I take issue with calling stack languages the inverse of Lisp. This isn't really the case since functions in stack languages are fixed arity, while Lisp functio

I take issue with calling stack languages the inverse of Lisp. This isn't really the case since functions in stack languages are fixed arity, while Lisp functions are not. The inverse of RPN would be the fixed-arity prefix notation used by the REBOL family of languages.