emacs/lisp/language/devan-util.el

;;; devan-util.el --- Support for composing Devanagari characters

;; Copyright (C) 2001 Free Software Foundation, Inc.

;; Maintainer:  KAWABATA, Taichi <batta@beige.ocn.ne.jp>
;; Keywords: multilingual, Devanagari

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;; Created: Feb. 17. 2001

;;; Commentary:

;; This file provides character(Unicode) to glyph(CDAC) conversion and
;; composition of Devanagari script characters.

;;; Code:


;; Devanagari Composable Pattern
;;    C .. Consonants
;;    V .. Vowel
;;    H .. Halant
;;    M .. Matra
;;    V .. Vowel
;;    A .. Anuswar
;;    D .. Chandrabindu
;;    (N .. Zerowidth Non Joiner)
;;    (J .. Zerowidth Joiner.  )
;; 1. vowel
;;  V(A/D)?
;; 2. syllable : maximum of 5 consecutive consonants.  (e.g. kartsnya)
;;  ((CH)?(CH)?(CH)?CH)?C(MA?|D|H)?

(defconst devanagari-consonant
  "[$,15U(B-$,15y68(B-$,16?(B]")

(defconst devanagari-composable-pattern
  (concat 
   "\\([$,15E(B-$,15T6@6A(B][$,15A5B(B]?\\)\\|$,15C(B"
   "\\|\\("
   "\\(?:\\(?:[$,15U(B-$,15y68(B-$,16?(B]$,16-(B\\)?\\(?:[$,15U(B-$,15y68(B-$,16?(B]$,16-(B\\)?\\(?:[$,15U(B-$,15y68(B-$,16?(B]$,16-(B\\)?[$,15U(B-$,15y68(B-$,16?(B]$,16-(B\\)?"
   "[$,15U(B-$,15y68(B-$,16?(B]\\(?:$,16-(B\\|[$,15~(B-$,16-6B6C(B]?[$,15B5A(B]?\\)?"
   "\\)")
  "Regexp matching a composable sequence of Devanagari characters.")

(defun devanagari-compose-region (from to)
  (interactive "r")
  (save-excursion
    (save-restriction
      (narrow-to-region from to)
      (goto-char (point-min))
      (while (re-search-forward devanagari-composable-pattern nil t)
        (devanagari-compose-syllable-region (match-beginning 0) 
                                            (match-end 0))))))
(defun devanagari-compose-string (string)
  (with-temp-buffer
    (insert (decompose-string string))
    (devanagari-compose-region (point-min) (point-max))
    (buffer-string)))

(defun range (from to)
  "Make the list of the integers of range FROM to TO."
  (let (result) 
    (while (<= from to) (setq result (cons to result) to (1- to))) result))

(defun regexp-of-hashtbl-keys (hashtbl)
  "Returns the regular expression of hashtable keys."
  (let ((max-specpdl-size 1000))
    (regexp-opt
     (sort 
      (let (dummy)
	(maphash (function (lambda (key val) (setq dummy (cons key dummy)))) hashtbl)
	dummy)
      (function (lambda (x y) (> (length x) (length y))))))))

(defun devanagari-composition-function (from to pattern &optional string)
  "Compose Devanagari characters in REGION, or STRING if specified.
Assume that the REGION or STRING must fully match the composable
PATTERN regexp."
  (if string (devanagari-compose-syllable-string string)
    (devanagari-compose-syllable-region from to))
  (- to from))

;; Register a function to compose Devanagari characters.
(mapc
 (function (lambda (ucs)
   (aset composition-function-table (decode-char 'ucs ucs)
	 (list (cons devanagari-composable-pattern 
                     'devanagari-composition-function)))))
 (nconc '(#x0903) (range #x0905 #x0939) (range #x0958 #x0961)))

;; Notes on conversion steps.

;; 1. chars to glyphs 
;;
;; Rules will not be applied to the halant appeared at the end of the
;; text.  Also, the preceding/following "r" will be treated as special case.

