Re: Prefer luatex for documentation

[Luca Fascione]

On Mon, Nov 21, 2022 at 2:23 PM Werner LEMBERG <wl@gnu.org> wrote:

>
> > Sorry, luatex is like 10yrs old, what's the need for xetex again?
>
> Some issues that potentially speak against using luatex:
>
> * LuaTeX's OpenType support is still in flux and sometimes buggy.  The
>   future is probably luatex-hb, using the 'HarfBuzz' library for
>   OpenType font handling.
>

Yes, that seems to be their opinion as well.



> * The main target of LuaTeX is not LaTeX but ConTeXt, which means that
>   some features (speak: extensions) are probably not as much tested.
>

As one data point, the stuff I build myself is substantially more complex
than the luatex documentation
(lots of maths), minus of course the truckloads of inlined minipdf's the
docs have because of including the music
(which I believe can be done more tightly in luatex, like one would use
pigmentize, but we digress).
Although they do target ConTeXt, I can't say that LaTeX runs poorly on
luatex, actually it seems to me it runs just fine.


> * AFAIK, `luatex` is *much* slower than `pdftex`.
>

I'd say that for a 80-100page document it's maybe somewhere between 50% and
twice as slow.
Still it's a several seconds build that becomes more several seconds.
I'm not sure it crosses important workflow thresholds [1], it certainly
didn't in my own use.

[1] http://enderton.org/eric/pub/workflow.pdf

> > Maybe I could justify pdftex (I really don't quite see it, but
> > maybe) but xetex seems just arbitrary... Or do you mean for a
> > transition period?
>
> We changed to XeTeX because pdfTeX produces invalid PDF outlines if
> non-ASCII characters are involved.  This is not a problem with pdfTeX
> itself but due to lack of support in `texinfo.tex`.  At that time of
> the switch, LuaTeX support wasn't ready – there was a `luatex` bug
> that stalled further work for two months or so (until someone
> suggested a workaround, see MR !1740).
>

Ok but then are you saying pdfTeX is not usable today, and it's either
XeTeX or LuaTeX today?


> > What's the oldest system that this Lilypond would be used on?
> > What's the youngest texlive that will run on that system? That's
> > your tex distro of reference.
>
> TeXLive runs on virtually *all* systems, even old ones based on the
> i386 chips.  This means there is no useful answer, AFAICS.
>

Au contraire: it means you can ask anybody that builds our docs to upgrade
their tex distro to a new one,
and they'll have a working LuaTeX "no matter what system they use othrwise".
Which seems to me it's a very useful answer (it removes one constraint I
guess).


-- 
Luca Fascione