[lltx] adapting unicode-letters to luatex

[Manuel Pégourié-Gonnard]

Hi,

I'm following up on the recent discussion on the Luatex mailing list concerning
hyphenation in Greek not working properly with Lualatex, due to the various
\lccode's not being set properly.

I can see that in Xetex-based Plain and Latex formats, the file
unicode-letters.tex is \input-ed and takes care of such things. This file is
generated by the Perl script unicode-char-prep.pl shipped with the Xetex sources
and taking Unicode data files as its inputs (available from
<http://unicode.org/Public/UNIDATA/>).

As is, unicode-letters.tex cannot be usefully \input-ed by LuaTeX, since it
makes use of primitives (\XeTeXmathcode) and even concepts (intercharclass and
interchartoks) specific to Xetex. However, a big part of it (uccodes, lccodes,
sfcodes, catcodes, maybe mathcodes to by just adapting the primitive name) could
be shared with Luatex.

I see at least to possible ways to handle this:
1. Adapt unicode-char-prep.pl so that the generated file can be \input'ed by
both Xetex and Luatex.
2. Make a Luatex-specific version.

I've got no strong opinion on 1 vs 2, but is seems to me that it's probably
easier to have a separate Luatex version, to avoid bothering you, Jonathan,
every time something needs to be changed for LuaTeX.

What do you guys think?

Either way, I'm interested in working on it (in case the only problem is to find
someone to do it).

Manuel.