ucharcat package
Lua implementation of \Ucharcat, to match xetex's primitive.
To extract the ucharcat.sty package:
tex ucharcat.ins
David Carlisle
LPPL licenced (status: maintained)
Master source:
https://github.com/davidcarlisle/dpctex/tree/master/ucharcat
Please report any issues at
https://github.com/davidcarlisle/dpctex/issues