Guard patterns can be used to check that a value satisfies an arbitrary test-form.
(dotimes (i 5)
(format t "~d: ~a~%"
i (match i
((guard x (oddp x)) "Odd!")
(_ "Even!"))))
; 0: Even!
; 1: Odd!
; 2: Even!
; 3: Odd!
; 4: Even!