;; 2. glyphs reordering.
;;
;; The glyphs are split by halant, and each glyph groups are
;; re-ordered in the following order.
;;
;; Note that `consonant-glyph' mentioned here does not contain the
;; vertical bar (right modifier) attached at the right of the
;; consonant.
;; 
;; If the glyph-group contains right modifier, 
;;  (1) consonant-glyphs/vowels, with nukta sign
;;  (2) spacing
;;  (3) right modifier (may be matra)
;;  (4) top matra
;;  (5) preceding "r"
;;  (6) anuswar
;;  (7) following "r"
;;  (8) bottom matra or halant.
;; 
;; Otherwise, 
;;  (1) consonant-glyph/vowels, with nukta sign
;;  (3) left matra
;;  (4) top matra 
;;  (5) preceding "r"
;;  (6) anuswar
;;  (7) following "r"
;;  (8) bottom matra or halant.
;;  (2) spacing

;; 3. glyph to glyph
;;
;; For better display, some glyph display would be tuned.

;; 4. Composition.
;;
;; left modifiers will be attached at the left.
;; others will be attached right.

;; Problem::
;;  Can we generalize this methods to other Indian scripts?

(defvar dev-char-glyph
  '(("$,15E(B" . "$,4 K(B")
    ("$,15F(B" . "$,4 K\"(B)")
    ("$,15~(B" . "$,4\"(B)")
    ("$,15G(B" . "$,4 \(B")
    ("$,15(B" . "$,4\"(B*")
    ("$,155A(B" . "$,4\"(B*\$,4\"(B&")
    ("$,15H(B" . "$,4 \"'(B")
    ("$,15H5A(B" . "$,4 \"'\"(B&")
    ("$,16 (B" . "$,4\"(B2")
    ("$,16 5A(B" . "$,4\"2\"&(B")
    ("$,15I(B" . "$,4 ](B")
    ("$,16!(B" . "$,4\"(B6")
    ("$,15J(B" . "$,4 ^\"(BP")
    ("$,16"(B" . "$,4\"(B:")
    ("$,15K(B" . "$,4 `\"(BQ")
    ("$,16#(B" . "$,4\"(B>")
    ;;("$,15L(B" . nil) ; not implemented.
    ("$,16$(B" . "$,4\"(B?")
    ("$,15M(B" . "$,4 b\"(BL")
    ("$,15M5A(B" . "$,4 b\"(B$")
    ("$,15M5B(B" . "$,4 b\"(B$")
    ("$,16%(B" . "\$,4\"(BL")
    ("$,15N(B" . "$,4 b\"(B@") 
    ("$,15N5A(B" . "$,4 b\"@\"&(B") 
    ("$,16&(B" . "\$,4\"(B@")
    ("$,16&5A(B" . "\$,4\"(B@\$,4\"(B&")
    ("$,15O(B" . "$,4 b(B") 
    ("$,16'(B" . "\$,4\"(BD")
    ("$,16'5A(B" . "\$,4\"(BD\$,4\"(B&")
    ("$,15P(B" . "$,4 b\"(BD") 
    ("$,15P5A(B" . "$,4 b\"D\"&(B") 
    ("$,16((B" . "\$,4\"(BH")
    ("$,16(5A(B" . "\$,4\"(BH\$,4\"(B&")
    ("$,15Q(B" . "$,4 K\")\"L(B") ;; special rule for reodering.
    ("$,15Q5A(B" . "$,4 K\")\"$(B")
    ("$,15Q5B(B" . "$,4 K\")\"$(B")
    ("$,16)(B" . "\$,4\")\"L(B")
    ("$,16)5A(B" . "\$,4\")\"$(B")
    ("$,16)5B(B" . "\$,4\")\"$(B")
    ("$,15R(B" . "$,4 K\")\"@(B") 
    ("$,15R5A(B" . "$,4 K\")\"@\"(B&") 
    ("$,16*(B" . "\$,4\")\"@(B")
    ("$,16*5A(B" . "\$,4\")\"@\"(B&")
    ("$,15S(B" . "$,4 K\")\"D(B")
    ("$,15S5A(B" . "$,4 K\")\"D\"(B&")
    ("$,16+(B" . "\$,4\")\"D(B")
    ("$,16+5A(B" . "\$,4\")\"D\"(B&")
    ("$,15T(B" . "$,4 K\")\"H(B") 
    ("$,15T5A(B" . "$,4 K\")\"H\"(B&") 
    ("$,16,(B" . "\$,4\")\"H(B")
    ("$,16,5A(B" . "\$,4\")\"H\"(B&")
    ("$,16@(B" . "$,4 a\"(BQ") 
    ;;("$,16B(B" . nil)
    ;;("$,16A(B" . nil) 
    ;;("$,16C(B" . nil)

