[XeTeX] Avoiding hyphenation before a combining diacritical mark

[Aleksandar Zec]

2010/11/15  <enrico.gregorio at univr.it>:
> I don't get the hyphen if I put
>
> \XeTeXinputnormalization=1
>
> in the preamble and write the offending word as
>
> βαίνο
>
> i.e., inserting a COMBINING ACUTE TONE MARK (U+0341) after the iota
> (the software used for this message probably does the combination by
> itself). The same if I use COMBINING ACUTE ACCENT (U+0301).
> But no, not with \char.

No, \XeTeXinputnormalization is not what I am looking for. In my
example, Greek language, alpha and combining acute are there just for
the sake of simplicity. In the real material, I have more complex
pairs that certainly do not have precomposed variants.

To put it the other way, I need a simple way to tell xetex not to
hyphenate before such and such characters, in this particular case,
before U+0301, U+0302, U+0303, etc. (Whatever harm it does to the
actual language of the text in question.)

Thanks,
Alex