[XeTeX] Polytonic greek and XeLaTeX

[Mojca Miklavec]

On Dec 31, 2007 11:48 AM, Jonathan Kew wrote:
>
> So the explanation is that your text contained decomposed sequences,
> but Minion Pro doesn't support these. Indeed, looking into the font,
> I see that it lacks the combining marks from the Unicode 03xx block.
> So it will only work with accented Greek (or Latin, for that matter)
> if the data uses precomposed characters.

Hello,

I don't know anything about Greek, but can anyone explain me really
shortly how XeTeX handles de-composed characters?
I have always thought that  XeTeX does the composition automatically
(on a really low level), so that
 Ux63 (c) + Ux030C (caron) will result in Ux010D (ccaron)
no matter what the font designers have implemented for Ux030C (I
thought that the font doesn't even see the caron itself, but only sees
the final ccaron).

I have tested a few weird combinations, like:
    Ux3E (>) + Ux030C
and the caron gets placed over ">" properly (the definition of
"properly" might vary, but the main point is that it does get placed
:-). Now: who/what does that placement of caron over the greater-than
sign? XeTeX? The font (LM) itself?

If I write Ux63 (c) + Ux030C (caron): do I get the ccaron (in a badly
designed font with ccaron included, but with no smart features) or a
caron placed over c?

Thanks a lot,
    Mojca

PS: I did a few tests with one of the latest XeTeX and xdvipdfmx
versions (from SVN), Latin Modern and ConTeXt (though ConTeXt itself
should not behave differenty in that respect).