Karl
> LaTeXers - personally, I think it would be nice if the "primitive
> requirements" became a permanent part of the LaTeX
> documentation. (Apologies if they already there.) Maybe?
any suggestion where that should be? I consider ltnews actually not a
bad place especially as there is also
https://www.latex-project.org/news/latex2e-news/ltnews.pdf
which puts them all together.
more for @Thierry ...
It might be possible to make a distinction between primitives that are
specific to pdf generation (because they are not relevant if dvi is
produced (which we intend to support)) and those that are for general
coding, e.g. \ifincsname, \expanded or \pdfstrcmp (which has nothing to
do with "pdf" other than it was first introduced in pdftex) and a number
of others.
The general coding primitives are rather essential and for most of them
there is no way to emulate in any way that still allows a somewhat
reasonable performance even if technically TeX is Turing-complete.
In other words it should be possible to drop the primitives which are
really PDF output specific (if we list any of them as required) and
require them only for engines/engine-modes that target PDF directly and
make sure that the format doesn't complain if they aren't there, but
there is not reasonable way going forward without the general coding
ones that are now (fortunately) available in all major engines.
frank