# [luatex] a question about the names \Umathcharnumdef etc

jfbu jfbu at free.fr
Fri Oct 16 11:41:34 CEST 2015

Le 16 oct. 2015 à 10:45, Joseph Wright <joseph.wright at morningstar2.co.uk> a écrit :

> On 16/10/2015 09:35, jfbu wrote:
>>
>> Le 16 oct. 2015 à 09:47, Ulrike Fischer <luatex at nililand.de> a écrit :
>>
>>> Am Thu, 15 Oct 2015 18:18:58 +0100 schrieb David Carlisle:
>>>
>>>>> or perhaps \Umathcharnumdef was always ok ?
>>>>
>>>> yes, it was, the Umath... commands were always available with their
>>>> basic luatex names and also prefixed luatex.
>>>
>>> That's not true. In a texlive 2012
>>>
>>> \documentclass{article}
>>>
>>> \begin{document}
>>> \show\Umathcharnumdef
>>> \show\luatexUmathcharnumdef
>>> \end{document}
>>>
>>> gives
>>>
>>>> \Umathcharnumdef=undefined.
>>> l.36 \show\Umathcharnumdef
>>>
>>> ?
>>>> \luatexUmathcharnumdef=\Umathcharnumdef.
>>> l.37 \show\luatexUmathcharnumdef
>>
>> The file
>> /usr/local/texlive/2012/texmf-dist/tex/latex/latexconfig/lualatexiniconfig.tex
>> says that
>>>  % etex and pdftex primitives are enabled without prefixing
>>>  % as well as extented Unicode math primitives (see below)
>>>
>>
>> but as your test file shows this was not the case for \Umathcharnumdef
>> (and also \Umathcodenum which I tested).
>
> In older versions of LuaTeX, the \U... primitives were part of the
> "luatex" list so were enabled with the \luatex... prefix. Those
> primitives now live in a dedicated "umath" list so cn be enabled
> separately from the other LuaTeX-specific ones.

The "umath" list in mentioned in

/usr/local/texlive/2012/texmf-dist/tex/latex/latexconfig/lualatexiniconfig.tex

mentioned above, which has a tag
$Id: lualatexiniconfig.tex 28991 2013-01-30 20:46:39Z hosny$

and the comment seemed to say the Unicode math primitives
had been enabled without "luatex" prefix. But Ulrike's test showed
this was not accurate. But I don't want to invite people
waste their time debugging a TeXlive 2012 issue ...

>
>> I recall now that mathastext prior to TeXLive 2013 did not use
>> \luatexUmathcharnumdef because the right side of the assignment would have
>> been \luatexUmathcodenum\-\relax, but \luatexUmathcodenum back then
>> did not always return a Unicode mathcode.
>
> This is the issue with supporting older versions of a developing engine!
> I'd suggest you strongly consider saying that only newer releases are
> supported. (The LaTeX team are considering much the same for
> expl3/LuaTeX support.)
>
> Joseph

Well, my package does tell people they need LuaLaTeX from TL2013 or later,
and the latest modification impacting the package did
not come from an evolution of the engine, but from LaTeX 2015/10/01.

In principle, I understand your point, but LuaTeX having been
part of the TeX landscape for many years now, it is hard to view
it as a constantly developing engine needing the package authors
to support only the latest version and telling the users to adapt...

... as I personally was stuck for many years with a laptop on which I
would not install TeXLive 2011 or later, and although
owner of a Mac I could not use xetex (for reasons I have forgotten)
I am aware that software requirements may induce hardware incompatibilities,
and actually a lot of the computer business makes it money from that.

If the package was truly exploiting LuaTeX, the matter would be
a bit otherwise, but here it is just a question of having a minimum
of compatibility with Unicode,

best
Jean-François

`