[XeTeX] disabling xetex's default classes

[Michiel Kamermans]

Jonathan Kew wrote:
> The code that sets these up is in unicode-letters.tex, which is read 
> during the creation of the default xetex and xelatex formats. You can 
> easily write a loop that simply resets the classes of all the 
> characters to 0, and override the \XeTeXinterchartoks commands in that 
> file with null versions if you wish.
>
> (That code really should be updated to use \newXeTeXintercharclass and 
> symbolic names, anyway....)
Ahh, that's going to be asking a bit too much from users I guess... I'm 
updating my old fontwrap package, and making a new package 
unicodecharclass in the process which assigns each unicode block its own 
class number, counting down from class 240 (there's 167 blocks in 
unicode at the moment, so that leaves 70 classes on the left, and a 
handful on the right), but it might be that classes 0 through 3 could 
interfere. By default I have the package now set up blank transition 
rules, so things should be just fine, but if there had been a way to 
'empty' classes 0 through 3 without editing files, that would have made 
things safer =)

I'm not sure how this will behave in conjunction with polyglossia, since 
that uses a decent number of classes too, but it seems like the number 
of languages that supports is much lower than the 70 classes left 
untouched by this package.

Has there been a 'ruling' on the \newXeTeXintercharclass concept? I read 
up on the posts for it from last May, but it looked like there'd not 
been any concrete decisions on what to do with it, just that it was a 
pretty good idea (which it is =).

- Mike