対話によるCommon Lisp 7.10
CL-USER> (defun compute (form) (if (atom form) form (case (second form) (+ (+ (compute (first form)) (compute (third form)))) (- (- (compute (first form)) (compute (third form)))) (* (* (compute (first form)) (compute (third form)))) (/ (/ (compute (first form)) (compute (third form)))) (otherwise)))) COMPUTE CL-USER> (compute '(/ 10 2)) NIL CL-USER> (compute '(10 / 2)) 5
caseないので・・・