XINAL will be a new dialect of Lisp. Arc Lisp is taking too long, and I'm impatient. I'll put more info here as I proceed on the project.
XINAL will work by having a subset of XINAL written in C, and then actual XINAL written in this sub-XINAL language. By having a special environment frame accesible to the user's code that is synchronized with a frame in the sub-XINAL environment that XINAL runs in, it will be possible to spectacularly break things.