bug#64420: string-width of … is 2 in CJK environments

[Eli Zaretskii]

> From: SUNG TAE KIM <itaemu@gmail.com>
> Date: Fri, 14 Jul 2023 18:21:42 +0900
> Cc: 64420@debbugs.gnu.org
> 
> What I meant by default was default in the CJK language environment and the 
> default width of the
> ambiguous characters in CJK environment should be narrow. Current emacs 
> changes the width of
> ambiguous characters to wide if the user activates the CJK environment. The 
> unicode standard
> recommendation is set the width narrow at unclear circumstances but emacs 
> changes the width to
> wide even if it can't know what font is currently used. For that reason, I 
> don't think such behavior is
> aligned well with the unicode standard.

We don't blindly follow the Unicode Standard.  We seriously consider
its recommendations, and then do whatever we think is best for our
users.

> Furthermore, The majority of the default width of those
> characters in the CJK environment is narrow on contemporary implementation of 
> the terminals from
> my limited experience. However, Considering the emacs package ecosystem, 
> current emacs
> behavior is ok as long as there's an easy option for changing such values.

It is not yet clear to me whether handling these characters as narrow
by default in CJK language-environments is TRT.  But adding an option
to do so is a first step in that direction, if indeed this is the
right direction: we can in the future make this optional behavior be
the default, if we arrive at the conclusion that most users configure
their fonts and their terminal emulators such that these characters
have the narrow width.