# [XeTeX] Let's discuss \mathchar again

Bruno Voisin bvoisin at mac.com
Mon Dec 12 10:37:40 CET 2005

```Le 12 déc. 05 à 04:02, Will Robertson a écrit :

> However, you've said in the past that TeX uses special TFM metrics
> for maths typesetting that aren't provided for in unicode fonts; is
> there more to this story than the extra fontdimens? Because if so,
> we are indeed unable to proceed.
>
> [...]
>
> Or is it all a moot point because you need voodoo in the maths font
> (that OpenType can't provide) to tell TeX what to do?

I'm just wondering whether the STIX fonts, when finally released,
would answer these questions partly (being Unicode math fonts if I
understood correctly). But yes, you'd basically have to rewrite plain
TeX (and probably LaTeX as well), whose treatment of maths is very
deeply tied to the idiosyncratic encodings of the Computer modern 7-
bit math fonts. Or did the Omega people dealt with this in some