[XeTeX] On cross-language font selection

[Jjgod Jiang]

Hi,

在 07-2-16，Yin Dian<yindian at gmail.com> 写道：
> Hi jjgod,
>
>    I came up with an inspiration yesterday night on the macro implementation
> of font selection and space skipping. It is based on the thought of explicit
> switch via the active tilde. After an hour's hack I've finished the
> primitive part. Further development requires a judge for math mode and
> parameterized commands, so the change of behavior of backslash and braces is
> needed.
>
>   Following is a test case encoded in UTF-8. Compiled successfully on my
> XeTeX 2.2-0.996.

Are you sure it's working, because I got the following error in the
same version:

This is XeTeXk, Version 3.141592-2.2-0.996 (Web2C 7.5.6)
 %&-line parsing enabled.
entering extended mode
(./yin.tex
! Undefined control sequence.
<recently read> \xchinese@

<to be read again>
                   i
\xchinese at iterate ...?  \expandafter \xchinese@ i
                                                  terate at next   \fi
l.85

- jjgod.