[luatex] macros to invoke lua in LaTeX

[Karl Berry]

    Anyway, if the LaTeX team is serious about preventing backwards 
    compatibility problems, then we should do things like rename LuaTeX 
    primitives into a "namespace" 

I agree.  It will certainly cause a lot of confusion in terms of
documentation, etc., but I don't see a better alternative.

And I think the likely-clashing current primitives need to be renamed
now, or any new luatex-using packages will use (are using) the current
names, and we will be completely stuck by the time luatex is widely
deployed -- there will be too many packages.

I don't think the renamed primitives should have @ in the name.  They
aren't necessarily internal, that's an independent issue.  A prefix is
enough.  If some primitives are shared between engines or already have a
prefix, then that is fine, we don't need to blindly prefix everything
with the same string.

I think it should be done for both plain and latex, that is,
(pdf)luatex.fmt and (pdf)lualatex.fmt.

Elie?

karl

P.S. The answer to the various questions of "when does this ever cause a
problem" is simple: any existing latex document that issues the
perfectly reasonable construct \newcommand{\primitive}{...} fails.