1 ;;; tv-util.el --- support for Tai Viet -*- coding: utf-8 -*-
3 ;; Copyright (C) 2007, 2008, 2009, 2010, 2011
4 ;; National Institute of Advanced Industrial Science and Technology (AIST)
5 ;; Registration Number H13PRO009
7 ;; Keywords: multilingual, Tai Viet, i18n
9 ;; This file is part of GNU Emacs.
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 of the License, or
14 ;; (at your option) any later version.
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.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
26 ;; Regexp matching with a sequence of Tai Viet characters.
27 (defconst tai-viet-re "[\xaa80-\xaac2\xaadb-\xaadf]+")
29 ;; Char-table of information about glyph type of Tai Viet characters.
30 (defconst tai-viet-glyph-info
31 (let ((table (make-char-table nil))
32 (specials '((right-overhang . "ꪊꪋꪌꪍꪏꪓꪖꪜꪞꪡꪤꪨ")
34 (combining-vowel . "ꪴꪰꪲꪳꪷꪸꪾ")
35 (combining-tone . "꪿꫁")
37 ;; Set all TaiViet characters to t.
38 (set-char-table-range table (cons #xaa80 #xaac2) t)
39 (set-char-table-range table (cons #xaadb #xaadf) t)
40 ;; Overwrite it for special characters.
41 (dolist (elt specials)
42 (let ((category (car elt))
44 (dotimes (i (length chars))
45 (aset table (aref chars i) category))))
48 (defun tai-viet-compose-string (from to string)
49 "Compose Tai Viet characters in STRING between indices FROM and TO."
50 (let* ((ch (aref string from))
51 (info (aref tai-viet-glyph-info ch))
53 (if (eq info 'non-spacing)
54 (compose-string string from (1+ from) (string ch ?\t)))
55 (setq from (1+ from) prev-info info)
56 (while (and (< from to)
57 (>= #xaa80 (setq ch (aref string from)))
59 (setq info (aref tai-viet-glyph-info ch))
60 (if (and (eq info 'non-spacing)
61 (eq prev-info 'non-spacing))
62 (compose-string from (1+ from) (string ?\t ch)))
63 (setq from (1+ from) prev-info info))
64 (if (eq info 'right-overhang)
65 (compose-string string (1- from) from (string ch ?\t)))
68 (defun tai-viet-compose-region (from to)
69 "Compose Tai Viet characters in the region between FROM and TO."
70 (decompose-region from to)
71 (let ((normal-rule '(Br . Bl))
72 (tone-rule '(tr . bl))
74 ch info pos components overhang)
77 (setq ch (char-after from)
78 info (aref tai-viet-glyph-info ch)))
83 (if (memq info '(combining-vowel combining-tone))
85 ;; Display this as a spacing glyph.
86 (compose-region (1- from) from (string ?\t ch))
91 overhang (if (eq info 'right-overhang)
93 (if (and (not prev-viet) (eq info 'left-overhang))
98 (setq ch (char-after from)
99 info (aref tai-viet-glyph-info ch)))
100 (if (memq info '(combining-vowel combining-tone))
103 (list components normal-rule ch)
107 (setq ch (char-after from)
108 info (aref tai-viet-glyph-info ch))
109 (eq info 'combining-tone))
110 (setq components (nconc components
113 (if (eq overhang 'left-overhang)
114 (setq components (cons ?\t
115 (cons normal-rule components)))
116 (if (and (eq overhang 'right-overhang)
118 (setq components (nconc components
119 (list normal-rule ?\t)))))
120 (compose-region pos from components))
121 (if (eq overhang 'left-overhang)
122 (compose-region pos from (string ?\t components))))
123 (if (eq overhang 'left-overhang)
124 (compose-region pos from (string ?\t components))
125 (if (and (eq overhang 'right-overhang) (>= from to))
126 (compose-region pos from (string components ?\t))))))))
131 (defun tai-viet-composition-function (from to font-object string)
133 (if (string-match tai-viet-re string from)
134 (tai-viet-compose-string from (match-end 0) string))
136 (if (looking-at tai-viet-re)
137 (tai-viet-compose-region from (match-end 0)))))
140 (provide 'tai-viet-util)