lisp/language/tml-util.el

   1 ;;; tml-util.el --- support for composing tamil characters  -*-coding: iso-2022-7bit;-*-
   2
   3 ;; Copyright (C) 2001 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: KAWABATA, Taichi <kawabata@m17n.org>
   6 ;; Keywords: multilingual, Indian, Tamil
   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 ;; Created: Nov. 08. 2002
  26
  27 ;;; Commentary:
  28
  29 ;; This file provides character(Unicode) to glyph(CDAC) conversion and
  30 ;; composition of Tamil script characters.
  31
  32 ;;; Code:
  33
  34 ;; Tamil Composable Pattern
  35 ;;    C .. Consonants
  36 ;;    V .. Vowel
  37 ;;    H .. Pulli
  38 ;;    M .. Matra
  39 ;;    V .. Vowel
  40 ;;    A .. Anuswar
  41 ;;    D .. Chandrabindu
  42 ;; 1. vowel
  43 ;;  V
  44 ;; 2. syllable : only ligature-formed pattern forms composition.
  45 ;;  (CkHCs|C)(H|M)?
  46 ;; 3. sri special
  47 ;;  (CsHCrVi)
  48
  49 ;;  oririnal
  50 ;;  ((CH)?(CH)?(CH)?CH)?C(H|M?(A|D)?)?
  51
  52 (defconst tamil-consonant
  53   "[\e$,1<5\e(B-\e$,1<Y\e(B]")
  54
  55 (defconst tamil-composable-pattern
  56   (concat
  57    "\\([\e$,1<%\e(B-\e$,1<4\e(B]\\)\\|"
  58    "[\e$,1<"<#\e(B]\\|" ;; vowel modifier considered independent
  59    "\\(\\(?:\\(?:\e$,1<5<m<W\e(B\\)\\|[\e$,1<5\e(B-\e$,1<Y\e(B]\\)[\e$,1<m<^\e(B-\e$,1<l\e(B]?\\)\\|"
  60    "\\(\e$,1<W<m<P<`\e(B\\)")
  61   "Regexp matching a composable sequence of Tamil characters.")
  62
  63 ;;;###autoload
  64 (defun tamil-compose-region (from to)
  65   (interactive "r")
  66   (save-excursion
  67     (save-restriction
  68       (narrow-to-region from to)
  69       (goto-char (point-min))
  70       (while (re-search-forward tamil-composable-pattern nil t)
  71         (tamil-compose-syllable-region (match-beginning 0)
  72                                             (match-end 0))))))
  73 (defun tamil-compose-string (string)
  74   (with-temp-buffer
  75     (insert (decompose-string string))
  76     (tamil-compose-region (point-min) (point-max))
  77     (buffer-string)))
  78
  79 (defun tamil-post-read-conversion (len)
  80   (save-excursion
  81     (save-restriction
  82       (let ((buffer-modified-p (buffer-modified-p)))
  83         (narrow-to-region (point) (+ (point) len))
  84         (tamil-compose-region (point-min) (point-max))
  85         (set-buffer-modified-p buffer-modified-p)
  86         (- (point-max) (point-min))))))
  87
  88 (defun tamil-range (from to)
  89   "Make the list of the integers of range FROM to TO."
  90   (let (result)
  91     (while (<= from to) (setq result (cons to result) to (1- to))) result))
  92
  93 (defun tamil-regexp-of-hashtbl-keys (hashtbl)
  94   "Return a regular expression that matches all keys in hashtable HASHTBL."
  95   (let ((max-specpdl-size 1000))
  96     (regexp-opt
  97      (sort
  98       (let (dummy)
  99         (maphash (function (lambda (key val) (setq dummy (cons key dummy)))) hashtbl)
 100         dummy)
 101       (function (lambda (x y) (> (length x) (length y))))))))
 102
 103
 104 ;;;###autoload
 105 (defun tamil-composition-function (from to pattern  &optional string)
 106   "Compose Tamil characters in REGION, or STRING if specified.
 107 Assume that the REGION or STRING must fully match the composable
 108 PATTERN regexp."
 109   (if string (tamil-compose-syllable-string string)
 110     (tamil-compose-syllable-region from to))
 111   (- to from))
 112
 113 ;; Register a function to compose Tamil characters.
