[XeTeX] The future of XeTeX

[Paul Isambert]

Ulrike Fischer <news3 at nililand.de> a écrit:
> 
> Am Tue, 7 Aug 2012 08:51:41 +0200 schrieb Paul Isambert:
> 
>  
> >>>> But there are also political issues: LuaTeX is developed by a
> >>>> team focusing on ConTeXt. LaTeX users will always be neglected,
> >>>> at least that is the feeling I have (Taco is very kind and
> >>>> helpful but he is paid for a specific task, and LaTeX is not
> >>>> part of it).
>   
> >>> I thought somebody would answer to that but nobody did, so (sorry to add
> >>> to this already too long thread, all the more as I won't even mention
> >>> XeTeX):
>   
> >>> Two members of the ``core'' LuaTeX team (Taco and Hans) are indeed two
> >>> main ConTeXt developers (and even original author, in Hans's case), but
> >>> I don't think you can say LuaTeX development focuses on ConTeXt (plus
> >>> Hartmut, the third member, is a LaTeX user, as far as I know). I'd
> >>> rather say that at most LuaTeX development may be driven by the needs
> >>> of ConTeXt developers, but that doesn't mean it benefits only to ConTeXt;
> >>> also, given ConTeXt's high standards, I think it's only for the best.
> >>> And the specific task Taco is paid for does not include LaTeX, but it
> >>> does not include ConTeXt either.
> >> 
> >> Well if you look only at the actual binary then yes your are right:
> >> it is not focused on context. But the handling of fonts is a core
> >> feature of a typesetting system. No user of a typesetting system
> >> would consider it to be complete if it can't handle standard fonts.
> >> So even if in luatex the font loader (including all the code needed
> >> to generate caches) is in external lua-files, it should nevertheless
> >> be considered to be part of "the luatex binary". It shouldn't
> >> delegate font handling to the formats.  
> 
> > I understand you're concerned about future font support in LuaTeX, but
> > technically the engine is little more than an extendable PDFTeX. 
> 
> I know this. But you are again looking only at the binary itself, at
> the "engine" in the narrow sense. I'm looking at the "typesetting
> project luatex". 
> 
> > Fonts follow that philosophy: TFM (with mapping to T1) fonts are
> > supported as in PDFTeX, other formats must be loaded and
> > processed by hand. Whether it's a good idea or not in that case I
> > don't know, but it is definitely consistent. (Actually I do think
> > it's a good idea, but I accept my opinion might be marginal.)
> 
> I personally don't care much *how* e.g. open type fonts are handled.
> The "typesetting engine" can use an external library, lua-files, or
> some library included in the binary. I care only *if* the core
> engine itself, the part advertised on the webpage, can handle the
> fonts like a bare xetex can handle them. 
> 
> Sorry, but can you imagine that a typesetting engine can thrive
> which must say on its webpage "I'm a wonderful tex engine based on
> unicode but if you want to use open type fonts you will have to
> write or adapt a lot of complicated code first".?

Honestly, yes :)
That's what TeX is to me anyway: a wonderful system that requires a lot
of hard work.

On http://www.luatex.org/roadmap.html, you can read:

    There are two solutions for handling fonts: using the internal
    functions that do what TeX has always done, or write a Lua function
    that does a different job. As there are multiple solutions possible
    and as we expect macro packages to have their own ways of dealing
    with fonts, there is not one solution for dealing with fonts anyway.
    Also, TeXies have always wanted full control over matters, and this
    is provided by the Lua solution.

In a few years, TeX users will have sprouted new wizards that'll deal
with fonts like the current wizards play with \output and \expandafter.

> > Now, as I've already said, Hans has written a format-independent font
> > loader; somebody is only required to make the necessary adjustments to
> > (La)TeX, as Khaled did until recently. 
> 
> At first it should not be necessary "to make adjustments". A
> format-independant font loader should work like the extended
> \font-command of xetex "out-of-the box".

To me the XeTeX syntax is rather the frosting on the cake; the important
point is that a font be loaded and processed.

>                                          At second as some people
> complained here in the discussion the font loader doesn't work e.g.
> with indic fonts. At third it is undocumentated and unmaintained.

For that I'd say give it time, especially the ``unmaintained'' part:
Khaled has only recently announced that he stopped maintaining
luaotfload.

> > My main point was not whether LuaTeX was well-designed, but
> > whether (La)TeX users could be said to be neglected, which I
> > still think isn't the case.
> 
> LaTeX (and the other formats) were neglected because the development
> of a vital part of the luatex-project - the open type font loader -
> has not be developed in a format independant way. 

It has been, to some extent; and it's only transitional.

A 100% format-independent fontloader isn't really possible, unless you
freeze it completely. If you want to add your own bells and whistles,
which is what LuaTeX is about as far as I'm concerned, you have to
adapt it, or better, in the case of formats, write it from scratch.

Best,
Paul