Philip Taylor (RHBNC) wrote:

> >> So, I think, that the correct way to solve this problem is to
> >> set the values of \lccode, \uccode, \sfcode and \mathcode,
> >> in a macros which switches to a language (\selectlanguage
> >> in Babel).
> >> Are there some ready means to preserve the `language environment'
> >> before switching to another language and to restore it after
> >> changing back (or to some third language)?
> >> Is it a normal practice to `tune' \lccode, \uccode, \sfcode
> >> and \mathcode values in a language-switching mechanism?
> One idea under consideration for e-TeX V2 is the option to save and
> restore an entire set of register values (e.g. the current set of
> lccodes, etc); this may prove useful in solutions to this question.

Yes, that would be a good option. But I think that \uppercase and \lowercase
will not work correctly even with this option if the argument of \uppercase
(or \lowercase) is a multilingual text, and languages have different
(inconsistent) \uccode and \lccode values. To correct his, one needs to
redefine TeX's primitives as I wrote in my previous letter.

BTW, it is interesting to know, what is the current status of e-TeX?
Is it widely used? Is there a support for new e-TeX's primitives available
in LaTeX?

With best regards,