[XeTeX] The future of XeTeX

[Philip TAYLOR]

Joel C. Salomon wrote:

> I know for a fact that LuaTeX enables features of OpenType Math fonts
> that XeTeX does not. See, e.g.,
> <https://github.com/wspr/unicode-math/issues/40>.
>
> And, of course, there are XeTeX-specific features (most prominently
> interchartoks) which LuaTeX does not implement.
>
> Avoiding math and engine-specific extensions, I personally have not
> *noticed* any differences between the outputs, but given the
> differences that exist I doubt anyone would care to guarantee
> identical results.

OK, but how about things such as graphics ?  I already know
that I cannot use (e.g.,) \pdfximage, \pdfrefximage and
\pdflastximage in XeTeX, and have to use instead \XeTeXpicfile;
if I were to migrate to LuaTeX, would I be correct in expecting
to find a whole new set of graphics primitives ?  And what of
\XeTeX's extensions to the \font primitive ?

** Phil.