[XeTeX] gloss-russian.ldf bug

[Ulrike Fischer]

Am Wed, 26 May 2010 22:11:24 +0400 schrieb Vadim Radionov:

> Thank you, Ulrike and Vladimir,
> 
> Setting \russianfont to nothing solves the problem.

I don't know if this is the best solution. I don't know much about
russian and the fonts involved. It could be that e.g. using
\addfontfeature is better, or setting a fontfamily or ....

 
> But is there any reason to pass this assignment to the user?

The source of the problem is that when switching to another
language/script fonts must sometimes change, sometimes only by
adding a script option to the current fonts if the fonts contain
glyphs of both scripts, sometimes by using a completly different
font setup -- where the new font setup sometimes has features like
\itshape, \ttfamily or bold and sometimes not. And the changes don't
depend only on the new language: The change from russian to german
is different to the change from chinese to german. XeTeX/fontspec
has the additional problem that the information given by the
encoding of a font is no longer present. (In standard LaTeX T1, LGR,
T2A etc represent to some extend scripts.)

I don't think that it is really possible to write code that get all
this transistions right without some help from the user who at least
knows the languages and the fonts used by the document. 

But I also think that simple font switching commands like the defaut
definition of \russianfont are not enough. Languages should store
their script in a variable and font switching should be done only if
the script actually changes. It should also be possible to tell
xelatex/polyglossia that a font setup can be used with more than on
script.



-- 
Ulrike Fischer