look up value in association list, using eq as test
Major Section:  PROGRAMMING

(Rassoc-eq x alist) is similar to (assoc-eq x alist), the difference being that it looks for the first pair in the given alist whose cdr, rather than car, is eq to x. See assoc.

The guard of rassoc-eq requires its second argument to be an alist, and in addition, that either its first argument is a symbolp or else all second components of pairs belonging to the second argument are symbolps.

Rassoc is a Common Lisp function. See any Common Lisp documentation for more information.