    ;; GRUTTALS
    ("$,15U(B" . "$,4 e\"(BR")
    ("$,15U6-(B" . "$,4 c(B")
    ("$,15U6-5p(B" . "$,4 g\"(BR")
    ("$,15U6-5d(B" . "$,4 h\"(BR")
    ("$,15U6-5w(B" . "$,4 i\"(B)")
    ("$,15U6-5w6-(B" . "$,4 i(B")

    ("$,15V(B" . "$,4 j\"(B)")
    ("$,15V6-(B" . "$,4 j(B")
    ("$,15V6-5p(B" . "$,4 l\"(B)")
    ("$,15V6-5p6-(B" . "$,4 l(B")

    ("$,15W(B" . "$,4 m\"(B)") 
    ("$,15W6-(B" . "$,4 m(B") 
    ("$,15W6-5p(B" . "$,4 o\"(B)")
    ("$,15W6-5p6-(B" . "$,4 o(B")

    ("$,15X(B" . "$,4 p\"(B)") 
    ("$,15X6-(B" . "$,4 p(B") 
    ("$,15X6-5p(B" . "$,4 q\"(B)") 
    ("$,15X6-5p6-(B" . "$,4 q(B") 

    ("$,15Y(B" . "$,4 r\"(BS")
    ;; PALATALS  
    ("$,15Z(B" . "$,4 s\"(B)") 
    ("$,15Z6-(B" . "$,4 s(B") 
    ("$,15Z6-5p(B" . "$,4 t\"(B)") 
    ("$,15Z6-5p6-(B" . "$,4 t(B")

    ("$,15[(B" . "$,4 u\"(BT") 

    ("$,15\(B" . "$,4 v\"(B)") 
    ("$,15\6-(B" . "$,4 v(B") 
    ("$,15\6-5p(B" . "$,4 x\"(B)") 
    ("$,15\6-5p6-(B" . "$,4 x(B") 
    ("$,15\6-5^(B" . "$,4 y\"(B)") 
    ("$,15\6-5^6-(B" . "$,4 y(B") 

    ("$,15](B" . "$,4 z\"(B)") 
    ("$,15]6-(B" . "$,4 z(B") 
    ("$,15]6-5p(B" . "$,4 {\"(B)") 
    ("$,15]6-5p6-(B" . "$,4 {(B") 

    ("$,15^(B" . "$,4 |\"(B)")
    ("$,15^6-(B" . "$,4 |(B")
    ;; CEREBRALS 
    ("$,15_(B" . "$,4 }\"(BU")
    ("$,15_6-5_(B" . "$,4 ~\"(BU")
    ("$,15_6-5`(B" . "$,4 \"(BU")

    ("$,15`(B" . "$,4! \"(BV") 
    ("$,15`6-5`(B" . "$,4!!\"(BV") 

    ("$,15a(B" . "$,4!\"\"W(B") 
    ("$,15a6-5a(B" . "$,4!$\"(BW") 
    ("$,15a6-5b(B" . "$,4!%\"(BW") 

    ("$,15b(B" . "$,4!&\"(BX") 

    ("$,15c(B" . "$,4!(\"(B)")
    ("$,15c6-(B" . "$,4!((B")
    ;; DENTALS   
    ("$,15d(B" . "$,4!)\"(B)") 
    ("$,15d6-(B" . "$,4!)(B") 
    ("$,15d6-5p(B" . "$,4!*\"(B)") 
    ("$,15d6-5p6-(B" . "$,4!*(B") 
    ("$,15d6-5d(B" . "$,4!+\"(B)") 
    ("$,15d6-5d6-(B" . "$,4!+(B") 

    ("$,15e(B" . "$,4!,\"(B)") 
    ("$,15e6-(B" . "$,4!,(B") 
    ("$,15e6-5p(B" . "$,4!-\"(B)") 
    ("$,15e6-5p6-(B" . "$,4!-(B") 

