;;; misc-lang.el --- support for miscellaneous languages (characters) -*- lexical-binding: t; -*-
;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
;; 2005, 2006, 2007, 2008, 2009, 2010, 2011
;; National Institute of Advanced Industrial Science and Technology (AIST)
;; Registration Number H14PRO021
;; Keywords: multilingual, character set, coding system
;; 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 3 of the License, 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. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; IPA (International Phonetic Alphabet)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(set-language-info-alist
"IPA" '((charset . (ipa))
(coding-priority utf-8)
(coding-system utf-8)
(input-method . "ipa")
(nonascii-translation . ipa)
(documentation . "\
IPA is International Phonetic Alphabet for English, French, German
and Italian.")))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Arabic
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define-coding-system 'iso-8859-6
"ISO-8859-6 based encoding (MIME:ISO-8859-6)."
:coding-type 'charset
:mnemonic ?6
:charset-list '(iso-8859-6)
:mime-charset 'iso-8859-6)
(define-coding-system 'windows-1256
"windows-1256 (Arabic) encoding (MIME: WINDOWS-1256)"
:coding-type 'charset
:mnemonic ?A
:charset-list '(windows-1256)
:mime-charset 'windows-1256)
(define-coding-system-alias 'cp1256 'windows-1256)
(set-language-info-alist
"Arabic" '((charset unicode)
(coding-system utf-8 iso-8859-6 windows-1256)
(coding-priority utf-8 iso-8859-6 windows-1256)
(input-method . "arabic")
(sample-text . "Arabic السّلام عليكم")
(documentation . "Bidirectional editing is supported.")))
(set-language-info-alist
"Persian" '((charset unicode)
(coding-system utf-8 iso-8859-6 windows-1256)
(coding-priority utf-8 iso-8859-6 windows-1256)
(input-method . "farsi-transliterate-banan")
(sample-text . "Persian فارسی")
(documentation . "Bidirectional editing is supported.")))
(defcustom arabic-shaper-ZWNJ-handling nil
"How to handle ZWMJ in Arabic text rendering.
This variable controls the way to handle a glyph for ZWNJ
returned by the underling shaping engine.
The default value is nil, which means that the ZWNJ glyph is
displayed as is.
If the value is `absorb', ZWNJ is absorbed into the previous
grapheme cluster, and not displayed.
If the value is `as-space', the glyph is displayed by a
thin (i.e. 1-dot width) space."
:group 'mule
:version "26.1"
:type '(choice
(const :tag "default" nil)
(const :tag "as space" as-space)
(const :tag "absorb" absorb))
:set (lambda (sym val)
(set-default sym val)
(clear-composition-cache)))
;; Record error in arabic-change-gstring.
(defvar arabic-shape-log nil)
(defun arabic-shape-gstring (gstring direction)
(setq gstring (font-shape-gstring gstring direction))
(condition-case err
(when arabic-shaper-ZWNJ-handling
(let ((font (lgstring-font gstring))
(i 1)
(len (lgstring-glyph-len gstring))
(modified nil))
(while (< i len)
(let ((glyph (lgstring-glyph gstring i)))
(when (eq (lglyph-char glyph) #x200c)
(cond
((eq arabic-shaper-ZWNJ-handling 'as-space)
(if (> (- (lglyph-rbearing glyph) (lglyph-lbearing glyph)) 0)
(let ((space-glyph (aref (font-get-glyphs font 0 1 " ") 0)))
(when space-glyph
(lglyph-set-code glyph (aref space-glyph 3))
(lglyph-set-width glyph (aref space-glyph 4)))))
(lglyph-set-adjustment glyph 0 0 1)
(setq modified t))
((eq arabic-shaper-ZWNJ-handling 'absorb)
(let ((prev (lgstring-glyph gstring (1- i))))
(lglyph-set-from-to prev (lglyph-from prev) (lglyph-to glyph))
(setq gstring (lgstring-remove-glyph gstring i))
(setq len (1- len)))
(setq modified t)))))
(setq i (1+ i)))
(if modified
(lgstring-set-id gstring nil))))
(error (push err arabic-shape-log)))
gstring)
(set-char-table-range
composition-function-table
'(#x600 . #x74F)
(list (vector "[\u200C\u200D][\u0600-\u074F\u200C\u200D]+"
1 #'arabic-shape-gstring)
(vector "[\u0600-\u074F\u200C\u200D]+"
0 #'arabic-shape-gstring)))
;; The Egyptian Hieroglyph Format Controls were introduced in Unicode
;; Standard v12.0. Apparently, they are not yet well supported in
;; existing fonts, as of late 2020. But there's no reason for us not
;; to be ready for when they will be!
