[luatex] macros to invoke lua in LaTeX

[Hans Hagen]

Joseph Wright wrote:
> Taco Hoekwater wrote:
>> Heiko Oberdiek wrote:
>>> In opposite to ConTeXt the core of LaTeX(2e) is frozen and
>>> it doesn't provide proper ways. :-(
>> You cannot reasonably use the bare latex2e core with luatex
>> anyway: if you don't need the extensions that luatex offers
>> then you are much better off running pdftex. I am starting to
>> wonder why this argument is ignored all the time ...
> 
> I think because at some point we all expect to see the default engine
> switch from pdfTeX to LuaTeX.  At that point, this becomes very important.

given our roadmap, this will not happen before 2012 (when we expect to 
have version 1.0) so there's quite some time for packages to adapt

anyhow, the engine landscape will be as follows:

- pdftex: stable, no unicode, but frozen apart from bugfixes: this will 
probably be used quite a while esp by those who want compatibility and 
speed (not everyone needs open type fonts and/or unicode)

- xetex: unicode, depending on libraries, relatively fast and easy to 
interface to fonts

- luatex: flexible unicode engine, no pre-cooked solutions, mainly a 
core engine, where macro packages have to do the work; downward 
compatible where possible (exceptions are in the dark corners of 
hyphenation and logging)

now, i've been sitting at quite some tex user meetings and whenever real 
new things came up there is always someone willing to bring up the "do 
we need it" or "we don't need it because it breaks old stuff" or "we 
have this standard input interface so forget about something else even 
if it's better" or "one could do it this or that way too" ...

the bottom line is ... there are quite some users (also think of 
journals) who probably will stick to pdftex just because it's not doing 
anything new that might result in incompatible output; that's also not 
the audience luatex is directly aiming at ... if eventually those users 
will use luatex (or xetex) it will be because they are not aware of the 
switch, just as many users are not aware that they had been running etex 
or later pdftex when they keyed in "tex" (after all many users are 
hapilly unaware of the difference between an engine and a macro package 
anyway)

> (Also just because one thing you want needs LuaTeX doesn't mean that
> everything else will have been re-written as well.)

believe me ... if you really want to use luatex you'll have to rewrite 
lots of code (ok, you can use it as pdftex with \directlua calls and not 
touch the nasty internals); eventually context (mkiv) will be 50% or 
more lua and currently it already spends over 50% of its time in lua, 
and as such is twice as slow as pdftex (which can be another argument to 
use multiple engines); and yes, context will support pdftex, xetex and 
luatex, simply because all are used by its users -)

Hans


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