unicode-alist))))
 401         ;;(goto-char from)
 402         ;;(delete-region from to)
 403         ;;(insert canonical-form)
 404         (replace-match canonical-form)
 405         ))))
 406
 407 (defvar tibetan-strict-unicode t
 408   "*Flag to control Tibetan canonicalizing for Unicode.
 409
 410 If non-nil, the vowel a is removed and composite vowels are decomposed
 411 before writing buffer in Unicode.  See also
 412 `tibetan-canonicalize-for-unicode-regexp' and
 413 `tibetan-canonicalize-for-unicode-alist'.")
 414
 415 ;;;###autoload
 416 (defun tibetan-pre-write-canonicalize-for-unicode (from to)
 417   (let ((old-buf (current-buffer))
 418         (strict-unicode tibetan-strict-unicode))
 419     (set-buffer (generate-new-buffer " *temp*"))
 420     (if (stringp from)
 421         (insert from)
 422       (insert-buffer-substring old-buf from to))
 423     (if strict-unicode
 424         (tibetan-canonicalize-for-unicode-region (point-min) (point-max)))
 425     ;; Should return nil as annotations.
 426     nil))
 427
 428 (provide 'tibet-util)
 429
 430 ;;; tibet-util.el ends here