[XeTeX] Fwd: Re: Case changing for Greek

[Bruno Le Floch]

It appears that the Unicode Core Specification (version 7.0.0) defines
in Table 3-14 what a Final Sigma is.  A sigma is final if the previous
character is cased and the next is not, ignoring case-ignorable
characters completely.  To know which characters are
cased/case-ignorable, see the properties Cased and Case_Ignorable
listed in the file DerivedCoreProperties.txt.

See p.82 (labelled 153) of
http://www.unicode.org/versions/Unicode7.0.0/ch03.pdf which says:

> C is preceded by a sequence consisting of a cased letter
> and then zero or more case-ignorable characters,
> and C is not followed by a sequence consisting of zero or
> more case-ignorable characters and then a cased letter.
>
> Before C    \p{cased} (\p{case-ignorable})*
> After C    ! ( (\p{case-ignorable})* \p{cased} )

Regards,
Bruno