Functional variant of 'oneof' function in Racket

Question

I have written following function to find if one and only one of 5 variables is true:

(define (oneof v w x y z)
  (or (and v (not w) (not x) (not y)  (not z         


        

Answer 1

Another solution, more concise, is the following:

(define (oneof . vars)
  (= 1 (count identity vars)))