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Date: Fri, 15 May 2009 00:58:38 +0900
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Subject: Re: [Fwd: [1.7] wcwidth failing configure tests]
From: IWAMURO Motonori <deenheart AT gmail DOT com>
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2009/5/13 Corinna Vinschen <vinschen AT redhat DOT com>:
>> http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
>
> This looks nice.

Do you import Markus Kuhn's wcwidth implementation?

>> Trouble is, there's the thorny issue of the "CJK Ambiguous Width"
>> category of characters, which consists of things like Greek and
>> Cyrillic letters as well as line drawing symbols. Those have a width
>> of 1 in Western use, yet with CJK fonts they have a width of 2. That's
>> why Markus Kuhn's code includes the mk_wcswidth_cjk() variant.
>
> We should use the standard variation alone, imho.

I don't think so.

1) It is very very inconvenient for me :-)
(Now, I apply the local patch of CJK width support to cygwin1.dll in
my environment.)

2) Unicode Standard Annex #11
http://www.unicode.org/unicode/reports/tr11/ recommends:
> 5 Recommendations
(snip)
> When processing or displaying data
(snip)
> Ambiguous characters behave like wide or narrow characters depending
> on the context (language tag, script identification, associated
> font, source of data, or explicit markup; all can provide the
> context). If the context cannot be established reliably, they should
> be treated as narrow characters by default.

The recommendation is independent of legacy encoding.

I think that a new locale category that specifies the "context" is necessary.
Because the "context" influences only the display or text layout.

However, there is no such standard now.

Therefore, I propose to use *_cjk() when the language part of LC_CTYPE
is 'ja', 'ko', 'vi' or 'zh'.
-- 
IWAMURO Motnori <http://vmi.jp/>

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