    ("$,15f(B" . "$,4!.\"(BY") 
    ("$,15f6#(B" . "$,4!/\"(BY")
    ("$,15f6-5p(B" . "$,4!0\"(BY")
    ("$,15f6-5f(B" . "$,4!1\"(BY")
    ("$,15f6-5g(B" . "$,4!2\"(BY")
    ("$,15f6-5n(B" . "$,4!3(B")
    ("$,15f6-5o(B" . "$,4!4(B")
    ("$,15f6-5u(B" . "$,4!5\"(BY")

    ("$,15g(B" . "$,4!6\"(B)") 
    ("$,15g6-(B" . "$,4!6(B") 
    ("$,15g6-5p(B" . "$,4!7\"(B)") 
    ("$,15g6-5p6-(B" . "$,4!7(B") 

    ("$,15h(B" . "$,4!8\"(B)") 
    ("$,15h6-(B" . "$,4!8(B") 
    ("$,15h6-5p(B" . "$,4!9\"(B)") 
    ("$,15h6-5p6-(B" . "$,4!9\"(B)") 
    ("$,15h6-5h(B" . "$,4!:\"(B)") 
    ("$,15h6-5h6-(B" . "$,4!:(B") 

    ("$,15i(B" . "$,4!8\"#\")(B")
    ;; LABIALS   
    ("$,15j(B" . "$,4!;\"(B)") 
    ("$,15j6-(B" . "$,4!;(B") 
    ("$,15j6-5p(B" . "$,4!<\"(B)") 
    ("$,15j6-5p6-(B" . "$,4!<(B") 

    ("$,15k(B" . "$,4!a\"(B[") 
    ("$,15k6-(B" . "$,4!=(B") 
    ("$,15k6-5p(B" . "$,4!c\"(B[") 

    ("$,15l(B" . "$,4!d\"(B)") 
    ("$,15l6-(B" . "$,4!d(B") 
    ("$,15l6-5p(B" . "$,4!e\"(B)") 
    ("$,15l6-5p6-(B" . "$,4!e(B") 

    ("$,15m(B" . "$,4!f\"(B)") 
    ("$,15m6-(B" . "$,4!f(B") 
    ("$,15m6-5p(B" . "$,4!g\"(B)") 
    ("$,15m6-5p6-(B" . "$,4!g(B") 

    ("$,15n(B" . "$,4!h\"(B)")
    ("$,15n6-(B" . "$,4!h(B")
    ("$,15n6-5p(B" . "$,4!i\"(B)")
    ("$,15n6-5p6-(B" . "$,4!i(B")
    ;; SEMIVOWELS
    ("$,15o(B" . "$,4!j\"(B)") 
    ("$,15o6-(B" . "$,4!j(B") 
    ("$,15o6-5p(B" . "$,4!k\"(B)") 
    ("$,15o6-5p6-(B" . "$,4!k(B") 
    ("$,16-5o(B" . "$,4!l(B") ;; when every ohter lig. fails.

    ("$,15p(B" . "$,4!n\"(BW") 
    ;; ("$,15p6-(B" . "\$,4"'(B") ;; special case.  only the topmost pos.
    ("$,15q(B" . "$,4!n\"#\"W(B") 
    ("$,15q6-(B" . "$,4!m(B") ;; IS 13194 speical rule.
    ("$,15p6!(B" . "$,4!o\"(B[") 
    ("$,15p6"(B" . "$,4!p\"(B\\") 

    ("$,15r(B" . "$,4!q\"(B)") 
    ("$,15r6-(B" . "$,4!q(B") 
    ("$,15s(B" . "$,4!s(B") 
    ("$,15s6-(B" . "$,4!r(B") 
    ("$,15t(B" . "$,4!s\"(B#")
    ("$,15t6-(B" . "$,4!r\"(B#")

    ("$,15u(B" . "$,4!t\"(B)")
    ("$,15u6-(B" . "$,4!t(B")
    ("$,15u6-5p(B" . "$,4!u\"(B)")
    ("$,15u6-5p6-(B" . "$,4!u(B")
    ;; SIBILANTS 
    ("$,15v(B" . "$,4!v\"(B)") 
    ("$,15v6-(B" . "$,4!v(B")
    ("$,15v6-5u(B" . "$,4!w\"(B)")
    ("$,15v6-5u6-(B" . "$,4!w(B")
    ("$,15v6-5p(B" . "$,4!x\"(B)")
    ("$,15v6-5p6-(B" . "$,4!x(B")

