[XeTeX] \meaning on a \csname \let to a character

[Khaled Hosny]

On Tue, Jan 08, 2013 at 11:26:51PM +0000, David Carlisle wrote:
> In a similar thread ,\meaning or \show  on a mathchardef'ed character
> such as \sumop
> 
> in xetex gives
> 
> \sumop=\XeTeXmathchar"202211
> 
> in luatex
> 
> \sumop=\Umathchar"1"00"002211.
> 
> the luatex version looks distinctly odd but is legal input.
> 
> With the xetex version if you input it
> 
> ! Bad math class (2105873).
> <to be read again>
>                    $
> l.15 $\XeTeXmathchar"202211$
> 
> It needs to be input as \XeTeXmathcharnum (or to use the 3 number
> version as in luatex)
> 
> This means that if you write the \meaning out to a file and later read
> it back  (or you use \scantokens or similar processing) you have to
> fix up the input which isn't impossibly difficult but unexpected (and
> makes it harder to work with both engines)
> 
> Perhaps this is changed in the development version already? If not,
> any chance it could be?

It does now. Moreever, \meaning\mitalpha now gives

\mitalpha=the letter ��

(LuaTeX gives "the character", but that is because the luatex formats
does not give non-BMP math alphabets letter catcodes).

Regards,
Khaled