[XeTeX] warning: XeTeX & broken typescripts (please wait with upgrading)

[Mojca Miklavec]

Hello,

While waiting for the train in Köln (just back from one of the best
ConTeXt meetings ever ;), I decided to post this warning/explanation
to the mailing list (before Hans gets back and blocks my account ;)

For those who rely on (complex) XeTeX typescripts, please don't
upgrade ConTeXt as long as you have a working version (if not, you can
download and extract an older zip from
https://foundry.supelec.fr/frs/?group_id=14).

Hans is currently working on a high-level user interface for
typescripts in luatex, and the old behaviour has been slightly broken,
mostly due to the fact that if one wants to support fonts that are not
installed, the bracket notation has to be used, which doesn't fit well
into the model (one would need to specify fonts in constructs such as
[{{'[fontname]'}}]). Without rewriting some basic routins, the font
definition would look really strange that way.

Currently the format builds OK (it was completely broken for some
time, but now you can at least work with it again), you can still
select fonts with constructs like
    \font\a='TestFont/BI:mapping=tex-text' \a
and you can also define synonyms like (I hope that I got it right this time)
    \definefontsynonym[MyFont][name:RealFontName][encoding=uc]
    % encoding will go (has gone?) away
but typescripts don't really work the way that worked once.

XeTeX typescripts have been relatively primitive so far: the syntax like
    \definefontsynonym  [DidotItalic]
['Didot/I:mapping=tex-text:+dliga'] [encoding=uc]
is not the best possible ansd will most probably not be supported any
more. Instead, one would probably write something similar to
     \definefontsynonym [DidotItalic] [name:Didot] [features=dliga]
     % mapping=tex-text might be default
but that's not the final word about it yet.

Sadly Adam Lindsay (who created the whole machinery) doesn't have much
time to work with ConTeXt, and I'm not really a TeXacker (if anyone
else is willing to help, any help would be more than wellcome).

I don't want to force too much the fix (it's better to have it
implemented properly and to wait some more), although I hope that it
won't take too much time to have it finished. I was silently hoping
that Hans will finish the luatex OpenType support before the whole
machinery could be backported to XeTeX, but sadly it was
(unintentionally) broken before a good replacement could be provided.
I would like to ask the ConTeXt-XeTeX users for understanding.

I cross-posted that message, but in case that you would need to reply
for some reason, please do so on the ConTeXt mailing list, not on the
XeTeX one, since XeTeX itself has really nothing to do with the
subject (apart from the slightly unfortunate syntax for selecting
uninstalled OpenType font).

Mojca