On Mon, Sep 26, 2011 at 11:31:09AM +0200, Paul Menzel wrote:
> Am Montag, den 26.09.2011, 11:01 +0200 schrieb Wolfgang Schuster:
> > \definefontfeature[frac][frac=yes,script=latn]
> > 
> > \setupbodyfont[cambria]
> 
> Is there a font in Standalone which can be used to demonstrate the
> behavior?

XITS, but you will get output as you describe below, which I know is
buggy since the font lacks generalised frac feature.

> > \starttext
> > 1/40 {\setff{frac}1/40} \m{\frac{1}{40}}
> 
> With `{\setff{frac}1/40}` the output is like ¼0. Using `{40}` also does
> not help.

Looks like frac here is a simple ligature of few predefined fractions.

Regards,
 Khaled

-- 
 Khaled Hosny
 Egyptian
 Arab