    ("$,15w(B" . "$,4!y\"(B)")
    ("$,15w6-(B" . "$,4!y(B")
    ("$,15x(B" . "$,4!z\"(B)")
    ("$,15x6-(B" . "$,4!z(B")
    ("$,15x6-5p(B" . "$,4!{\"(B)")
    ("$,15x6-5p6-(B" . "$,4!{(B")

    ("$,15y(B" . "$,4!}(B")
    ("$,15y6-(B" . "$,4!|(B")
    ("$,15y6#(B" . "$,4!~(B")
    ("$,15y6-5p(B" . "$,4!(B")
    ("$,15y6-5n(B" . "$,4\"(B ")
    ("$,15y6-5o(B" . "$,4\"(B!")
    ;; NUKTAS    
    ("$,168(B" . "$,4 f\"R\"S(B")
    ("$,1686-(B" . "$,4 d(B") 
    ("$,169(B" . "$,4 k\"(B)") 
    ("$,1696-(B" . "$,4 k(B") 
    ("$,16:(B" . "$,4 n\"(B)") 
    ("$,16:6-(B" . "$,4 n(B") 
    ("$,16;(B" . "$,4 w\"(B)") 
    ("$,16;6-(B" . "$,4 w(B") 
    ("$,16<(B" . "$,4!#\"(BW") 
    ("$,16=(B" . "$,4!'\"(BX") 
    ("$,16>(B" . "$,4!b\"(B[") 
    ("$,16>6-(B" . "$,4!>(B") 
    ("$,16?(B" . "$,4!j\"#\")(B")
    ;; misc modifiers.
    ("$,15A(B" . "\$,4\"(B$")
    ("$,15B(B" . "\$,4\"(B&") 
    ("$,15C(B" . "$,4 F(B")
    ("$,15|(B" . "$,4\"(B#")
    ("$,15}(B" . "$,4 E(B")
    ("$,16-(B" . "$,4\"\"(B")
    ("$,16-5p(B" . "$,4\"(B%") ;; following "r"
    ;; ("$,160(B" . "$,4 D(B") 
    ;; ("$,16D(B" . "$,4 J(B")
    ;; ("$,16F(B" . "") 
    ;; ("$,16G(B" . "") 
    ;; ("$,16H(B" . "") 
    ;; ("$,16I(B" . "") 
    ;; ("$,16J(B" . "") 
    ;; ("$,16K(B" . "") 
    ;; ("$,16L(B" . "") 
    ;; ("$,16M(B" . "") 
    ;; ("$,16N(B" . "") 
    ;; ("$,16O(B" . "")
    )
  "Devanagari characters to glyphs conversion table.  
Default value contains only the basic rules.  You may add your own
preferred rule from the sanskrit fonts."  )

(defvar dev-char-glyph-hash
  (let* ((hash (makehash 'equal)))
    (mapc (function (lambda (x) (puthash (car x) (cdr x) hash)))
	  dev-char-glyph)
    hash))

(defvar dev-char-glyph-regexp
  (regexp-of-hashtbl-keys dev-char-glyph-hash))

;; glyph-to-glyph conversion table.
;; it is supposed that glyphs are ordered in 
;;   [consonant/nukta] - [matra/halant] - [preceding-r] - [anuswar].

