Fwd: [css3-text] Thai line breaking rules

-------- Original Message --------
Subject:  [css3-text] Thai line breaking rules
Resent-Date:  Mon, 07 Feb 2011 03:47:45 +0000
Resent-From:  www-style@w3.org
Date:  Sun, 6 Feb 2011 22:47:21 -0500
From:  Koji Ishii <kojiishi@gluesoft.co.jp>
To:  www-style@w3.org <www-style@w3.org>



I had a meeting with ILCAA, Research Institute for Languages and Cultures of Asia and Africa[1] in Tokyo. Minegishi-san at ILCAA presented his idea for the issue currently mentioned in the CSS3 Text spec[2]:

>  Additionally, some guidance should be provided on how to break
>  or not break Southeast Asian in the absence of a dictionary.

Here's his draft of the simple line breaking rules in the absence of a dictionary for Thai scripts. Any corrections, and/or opinions whether to include this in the spec or not would be appreciated.

Thai character groups are based on TIS 620-2553 as written in Unicode spec[3].
   Consonants: U+0E01-0E2E

Line breaks are prohibited between:
* Any and U+0E2F
*<Consonants>  and [U+0E30-0E3A]
* [U+0E31, U+0E3A, U+0E40-0E44] and<Consonants>
* U+0E3F THAI Currency Symbol BAHT and digits
* [U+0E24, U+0E26] and U+0E45
* [U+0E50-0E59] and [U+0E50-0E59]
* Any and U+0E5A

Following rules are also presented, but they are Unicode Lm or Mn category and therefore I suspect that UAX#29 Unicode Text Segmentation should cover these rules.
* Any and U+0E46
*<Consonants>  and [U+0E47]
* (<Consonants>  or [U+0E34-0E39]) and [U+0E48-0E4B]
* (<Consonants>  or [U+0E34-0E39]) and U+0E4C
*<Consonants>  and [U+0E4D-0E4E]

[1] http://www.aa.tufs.ac.jp/en
[2] http://dev.w3.org/csswg/css3-text/#line-breaking
[3] http://unicode.org/charts/PDF/U0E00.pdf
[4] http://unicode.org/reports/tr29/

Regards,
Koji