[XeTeX] Status of babel and polyglossia in xelatex

[Ulrike Fischer]

Am Wed, 9 Dec 2009 18:29:25 +0800 schrieb Vladimir Lomov:

> I play with xelatex for some time but don't understand status of
> polyglossia and babel in xelatex.

> As I understand, polyglossia is a replacement for babel (babel in latex,
> polyglossia in xelatex) so I should not use babel with xelatex.

Well you can use babel with xelatex and in certain cases it is more
powerful, e.g. the french adaption of babel has much more typograpic
settings than the one from polyglossia. 

You should in general _not_ use babel if you use a language which
needs another script (like russian) as it will switch fontencodings
and probably clash with fontspec. 

> 
> If this is correct then why when I run xelatex on this minimal document
> I see:
> <output>
> This is XeTeX, Version 3.1415926-2.2-0.9995.2 (TeX Live 2009)
> entering extended mode
> (./test2.tex
> LaTeX2e <2009/09/24>
> Babel <v3.8l> and hyphenation patterns for english

> This is rather strange for me: if xelatex don't use babel why it has
> babel banner?

A part of the code of babel (some kernel commands needed to load
language patterns) are in hyphen.cfg and included in the format.
That's not a problem, polyglossia knows it, it needs such code too
and simply reuse the one from babel. (At first polyglossia had its
own hyphen.cfg, which meant that you had to regenerate the formats
if you wanted to switch between babel and polyglossia. Happily this
is no longer needed.)

-- 
Ulrike Fischer