Why doesn't Ideographic (ID) in UAX#14 have half-width katakana?

suzuki toshiya mpsuzuki at hiroshima-u.ac.jp
Mon Apr 27 22:14:54 CDT 2015


At present, I have no objection to add halfwidth katakana
to ideographic-class in UAX#14, but I'm unfamiliar with the
(negative) impact caused by the lack of halfwidth katakana
in it. Could you tell me if you know anything?

I guess, the inclusion or exclusion in other classes, like,
AI, AL, CJ, JL, JV, JT, SA might be quite important to realize
the appropriate line breaking, but the inclusion or exclusion
in ID-class does not seem to be important. If the inclusion
in ID-class is important, more characters (e.g. Bopomofo)
should be considered for full coverage. How do you think of?


Makoto Kato wrote:
> Hi.
> http://www.unicode.org/reports/tr14/proposed.html#ID defines Ideographic
> (ID).  Although full-width katakana is included in ID, half-width
> katakana (U+FF66 and U+FF71-U+FF9D) isn't.  Why?
> Also, Conditional Japanese Starter (CJ,
> http://www.unicode.org/reports/tr14/proposed.html#CJ) considers
> half-width variants such as half-width katakana letter small a.
> -- Makoto

More information about the Unicode mailing list