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