144 lines
4.7 KiB
EmacsLisp
144 lines
4.7 KiB
EmacsLisp
;;; tv-util.el --- support for Tai Viet -*- lexical-binding: t; -*-
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;; Copyright (C) 2007, 2008, 2009, 2010, 2011
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;; National Institute of Advanced Industrial Science and Technology (AIST)
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;; Registration Number H13PRO009
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;; Keywords: multilingual, Tai Viet, i18n
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;;; Code:
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(defconst tai-viet-re "[\xaa80-\xaac2\xaadb-\xaadf]+"
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"Regexp matching with a sequence of Tai Viet characters.")
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(defconst tai-viet-glyph-info
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(let ((table (make-char-table nil))
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(specials '((right-overhang . "ꪊꪋꪌꪍꪏꪓꪖꪜꪞꪡꪤꪨ")
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(left-overhang . "ꫂ")
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(combining-vowel . "ꪴꪰꪲꪳꪷꪸꪾ")
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(combining-tone . "꪿꫁")
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(misc . "-"))))
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;; Set all TaiViet characters to t.
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(set-char-table-range table (cons #xaa80 #xaac2) t)
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(set-char-table-range table (cons #xaadb #xaadf) t)
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;; Overwrite it for special characters.
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(dolist (elt specials)
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(let ((category (car elt))
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(chars (cdr elt)))
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(dotimes (i (length chars))
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(aset table (aref chars i) category))))
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table)
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"Char-table of information about glyph type of Tai Viet characters.")
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(defun tai-viet-compose-string (from to string)
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"Compose Tai Viet characters in STRING between indices FROM and TO."
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(let* ((ch (aref string from))
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(info (aref tai-viet-glyph-info ch))
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prev-info)
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(if (eq info 'non-spacing)
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(compose-string string from (1+ from) (string ch ?\t)))
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(setq from (1+ from) prev-info info)
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(while (and (< from to)
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(>= #xaa80 (setq ch (aref string from)))
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(<= #xaaDF ch))
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(setq info (aref tai-viet-glyph-info ch))
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(if (and (eq info 'non-spacing)
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(eq prev-info 'non-spacing))
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(compose-string from (1+ from) (string ?\t ch)))
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(setq from (1+ from) prev-info info))
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(if (eq info 'right-overhang)
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(compose-string string (1- from) from (string ch ?\t)))
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from))
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(defun tai-viet-compose-region (from to)
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"Compose Tai Viet characters in the region between FROM and TO."
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(decompose-region from to)
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(let ((normal-rule '(Br . Bl))
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(tone-rule '(tr . bl))
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(prev-viet nil)
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ch info pos components overhang)
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(while (< from to)
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(or ch
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(setq ch (char-after from)
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info (aref tai-viet-glyph-info ch)))
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(setq from (1+ from))
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(if (not info)
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(setq prev-viet nil
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ch nil)
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(if (memq info '(combining-vowel combining-tone))
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(progn
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;; Display this as a spacing glyph.
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(compose-region (1- from) from (string ?\t ch))
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(setq prev-viet t
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ch nil))
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(setq pos (1- from)
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components ch
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overhang (if (eq info 'right-overhang)
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'right-overhang
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(if (and (not prev-viet) (eq info 'left-overhang))
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'left-overhang))
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prev-viet t
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ch nil)
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(if (and (< from to)
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(setq ch (char-after from)
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info (aref tai-viet-glyph-info ch)))
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(if (memq info '(combining-vowel combining-tone))
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(progn
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(setq components
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(list components normal-rule ch)
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from (1+ from)
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ch nil)
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(if (and (< from to)
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(setq ch (char-after from)
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info (aref tai-viet-glyph-info ch))
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(eq info 'combining-tone))
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(setq components (nconc components
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(list tone-rule ch))
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from (1+ from)))
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(if (eq overhang 'left-overhang)
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(setq components (cons ?\t
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(cons normal-rule components)))
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(if (and (eq overhang 'right-overhang)
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(>= from to))
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(setq components (nconc components
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(list normal-rule ?\t)))))
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(compose-region pos from components))
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(if (eq overhang 'left-overhang)
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(compose-region pos from (string ?\t components))))
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(if (eq overhang 'left-overhang)
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(compose-region pos from (string ?\t components))
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(if (and (eq overhang 'right-overhang) (>= from to))
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(compose-region pos from (string components ?\t))))))))
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from))
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;;;###autoload
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(defun tai-viet-composition-function (from _to _font-object string _direction)
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(if string
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(if (string-match tai-viet-re string from)
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(tai-viet-compose-string from (match-end 0) string))
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(goto-char from)
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(if (looking-at tai-viet-re)
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(tai-viet-compose-region from (match-end 0)))))
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(provide 'tai-viet-util)
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;;; tv-util.el ends here
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