 114 (mapc
 115  (function (lambda (ucs)
 116    (aset composition-function-table (decode-char 'ucs ucs)
 117          (list (cons tamil-composable-pattern
 118                      'tamil-composition-function)))))
 119  (nconc '(#x0b82 #x0b83) (tamil-range #x0b85 #x0bb9)))
 120
 121 ;; Notes on conversion steps.
 122
 123 ;; 1. chars to glyphs
 124 ;; Simple replacement of characters to glyphs is done.
 125
 126 ;; 2. glyphs reordering.
 127 ;; following "\e$,4)j\e(B", "\e$,4)k\e(B", "\e$,4)l\e(B" goes to the front.
 128
 129 ;; 3. glyphs to glyphs
 130 ;; reordered vowels are ligatured to consonants.
 131
 132 ;; 4. Composition.
 133 ;; left modifiers will be attached at the left.
 134 ;; others will be attached right.
 135
 136 (defvar tml-char-glyph
 137   '(;; various signs
 138     ;;("\e$,1<"\e(B" . "")
 139     ("\e$,1<#\e(B" . "\e$,4*G\e(B")
 140     ;; Independent Vowels
 141     ("\e$,1<%\e(B" . "\e$,4*<\e(B")
 142     ("\e$,1<&\e(B" . "\e$,4*=\e(B")
 143     ("\e$,1<'\e(B" . "\e$,4*>\e(B")
 144     ("\e$,1<(\e(B" . "\e$,4*?\e(B")
 145     ("\e$,1<)\e(B" . "\e$,4*@\e(B")
 146     ("\e$,1<*\e(B" . "\e$,4*A\e(B")
 147     ("\e$,1<.\e(B" . "\e$,4*B\e(B")
 148     ("\e$,1</\e(B" . "\e$,4*C\e(B")
 149     ("\e$,1<0\e(B" . "\e$,4*D\e(B")
 150     ("\e$,1<2\e(B" . "\e$,4*E\e(B")
 151     ("\e$,1<3\e(B" . "\e$,4*F\e(B")
 152     ("\e$,1<4\e(B" . "\e$,4*E*W\e(B")
 153     ;; Consonants
 154     ("\e$,1<5<m<W<m\e(B" . "\e$,4):\e(B")   ; ks.
 155     ("\e$,1<5<m<W\e(B" . "\e$,4*^\e(B")     ; ks
 156     ("\e$,1<5\e(B" . "\e$,4*H\e(B")
 157
 158     ("\e$,1<9\e(B" . "\e$,4*I\e(B")
 159     ("\e$,1<:\e(B" . "\e$,4*J\e(B")
 160     ("\e$,1<<\e(B" . "\e$,4*\\e(B")
 161     ("\e$,1<<<m\e(B" . "\e$,4)8\e(B")
 162     ("\e$,1<>\e(B" . "\e$,4*K\e(B")
 163     ("\e$,1<?\e(B" . "\e$,4*L\e(B")
 164     ("\e$,1<C\e(B" . "\e$,4*M\e(B")
 165     ("\e$,1<D\e(B" . "\e$,4*N\e(B")
 166     ("\e$,1<H\e(B" . "\e$,4*O\e(B")
 167     ("\e$,1<I\e(B" . "\e$,4*Y\e(B")
 168     ("\e$,1<I<m\e(B" . "\e$,4)a\e(B")
 169     ("\e$,1<J\e(B" . "\e$,4*P\e(B")
 170     ("\e$,1<N\e(B" . "\e$,4*Q\e(B")
 171     ("\e$,1<O\e(B" . "\e$,4*R\e(B")
 172     ("\e$,1<P\e(B" . "\e$,4*S\e(B")
 173     ("\e$,1<Q\e(B" . "\e$,4*X\e(B")
 174     ("\e$,1<R\e(B" . "\e$,4*T\e(B")
 175     ("\e$,1<S\e(B" . "\e$,4*W\e(B")
 176     ("\e$,1<T\e(B" . "\e$,4*V\e(B")
 177     ("\e$,1<U\e(B" . "\e$,4*U\e(B")
 178     ("\e$,1<W\e(B" . "\e$,4*[\e(B")
 179     ("\e$,1<W<m\e(B" . "\e$,4)7\e(B")
 180     ("\e$,1<W<m<P<`\e(B" . "\e$,4*_\e(B")
 181     ("\e$,1<X\e(B" . "\e$,4*Z\e(B")
 182     ("\e$,1<X<m\e(B" . "\e$,4)6\e(B")
 183     ("\e$,1<Y\e(B" . "\e$,4*]\e(B")
 184     ("\e$,1<Y<m\e(B" . "\e$,4)9\e(B")
 185
 186     ;; Dependent vowel signs
 187     ("\e$,1<^\e(B" . "\e$,4)c\e(B")
 188     ("\e$,1<_\e(B" . "\e$,4)d\e(B")
 189     ("\e$,1<`\e(B" . "\e$,4)f\e(B")
 190     ("\e$,1<a\e(B" . "\e$,4)g\e(B")
 191     ("\e$,1<b\e(B" . "\e$,4)h\e(B")
 192     ("\e$,1<f\e(B" . "\e$,4)j\e(B")
 193     ("\e$,1<g\e(B" . "\e$,4)k\e(B")
 194     ("\e$,1<h\e(B" . "\e$,4)l\e(B")
 195     ("\e$,1<j\e(B" . "\e$,4)j)c\e(B")
 196     ("\e$,1<k\e(B" . "\e$,4)k)c\e(B")
 197     ("\e$,1<l\e(B" . "\e$,4)j*W\e(B")
 198
 199     ;; Various signs
 200     ("\e$,1<m\e(B" . "\e$,4)b\e(B")
 201     ("\e$,1<w\e(B" . "nil") ;; not supported?
