CL-USER> (defvar *arch-enemy* nil)
(defun pudding-eater (person)
(cond ((eq person 'henry)(setf *arch-enemy* 'stupid-lisp-alien)'(curse you lisp alien - you ate my pudding))
((eq person 'johnny)(setf *arch-enemy* 'useless-old-johnny)'(i hope you choked on my pudding johnny))
(t'(why you ate my pudding stranger?))))
PUDDING-EATER
CL-USER> *arch-enemy*
NIL
CL-USER> (pudding-eater 'johnny)
(I HOPE YOU CHOKED ON MY PUDDING JOHNNY)
CL-USER> *arch-enemy*
USELESS-OLD-JOHNNY
CL-USER>