(defvar dev-glyph-glyph
  '(("\$,4\"(B'\$,4\"(B&" . "\$,4\"(B(")
    ("\$,4\"(B'\$,4\"(B$" . "\$,4\"(B(")
    ("$,4\"(B*\$,4\"(B&" . "$,4\"(B+")
    ("$,4\"(B*\$,4\"(B'" . "$,4\"(B,")
    ("$,4\"(B*\$,4\"(B'\$,4\"(B&" . "$,4\"(B-")
    ("$,4\"(B2\$,4\"(B&" . "$,4\"(B3")
    ("$,4\"(B2\$,4\"(B'" . "$,4\"(B4")
    ("$,4\"(B2\$,4\"(B'\$,4\"(B&" . "$,4\"(B5")
    ("$,4\"(B#\$,4\"(B6" . "$,4\"(B7")
    ("$,4\"(B%\$,4\"(B6" . "$,4\"(B8")
    ;;("$,4\"(B6" . "$,4\"(B9")
    ("$,4\"(B#\$,4\"(B:" . "$,4\"(B;")
    ("$,4\"(B%\$,4\"(B:" . "$,4\"(B<")
    ;;("$,4\"(B:" . "$,4\"(B=")
    ("\$,4\"(B@\$,4\"(B&" . "\$,4\"(BA")
    ("\$,4\"(B@\$,4\"(B'" . "\$,4\"(BB")
    ("\$,4\"(B@\$,4\"(B'\$,4\"(B&" . "\$,4\"(BC")
    ("\$,4\"(BD\$,4\"(B&" . "\$,4\"(BE")
    ("\$,4\"(BD\$,4\"(B'" . "\$,4\"(BF")
    ("\$,4\"(BD\$,4\"(B'\$,4\"(B&" . "\$,4\"(BG")
    ("\$,4\"(BH\$,4\"(B&" . "\$,4\"(BI")
    ("\$,4\"(BH\$,4\"(B'" . "\$,4\"(BJ")
    ("\$,4\"(BH\$,4\"(B'\$,4\"(B&" . "\$,4\"(BK")
    ("\$,4\"(BL\$,4\"(B&" . "\$,4\"(BM")
    ("\$,4\"(BL\$,4\"(B'" . "\$,4\"(BN")
    ("\$,4\"(BL\$,4\"(B'\$,4\"(B&" . "\$,4\"(BO")
    ))
(defvar dev-glyph-glyph-hash
  (let* ((hash (makehash 'equal)))
    (mapc (function (lambda (x) (puthash (car x) (cdr x) hash)))
	  dev-glyph-glyph)
    hash))
(defvar dev-glyph-glyph-regexp
  (regexp-of-hashtbl-keys dev-glyph-glyph-hash))


;; yet another glyph-to-glyph conversions.
(defvar dev-glyph-glyph-2
  '(("$,4\"(B*" . "$,4\"(B.")
    ("$,4\"(B+" . "$,4\"(B/")
    ("$,4\"(B," . "$,4\"(B0")
    ("$,4\"(B-" . "$,4\"(B1")))
(defvar dev-glyph-glyph-2-hash
  (let* ((hash (makehash 'equal)))
    (mapc (function (lambda (x) (puthash (car x) (cdr x) hash)))
	  dev-glyph-glyph-2)
    hash))
(defvar dev-glyph-glyph-2-regexp
  (regexp-of-hashtbl-keys dev-glyph-glyph-2-hash))


(defun dev-charseq (from &optional to)
  (if (null to) (setq to from))
  (mapcar (function (lambda (x) (indian-glyph-char x 'devanagari)))
          (range from to)))

(defvar dev-glyph-cvn
  (append 
   (dev-charseq #x2b)
   (dev-charseq #x3c #xc1)
   (dev-charseq #xc3))
  "Devanagari Consonants/Vowels/Nukta Glyphs")

(defvar dev-glyph-space
  (dev-charseq #xf0 #xfe)
  "Devanagari Spacing Glyphs")

(defvar dev-glyph-right-modifier
  (append 
   (dev-charseq #xc9)
   (dev-charseq #xd2 #xd5))
  "Devanagari Modifiers attached at the right side.")

(defvar dev-glyph-right-modifier-regexp
  (concat "[" dev-glyph-right-modifier "]"))

(defvar dev-glyph-left-matra
  (dev-charseq #xca #xd1)
  "Devanagari Matras attached at the left side.")

(defvar dev-glyph-top-matra
  (dev-charseq #xe0 #xef)
  "Devanagari Matras attached at the top side.")

(defvar dev-glyph-bottom-modifier
  (append 
   (dev-charseq #xd6 #xdf)
   (dev-charseq #xc2))
  "Devanagari Modifiers attached at the bottom.")

