# [NTG-context] using lua fonts

Hans Hagen j.hagen at xs4all.nl
Wed May 9 13:05:34 CEST 2018

```On 5/9/2018 12:40 PM, Ulrike Fischer wrote:
> Am Wed, 9 May 2018 09:56:50 +0200 schrieb Hans Hagen:
>
>> watch how i replaced the * by : because only context has the * syntax
>
> Thank you very much for this explanation. I was wondering about the
> same thing and replacing this made the code going.
>
> Perhaps a general remark: I and certainly Henry too are quite aware
> that some of the code is context specific. But it is often quite
> difficult to see the boundaries -- which part of the examples are
> generic and which rely on context (and on how much in context). It
> is also not easy to decide which (lua) functions are "public" and
> won't break at the next update of the font handler.

normally function that are part of the generic loader code are publis
(one can argue about the low level helpers as these are only loaded for
the code to work i.e. i have no clue how useful these are outside
context) .. that code doesn't change that much nowadays (just assume
that i also use it in modules sometimes and i don't want to change that
too often)

then there is the wrapper code (that hooks into callbacks) which is also
mostly stable (unless we add something fundamental)

for instance, the effects feature has a sort of sub syntax that suits
context feature definitions, so for latex you probably need to map onto
that somehow ... i happily leave that to others to figure out as i don't
want to impose something (the same is true for variable fonts)

the big font manual is a context one so there can be examples that
assume the context user interface and there is not much we can do about
that (and i don't know much about latex apart from what i occasionally
see at some tex meeting) ... wrrt the font loader: the luatex-plain
version is sort of the generic reference ... anything written on top of
that is specific for a macro package

another difference is the font database ... i'm pretty sure that the
context one is quite generic but latex folks wanted their own so ...

> Henri: As you are interested in these things too, do you think it
> would be a good idea to setup a github repository where we collect
> such (plain and latex and context) examples?

anyway, if something doesn't work at some point we can always see why
and provide a compatibility hack in luatex-fonts-hacks or so

Hans

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