[XeTeX] does language switching works properly?

[Antonis Tsolomitis]

In Greek (and Russian) the guillemots are different than the default. So
the NewCM fonts
include a lookup cv04 for the Greek and cv03 for the Russian to switch
to the proper glyphs.

I thought that if cv04 has metadata

grek(dflt)

and if I switch to Greek using the polyglossia command
\textlang{greek}{\newcmgreekguillemots «»}

where

\newfontfamily\newcmgreekguillemots[CharacterVariant=4]{NewCM10-Book.otf}

then the substitution will work. But it does not.

If I add to metadata

latn{dflt}

then it works. But is this proper? Shouldn't it work only with grek{dlft} ?

It is either my understanding wrong or polyglossia does not do the
proper switching or xetex
does not pickup the change of language properly.

In my sources I have added latn{dflt} for both Greek and Russian to make
the fonts work.
So if a test is needed I have to send a custom font.

Thanks,

Antonis.












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