# [NTG-pdftex] \pdfprimitive

Taco Hoekwater taco at elvenkind.com
Sun Apr 8 09:52:29 CEST 2007

Vladimir Volovich wrote:
> "TH" == Taco Hoekwater writes:
>
>  TH> In LuaTeX I will follow the eTeX paradigm, and this particular
>  TH> command will be called \primitive. Only PDF-related commands will
>  TH> have a \pdf prefix.
>
> and LuaTeX later is going to be merged into pdftex...

Not merged so much as superceded. There is a traditional pdftex 1.50
yet to come, and that will be around (and bugfixed) forever.

LuaTeX's executable will continue to be named luatex, but it will
internally present itself as \pdftexversion = 2 (as well as other
version identifiers).

General policy note:

I feel free to make some changes that break compatibility on both
the input and the output side, because the major version number (as
well as the executable name) will be changed. If I did not have that
liberty, lots of things would simply not be doable.

I have already removed a few of the most recent extension primitives,
because the functionality can better be handled by lua scripting.
Think of \pdfelapsedtime and \pdffilesize.

The syntax of the \font primitive in luatex has also changed, it now
accepts a brace group as 'font identifier'. Without that change,
I would have had to invent a completely new way of specifying fonts,
and that would have been enormously confusing to both users and
macro programmers.

Luatex is *not* going to be identical to pdftex 1.xx. It will be
as compatible as is reasonable, but such compatibility is not the
first goal. The top spot is reserved for creating new functionality.
The second spot is for creating a clean base for even more development.
Compatibility comes somewhere below that.

People that want 100% pdftex, should stick with pdftex.

> if you will have renamed most of them (with stripped "pdf" at the
> beginning), it will create another messy situation.
>
> so it seems safer to stick to the already used names, otherwise there

I will consider creating aliases, but since that can just as easily
be done by a macro package (using \protected\def), it is not very
high on my todo list. Looking back on how LaTeX has handled new engines
in the past, it is a very safe bet to assume that a \usepackage{luatex}
or a separate 'corona.fmt' will be required to make use of the new
features, anyway.

Best wishes,
Taco