 202     ))
 203
 204 (defvar tml-char-glyph-hash
 205   (let* ((hash (make-hash-table :test 'equal)))
 206     (mapc (function (lambda (x) (puthash (car x) (cdr x) hash)))
 207           tml-char-glyph)
 208     hash))
 209
 210 (defvar tml-char-glyph-regexp
 211   (tamil-regexp-of-hashtbl-keys tml-char-glyph-hash))
 212
 213 ;; Tamil languages needed to be reordered.
 214
 215 (defvar tml-consonants-regexp
 216   "[\e$,4*H*^*I*J*\*K*L*M*N*O*Y*P*Q*R*S*X*T*W*V*U*[*Z*]\e(B]")
 217
 218 (defvar tml-glyph-reorder-key-glyphs "[\e$,4)j)k)l\e(B]")
 219
 220 (defvar tml-glyph-reordering-regexp-list
 221   (cons
 222    (concat "\\(" tml-consonants-regexp "\\)\\([\e$,4)j)k)l\e(B]\\)") "\\2\\1"))
 223
 224 ;; Tamil vowel modifiers to be ligatured.
 225 (defvar tml-glyph-glyph
 226   '(
 227     ("\e$,4*H)d\e(B" . "\e$,4(a\e(B")       ; ki
 228     ("\e$,4*^)d\e(B" . "\e$,4(v\e(B")       ; ksi
 229     ("\e$,4*^)f\e(B" . "\e$,4)2\e(B")       ; ksi~
 230     ("\e$,4*I)d\e(B" . "\e$,4(b\e(B")       ; n^i
 231     ("\e$,4*J)d\e(B" . "\e$,4(c\e(B")       ; ci
 232     ("\e$,4*K)d\e(B" . "\e$,4(d\e(B")       ; n~i
 233     ("\e$,4*L)d\e(B" . "\e$,4)n\e(B")       ; t.i
 234     ("\e$,4*M)d\e(B" . "\e$,4(e\e(B")       ; n.i
 235     ("\e$,4*N)d\e(B" . "\e$,4(f\e(B")       ; ti
 236     ("\e$,4*O)d\e(B" . "\e$,4(g\e(B")       ; ni
 237     ("\e$,4*P)d\e(B" . "\e$,4(h\e(B")       ; pi
 238     ("\e$,4*Q)d\e(B" . "\e$,4(i\e(B")       ; mi
 239     ("\e$,4*R)d\e(B" . "\e$,4(j\e(B")       ; yi
 240     ("\e$,4*S)d\e(B" . "\e$,4(k\e(B")       ; ri
 241     ("\e$,4*T)d\e(B" . "\e$,4(l\e(B")       ; li
 242     ("\e$,4*U)d\e(B" . "\e$,4(m\e(B")       ; vi
 243     ("\e$,4*V)d\e(B" . "\e$,4(n\e(B")       ; l_i
 244     ("\e$,4*W)d\e(B" . "\e$,4(o\e(B")       ; l.i
 245     ("\e$,4*X)d\e(B" . "\e$,4(p\e(B")       ; r_i
 246     ("\e$,4*Y)d\e(B" . "\e$,4(q\e(B")       ; n_i
 247     ("\e$,4*Z)d\e(B" . "\e$,4(r\e(B")       ; si
 248     ("\e$,4*[)d\e(B" . "\e$,4(s\e(B")       ; s'i
 249     ("\e$,4*\)d\e(B" . "\e$,4(t\e(B")       ; ji
 250     ("\e$,4*])d\e(B" . "\e$,4(u\e(B")       ; hi
 251
 252     ("\e$,4*H)f\e(B" . "\e$,4(w\e(B")       ; ki~
 253     ("\e$,4*I)f\e(B" . "\e$,4(x\e(B")       ; n^i~
 254     ("\e$,4*J)f\e(B" . "\e$,4(y\e(B")       ; ci~
 255     ("\e$,4*K)f\e(B" . "\e$,4(z\e(B")       ; n~i~
 256     ("\e$,4*L)f\e(B" . "\e$,4)o\e(B")       ; t.i~
 257     ("\e$,4*M)f\e(B" . "\e$,4)!\e(B")       ; n.i~
 258     ("\e$,4*N)f\e(B" . "\e$,4)"\e(B")       ; ti~
 259     ("\e$,4*O)f\e(B" . "\e$,4)#\e(B")       ; ni~
