Simply false. For example, LISP 1.5 manual had this definition for UNION: (union (lambda (x y) (cond ((null x) y) ((member (car x) y) (union (cdr x)

Simply false. For example, LISP 1.5 manual had this definition for UNION: (union (lambda (x y) (cond ((null x) y) ((member (car x) y) (union (cdr x) y)) (t (cons (car x) (union (cdr x) y)))))) It had a MAPLIST (today called MAPCAR): maplist[x;fn]=[null[x]->NIL; t->cons[fn[x];maplist[cdr[x];fn]]] Or APPEND: append[x;y] = [null[x] -> y; T -> cons[car[x]; append[cdr[x];y]]] Et cetera. Sure, it also had, say, NCONC. But it had these operators and style from the beginning, not surprisingly, as Lisp came from lambda calculus.