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RE: [UAX29] i18n comment 8: Conjunct clusters

From: Richard Ishida <ishida@w3.org>
Date: Fri, 7 Mar 2008 16:46:39 -0000
To: "'Mark Davis'" <mark.davis@icu-project.org>
Cc: <public-i18n-core@w3.org>
Message-ID: <007f01c88072$d10434c0$730c9e40$@org>

I don't think we can fix this with wording in the UAX.

It seems we would need to investigate whether it makes sense to treat Khmer
and Myanmar as a script (like Thai and Lao) that merits exceptional rules
for certain character combinations.  We'd also need to check whether other
scripts can be addressed in a similar way.

Would it make sense to expand the remit of extended grapheme clusters in a
future version of this document (since I guess it may be a little late to
get such work done for this iteration)?

RI

============
Richard Ishida
Internationalization Lead
W3C (World Wide Web Consortium)
 
http://www.w3.org/International/
http://rishida.net/blog/
http://rishida.net/

 

> -----Original Message-----
> From: public-i18n-core-request@w3.org [mailto:public-i18n-core-
> request@w3.org] On Behalf Of Richard Ishida
> Sent: 07 March 2008 14:19
> To: public-i18n-core@w3.org
> Subject: RE: [UAX29] i18n comment 8: Conjunct clusters
> 
> 
> The added explanation about why conjunct clusters are not included is very
> useful.  I gather from the text that aksaras can be split after a virama
> if
> the conjunct glyphs do not interact visually (although that's not actually
> explicitly described).
> 
> I still feel that the current definition may stop short of being generally
> useful for some scripts.  For example, Khmer subjoined consonants are
> always
> treated as subscripts, as far as I am aware.  The grapheme cluster concept
> doesn't seem to be very useful for Khmer as it stands, but I think could
> be
> extended for this script as it was for Thai and Lao and become more
useful.
> I suspect this may also be the case for Myanmar.
> 
> RI
> 
> ============
> Richard Ishida
> Internationalization Lead
> W3C (World Wide Web Consortium)
> 
> http://www.w3.org/International/
> http://rishida.net/blog/
> http://rishida.net/
> 
> 
> 
> > -----Original Message-----
> > From: public-i18n-core-request@w3.org [mailto:public-i18n-core-
> > request@w3.org] On Behalf Of ishida@w3.org
> > Sent: 07 March 2008 11:34
> > To: public-i18n-core@w3.org
> > Subject: [UAX29] i18n comment 8: Conjunct clusters
> >
> >
> > Comment from the i18n review of:
> > http://www.unicode.org/reports/tr29/tr29-12.html
> >
> > Comment 8
> > At http://www.w3.org/International/reviews/0801-uax29/
> > Editorial/substantive: S
> > Tracked by: RI
> >
> > Location in reviewed document:
> > 3 [http://www.unicode.org/reports/tr29/tr29-
> > 12.html#Grapheme_Cluster_Boundaries]
> >
> > Comment:
> > We don't think extending default grapheme clusters to just incorporate
> > spacing marks goes far enough to actually providing better results for a
> > very large proportion of the world's population. We feel that the
> Unicode
> > TC should conduct further research on how to extend default grapheme
> > clusters so that they incorporate the majority of indic and south-east
> > asian syllables.
> >
> >
> > Example: It is very common to have a sequence such as
> > consonant+virama+consonant+vowel_sign, eg.
> >
> >
> > 0938: स DEVANAGARI LETTER SA
> >
> >  094D: ् DEVANAGARI SIGN VIRAMA
> >
> >  0925: थ DEVANAGARI LETTER THA
> >
> >  093F: ि DEVANAGARI VOWEL SIGN I
> >
> >
> > See this as it would be rendered
> >
[http://www.w3.org/International/reviews/0601-css3-selectors/sthiti.gif].
> >
> >
> > Without tailoring, the current rules would result in text wrapping the
> THA
> > to the next line, or attempting to highlight only part of the conjunct.
> > The basic unit for grapheme clusters for indic and south-east asian
> > scripts is the syllable, and just addressing spacing marks will still
> > leave you short of a useful solution.
> >
> >
> > We would like the Unicode TC to investigate the possibility of adding a
> > rule to say that a vowel killer character extends the grapheme cluster
> to
> > any immediately adjacent base character and all its combining
characters.
> >
> >
> > We feel that introducing a definition of default grapheme clusters that
> > addresses this issue will go a long way to helping ensure that
> > implementers provide applications that can handle South Asian and South-
> > East Asian scripts much better than now.
> >
> >
> > We feel that extending default grapheme clusters to include only spacing
> > marks may only complicate things further. We do not, however, feel that
> > the extension of grapheme clusters should be abandoned.
> >
> >
> 
Received on Friday, 7 March 2008 16:43:27 GMT

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