;; The below is needed to support the arrangement of the Egyptian
;; Hieroglyphs in "quadrats", as directed by the format controls,
;; which specify how the hieroglyphs should be joined horizontally and
;; vertically.
(defun egyptian-shape-grouping (gstring direction)
(if (= (lgstring-char gstring 0) #x13437)
(let ((nchars (lgstring-char-len gstring))
(i 1)
(nesting 1)
ch)
;; Find where this group ends.
(while (and (< i nchars) (> nesting 0))
(setq ch (lgstring-char gstring i))
(cond
((= ch #x13437)
(setq nesting (1+ nesting)))
((= ch #x13438)
(setq nesting (1- nesting))))
(setq i (1+ i)))
(when (zerop nesting)
;; Make a new gstring from the characters that constitute a
;; complete nested group.
(let ((new-header (make-vector (1+ i) nil))
(new-gstring (make-vector (+ i 2) nil)))
(aset new-header 0 (lgstring-font gstring))
(dotimes (j i)
(aset new-header (1+ j) (lgstring-char gstring j))
(lgstring-set-glyph new-gstring j (lgstring-glyph gstring j)))
(lgstring-set-header new-gstring new-header)
(font-shape-gstring new-gstring direction))))))
(let ((hieroglyph "[\U00013000-\U0001342F]"))
;; HORIZONTAL/VERTICAL JOINER and INSERT AT.../OVERLAY controls
(set-char-table-range
composition-function-table
'(#x13430 . #x13436)
(list (vector (concat hieroglyph "[\U00013430-\U00013436]" hieroglyph)
;; We use font-shape-gstring so that, if the font
;; doesn't support these controls, the glyphs are
;; displayed individually, and not as a single
;; grapheme cluster.
1 #'font-shape-gstring)))
;; Grouping controls
(set-char-table-range
composition-function-table
#x13437
(list (vector "\U00013437[\U00013000-\U0001343F]+"
0 #'egyptian-shape-grouping)))
;; "Normal" hieroglyphs, for fonts that don't support the above
;; controls, but do shape sequences of hieroglyphs without the
;; controls.
;; FIXME: As of late 2021, Egyptian Hieroglyph Format Controls are
;; not yet supported in existing fonts and/or shaping engines, but
;; some fonts do provide ligatures with which texts in Egyptian
;; Hieroglyphs are correctly displayed. If and when these format
;; controls are supported, as described in section 11.4 "Egyptian
;; Hieroglyphs" of the Unicode Standard, the five lines below (which
;; allow composition of hieroglyphs without formatting controls
;; around) can be removed, and the entry in etc/HELLO can be
;; restored to:
;; Egyptian Hieroglyphs (𓂋𓏤𓈖𓆎𓅓𓏏𓊖) 𓅓𓊵𓏏𓊪, 𓇍𓇋𓂻𓍘𓇋
(set-char-table-range
composition-function-table
'(#x13000 . #x1342E)
(list (vector "[\U00013000-\U0001342E]+"
0 #'font-shape-gstring))))
(provide 'misc-lang)
;;; misc-lang.el ends here