 260     ("\e$,4*P)f\e(B" . "\e$,4)$\e(B")       ; pi~
 261     ("\e$,4*Q)f\e(B" . "\e$,4)%\e(B")       ; mi~
 262     ("\e$,4*R)f\e(B" . "\e$,4)&\e(B")       ; yi~
 263     ("\e$,4*S)f\e(B" . "\e$,4)'\e(B")       ; ri~
 264     ("\e$,4*T)f\e(B" . "\e$,4)(\e(B")       ; li~
 265     ("\e$,4*U)f\e(B" . "\e$,4))\e(B")       ; vi~
 266     ("\e$,4*V)f\e(B" . "\e$,4)*\e(B")       ; l_i~
 267     ("\e$,4*W)f\e(B" . "\e$,4)+\e(B")       ; l.i~
 268     ("\e$,4*X)f\e(B" . "\e$,4),\e(B")       ; r_i~
 269     ("\e$,4*Y)f\e(B" . "\e$,4)-\e(B")       ; n_i~
 270     ("\e$,4*Z)f\e(B" . "\e$,4).\e(B")       ; si~
 271     ("\e$,4*[)f\e(B" . "\e$,4)/\e(B")       ; s'i~
 272     ("\e$,4*\)f\e(B" . "\e$,4)0\e(B")       ; ji~
 273     ("\e$,4*])f\e(B" . "\e$,4)1\e(B")       ; hi~
 274
 275     ("\e$,4*H)g\e(B" . "\e$,4)p\e(B")       ; ku
 276     ("\e$,4*I)g\e(B" . "\e$,4)q\e(B")       ; n^u
 277     ("\e$,4*J)g\e(B" . "\e$,4)r\e(B")       ; cu
 278     ("\e$,4*K)g\e(B" . "\e$,4)s\e(B")       ; n~u
 279     ("\e$,4*L)g\e(B" . "\e$,4)t\e(B")       ; t.u
 280     ("\e$,4*M)g\e(B" . "\e$,4)u\e(B")       ; n.u
 281     ("\e$,4*N)g\e(B" . "\e$,4)v\e(B")       ; tu
 282     ("\e$,4*O)g\e(B" . "\e$,4)x\e(B")       ; nu
 283     ("\e$,4*P)g\e(B" . "\e$,4)y\e(B")       ; pu
 284     ("\e$,4*Q)g\e(B" . "\e$,4)z\e(B")       ; mu
 285     ("\e$,4*R)g\e(B" . "\e$,4){\e(B")       ; yu
 286     ("\e$,4*S)g\e(B" . "\e$,4)|\e(B")       ; ru
 287     ("\e$,4*T)g\e(B" . "\e$,4)}\e(B")       ; lu
 288     ("\e$,4*U)g\e(B" . "\e$,4)~\e(B")       ; vu
 289     ("\e$,4*V)g\e(B" . "\e$,4)\x7f\e(B")       ; l_u
 290     ("\e$,4*W)g\e(B" . "\e$,4* \e(B")       ; l.u
 291     ("\e$,4*X)g\e(B" . "\e$,4*!\e(B")       ; r_u
 292     ("\e$,4*Y)g\e(B" . "\e$,4*"\e(B")       ; n_u
 293
 294     ("\e$,4*H)h\e(B" . "\e$,4*#\e(B")       ; ku~
 295     ("\e$,4*I)h\e(B" . "\e$,4*$\e(B")       ; n^u~
 296     ("\e$,4*J)h\e(B" . "\e$,4*%\e(B")       ; cu~
 297     ("\e$,4*K)h\e(B" . "\e$,4*&\e(B")       ; n~u~
 298     ("\e$,4*L)h\e(B" . "\e$,4*'\e(B")       ; t.u~
 299     ("\e$,4*M)h\e(B" . "\e$,4*(\e(B")       ; n.u~
 300     ("\e$,4*N)h\e(B" . "\e$,4*)\e(B")       ; tu~
 301     ("\e$,4*O)h\e(B" . "\e$,4*+\e(B")       ; nu~
 302     ("\e$,4*P)h\e(B" . "\e$,4*,\e(B")       ; pu~
 303     ("\e$,4*Q)h\e(B" . "\e$,4*-\e(B")       ; mu~
 304     ("\e$,4*R)h\e(B" . "\e$,4*.\e(B")       ; yu~
 305     ("\e$,4*S)h\e(B" . "\e$,4*/\e(B")       ; ru~
 306     ("\e$,4*T)h\e(B" . "\e$,4*6\e(B")       ; lu~
 307     ("\e$,4*U)h\e(B" . "\e$,4*7\e(B")       ; vu~