(defvar dev-glyph-order
  `((,dev-glyph-cvn . 1)
    (,dev-glyph-space . 2)
    (,dev-glyph-right-modifier . 3)
    (,dev-glyph-left-matra . 3) ;; processed by reference point.
    (,dev-glyph-top-matra . 4)
    (,(dev-charseq #xc7 #xc8) . 5)
    (,(dev-charseq #xc6) . 6)
    (,(dev-charseq #xc5) . 7)
    (,dev-glyph-bottom-modifier . 8)))

(mapc 
 (function (lambda (x)
   (mapc 
     (function (lambda (y)
       (put-char-code-property y 'composition-order (cdr x))))
     (car x))))
  dev-glyph-order)

(mapc
  (function (lambda (x)
    (put-char-code-property x 'reference-point '(3 . 5))))
 dev-glyph-left-matra)

(defun devanagari-compose-syllable-string (string)
  (with-temp-buffer
    (insert (decompose-string string))
    (devanagari-compose-syllable-region (point-min) (point-max))
    (buffer-string)))

(defun devanagari-compose-syllable-region (from to)
  "Compose devanagari syllable in region FROM to TO."
  (let ((glyph-str nil) (cons-num 0) glyph-str-list
        (last-halant nil) (preceding-r nil) (last-modifier nil) 
        (last-char (char-before to)) match-str
        glyph-block split-pos)
    (save-excursion
      (save-restriction
          ;;; *** char-to-glyph conversion ***
        ;; Special rule 1. -- Last halant must be preserved.
        (if (eq last-char ?$,16-(B)
            (progn
              (setq last-halant t)
              (narrow-to-region from (1- to)))
          (narrow-to-region from to)
          ;; note if the last char is modifier.
          (if (or (eq last-char ?$,15A(B) (eq last-char ?$,15B(B))
              (setq last-modifier t)))
        (goto-char (point-min))
        ;; Special rule 2. -- preceding "r halant" must be modifier.
        (when (looking-at "$,15p6-(B.")
          (setq preceding-r t)
          (goto-char (+ 2 (point))))
        ;; translate the rest characters into glyphs
        (while (re-search-forward dev-char-glyph-regexp nil t)
          (setq match-str (match-string 0))
          (setq glyph-str 
                (concat glyph-str
                        (gethash match-str dev-char-glyph-hash)))
          ;; count the number of consonant-glyhs.
          (if (string-match devanagari-consonant match-str)
              (setq cons-num (1+ cons-num))))
        ;; preceding-r must be attached before the anuswar if exists.
        (if preceding-r 
            (if last-modifier
                (setq glyph-str (concat (substring glyph-str 0 -1) 
                                        "$,4\"(B'" (substring glyph-str -1)))
              (setq glyph-str (concat glyph-str "$,4\"(B'"))))
        (if last-halant (setq glyph-str (concat glyph-str "$,4\"\"(B")))
          ;;; *** glyph-to-glyph conversion ***
        (when (string-match dev-glyph-glyph-regexp glyph-str)
          (setq glyph-str
                (replace-match (gethash (match-string 0 glyph-str) 
                                        dev-glyph-glyph-hash)
                               nil t glyph-str))
          (if (and (> cons-num 1)
                   (string-match dev-glyph-glyph-2-regexp glyph-str))
              (setq glyph-str
                    (replace-match (gethash (match-string 0 glyph-str)
                                            dev-glyph-glyph-2-hash)
                                   nil t glyph-str))))
          ;;; *** glyph reordering ***
        (while (setq split-pos (string-match "$,4\"\"(B\\|.$" glyph-str))
          (setq glyph-block (substring glyph-str 0 (1+ split-pos)))
          (setq glyph-str (substring glyph-str (1+ split-pos)))
          (setq 
           glyph-block 
           (if (string-match dev-glyph-right-modifier-regexp glyph-block)
               (sort (string-to-list glyph-block)
                     (function (lambda (x y)
                        (< (get-char-code-property x 'composition-order)
                           (get-char-code-property y 'composition-order)))))
             (sort (string-to-list glyph-block)
                   (function (lambda (x y)
                      (let ((xo (get-char-code-property x 'composition-order))
                            (yo (get-char-code-property y 'composition-order)))
                        (if (= xo 2) nil (if (= yo 2) t (< xo yo)))))))))
          (setq glyph-str-list (nconc glyph-str-list glyph-block)))
          ;; concatenate and attach reference-points.
        (setq glyph-str
              (cdr 
               (apply 
                'nconc 
                (mapcar 
                 (function (lambda (x) 
                   (list
                    (or (get-char-code-property x 'reference-point)
                    '(5 . 3) ;; default reference point.
                     )
                    x)))
                 glyph-str-list))))))
      (compose-region from to glyph-str)))

(provide 'devan-util)