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Date: Thu, 21 May 2009 04:40:54 +0900
Message-ID: <3f0ad08d0905201240g1ea7dd8at8843e5fabb17fcbc@mail.gmail.com>
Subject: Re: [Fwd: [1.7] wcwidth failing configure tests]
From: IWAMURO Motonori <deenheart@gmail.com>
To: newlib@sourceware.org, cygwin@cygwin.com
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2009/5/21 Thomas Wolff <towo@towo.net>:
>> > Therefore, I propose to use *_cjk() when the language part of LC_CTYPE
>> > is 'ja', 'ko', 'vi' or 'zh'.
> The problem with this is
> 1. As you say, there is no standard.

But,
- I think that my proposal doesn't violate any specification.
- I heard that there is an existing implementation that behave like my
proposal. (Sorry, I didn't hear the system name.)

> 2. If you wish to handle character widths compliant with the terminal
> =A0 your application is running in, there is no guarantee that your
> =A0 assumption of CJK width (or the actual locale setting if that model
> =A0 would be implemented) does indeed reflect the terminal's width proper=
ties.

Yes, I understand it, too. My proposal is completely workaround.
But it is the best solution because we have no specification/standard
for my wish.

> 3. In mintty, you can dynamically change width properties by selecting
> =A0 different fonts; mintty changes CJK width behaviour according to cert=
ain
> =A0 font properties. "static" configuration in your shell using a locale
> =A0 variable would not reflect this change

It is no problem because we -- most Japanese language users -- need
not change the settings of mintty and locale after first setup.
We set LANG=3Dja_JP.UTF-8 and select a Japanese font for mintty.

> =A0 I see two ways to handle this:
> =A0 a) Ask Andy (author of mintty) to not do this switching;

It is not necessary bacause the mechanism is based on my another
poroposal. ("deenheart" is my handle on google code.)

> other terminals don't switch either.

If we use other terminals, we need switch CJK width option manually.
(xterm, mlterm, putty, ...)

> =A0 b) Determine the actual CJK width behaviour dynamically. That's what
> =A0 =A0 =A0mined does (in addition to other width property detection in g=
eneral).

It is the best solution. I think that we need specify the following:
- the escape sequence about language context for terminal emulater.
-- setting language context
-- getting language context
-- getting capability of language context
   (context is fixed, static or dynamic / acceptable languages)
- new multilingualized string/terminal API for terminal based applications.

And, we need rewrite too many applications by new API.

> I'm not happy with the idea of a cygwin-specific solution (or workaround).

I think that it is not cygwin-specific solution.
--=20
IWAMURO Motnori <http://vmi.jp/>

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