All ints must be defined before all dimens
Other than \expanded, all of the suggestioned additions are already in pdfTeX (as \pdf...) and are documented in the pdfTeX manual. For \expanded, what the team wrote will go into the manual for pdfTeX: https://www.tug.org/svn/pdftex/branches/stable/doc/manual/pdftex-t.tex?r1=801&r2=800&pathrev=801. Broadly, it does the same expansion as \message but is expandable.
Any news on this: we (LaTeX team) are rolling out using \expanded in other engines.
To add that the primitive names are all minus the 'pdf' prefix, as for e.g. \strcmp (= \pdfstrcmp).
Note that this merge request builds on https://sourceforge.net/p/xetex/code/merge-requests/2/ (and thus on https://sourceforge.net/p/xetex/code/merge-requests/1/).
Note that this merge request builds on https://sourceforge.net/p/xetex/code/merge-requests/1/
Extend \Ucharcat to produce \active chars
Extend \Ucharcat to active chars