 308     ("\e$,4*V)h\e(B" . "\e$,4*8\e(B")       ; l_u~
 309     ("\e$,4*W)h\e(B" . "\e$,4*9\e(B")       ; l.u~
 310     ("\e$,4*X)h\e(B" . "\e$,4*:\e(B")       ; r_u~
 311     ("\e$,4*Y)h\e(B" . "\e$,4*;\e(B")       ; n_u~
 312     ))
 313
 314 (defvar tml-glyph-glyph-hash
 315   (let* ((hash (make-hash-table :test 'equal)))
 316     (mapc (function (lambda (x) (puthash (car x) (cdr x) hash)))
 317           tml-glyph-glyph)
 318     hash))
 319
 320 (defvar tml-glyph-glyph-regexp
 321   (tamil-regexp-of-hashtbl-keys tml-glyph-glyph-hash))
 322
 323 (defun tamil-compose-syllable-string (string)
 324   (with-temp-buffer
 325     (insert (decompose-string string))
 326     (tamil-compose-syllable-region (point-min) (point-max))
 327     (buffer-string)))
 328
 329 (defun tamil-compose-syllable-region (from to)
 330   "Compose tamil syllable in region FROM to TO."
 331   (let (glyph-str match-str glyph-reorder-regexps)
 332     (save-excursion
 333       (save-restriction
 334         (narrow-to-region from to)
 335         (goto-char (point-min))
 336         ;; char-glyph-conversion
 337         (while (re-search-forward tml-char-glyph-regexp nil t)
 338           (setq match-str (match-string 0))
 339           (setq glyph-str
 340                 (concat glyph-str (gethash match-str tml-char-glyph-hash))))
 341         ;; glyph reordering
 342         (when (string-match tml-glyph-reorder-key-glyphs glyph-str)
 343           (if (string-match (car tml-glyph-reordering-regexp-list)
 344                             glyph-str)
 345               (setq glyph-str
 346                     (replace-match (cdr tml-glyph-reordering-regexp-list)
 347                                    nil nil glyph-str))))
 348         ;; glyph-glyph-conversion
 349         (when (string-match tml-glyph-glyph-regexp glyph-str)
 350           (setq match-str (match-string 0 glyph-str))
 351           (setq glyph-str
 352                 (replace-match (gethash match-str tml-glyph-glyph-hash)
 353                                nil nil glyph-str)))
 354         ;; concatenate and attach reference-points.
 355         (setq glyph-str
 356               (cdr
 357                (apply
 358                 'nconc
 359                 (mapcar
 360                  (function
 361                   (lambda (x) (list '(5 . 3) x))) ;; default ref. point.
 362                  glyph-str))))
 363         (compose-region from to glyph-str)))))
 364
 365 (provide 'tml-util)
 366
 367 ;;; tml-util.el ends here