Package: emacs;
Reported by: समीर सिंह Sameer Singh <lumarzeli30 <at> gmail.com>
Date: Wed, 11 May 2022 15:03:02 UTC
Severity: normal
Tags: patch
Done: Eli Zaretskii <eliz <at> gnu.org>
Bug is archived. No further changes may be made.
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From: समीर सिंह Sameer Singh <lumarzeli30 <at> gmail.com> To: Eli Zaretskii <eliz <at> gnu.org> Cc: 55370 <at> debbugs.gnu.org Subject: bug#55370: [PATCH] Add support for the Syloti Nagri script Date: Thu, 12 May 2022 22:20:15 +0530
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Ah! I think I understand now.
Since Emacs had pre defined rules for these characters, they were rendering
fine without my input, but when I had included them in range,
a new rule had to be defined for them, because the previous ones were
overwritten.
For example, this is correct now isn't it?
;; Syloti Nagri composition rules
(let ((consonant "[\xA807-\xA80A\xA80C-\xA822]")
(independent-vowel "[\xA800\xA801\xA803-\xA805]")
(vowel "[\xA802\xA823-\xA827]")
(nasal "[\xA80B]")
(virama "[\xA806\xA82C]"))
(set-char-table-range composition-function-table
'(#xA802 . #xA82C)
(list (vector
;; Consonant conjunct based syllables
(concat consonant "\\(?:" virama consonant
"\\)+"
vowel "?" nasal "?")
1 'font-shape-gstring)
(vector
;; Vowels based syllables
(concat independent-vowel consonant "?"
virama "?"
vowel "?" nasal "?")
1 'font-shape-gstring))))
Here I have included the nasal sign, virama and vowel sign in the range.
I have also added a rule for independent vowels with consonants, virama,
vowel signs and nasal signs so that emacs does not hang, when they appear
together.
On Thu, May 12, 2022 at 9:59 PM Eli Zaretskii <eliz <at> gnu.org> wrote:
> > From: समीर सिंह Sameer Singh <lumarzeli30 <at> gmail.com>
> > Date: Thu, 12 May 2022 20:36:49 +0530
> > Cc: 55370 <at> debbugs.gnu.org
> >
> > For example in tirhuta, when I do this:
> >
> > ;; Tirhuta composition rules
> > (let ((consonant "[\x1148F-\x114AF]")
> > (nukta "\x114C3")
> > (independent-vowel "[\x11481-\x1148E]")
> > (vowel "[\x114B0-\x114BE]")
> > (nasal "[\x114BF\x114C0]")
> > (virama "\x114C2"))
> > (set-char-table-range composition-function-table
> > '(#x114B0 . #x114BE)
> > (list (vector
> > ;; Consonant based syllables
> > (concat consonant nukta "?\\(?:" virama
> > consonant nukta "?\\)*\\(?:"
> > virama "\\|" vowel "*" nukta "?"
> > nasal "?\\)")
> > 1 'font-shape-gstring))))
> >
> > Notice here, the nasal sign is not included in the range.
> > And then I type: 𑒅𑓀 𑒆𑒿
> > It is rendered correctly
>
> It is rendered correctly because your rule isn't used.
>
> The rule
>
> '(#x114B0 . #x114BE)
> (list (vector
> ;; Consonant based syllables
> (concat consonant nukta "?\\(?:"
> virama consonant nukta "?\\)* \\(?:"
> virama "\\|" vowel "*" nukta "?"
> nasal "?\\)")
> 1 'font-shape-gstring))))
>
> says this:
>
> . find a character C between #x114B0 and #x114BE
> . see if the characters starting one character before C match the
> above regexp
> . if they match, compose them
>
> But your text doesn't include any characters in the range
> [\x114B0-\x114BE], so the above rule will never match anything, and
> will not cause any composition.
>
> You see the characters composed because the second character in each
> par, #x114C0 and #x114BF, is a combining accent, and for those we have
> a catch-all rule in composite.el:
>
> (when unicode-category-table
> (let ((elt `([,(purecopy "\\c.\\c^+") 1 compose-gstring-for-graphic]
> [nil 0 compose-gstring-for-graphic])))
> (map-char-table
> #'(lambda (key val)
> (if (memq val '(Mn Mc Me))
> (set-char-table-range composition-function-table key elt)))
> unicode-category-table))
>
>
> > But when I do:
> >
> > ;; Tirhuta composition rules
> > (let ((consonant "[\x1148F-\x114AF]")
> > (nukta "\x114C3")
> > (independent-vowel "[\x11481-\x1148E]")
> > (vowel "[\x114B0-\x114BE]")
> > (nasal "[\x114BF\x114C0]")
> > (virama "\x114C2"))
> > (set-char-table-range composition-function-table
> > '(#x114B0 . #x114C0)
> > (list (vector
> > ;; Consonant based syllables
> > (concat consonant nukta "?\\(?:" virama
> > consonant nukta "?\\)*\\(?:"
> > virama "\\|" vowel "*" nukta "?"
> > nasal "?\\)")
> > 1 'font-shape-gstring))))
> > The range now has the nasal signs.
> > And then type the above characters: 𑒅𑓀 𑒆𑒿
> > They are not rendered correctly
>
> In this case, the characters that trigger examination of the
> composition rules, #x114C0 and #x114BF, _are_ in the range
> '(#x114B0 . #x114C0). However, the preceding characters, #x11484 and
> #x11486, are independent-vowel's, and there are no independent-vowel
> in the regexp. So again, the rules will never match. Except that now
> you also replaced the default rule we have for the combining accents,
> so what worked before no longer does.
>
> > But when I include their composition rules:
> >
> > ;; Tirhuta composition rules
> > (let ((consonant "[\x1148F-\x114AF]")
> > (nukta "\x114C3")
> > (independent-vowel "[\x11481-\x1148E]")
> > (vowel "[\x114B0-\x114BE]")
> > (nasal "[\x114BF\x114C0]")
> > (virama "\x114C2"))
> > (set-char-table-range composition-function-table
> > '(#x114B0 . #x114C0)
> > (list (vector
> > ;; Consonant based syllables
> > (concat consonant nukta "?\\(?:" virama
> > consonant nukta "?\\)*\\(?:"
> > virama "\\|" vowel "*" nukta "?"
> > nasal "?\\)")
> > 1 'font-shape-gstring)
> > (vector
> > ;; Nasal vowels
> > (concat independent-vowel nasal "?")
> > 1 'font-shape-gstring))))
> >
> > They are now once more rendered correctly.
>
> As expected, see above: now you do have a regexp that can match, it's
> this one:
>
> (concat independent-vowel nasal "?")
>
> I hope you now understand how to fix the rules. If not, please ask
> more questions and show more examples.
>
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