(import match-generics)
(define-generic (frotz a b c) (list b a c))
(define-generic (frotz x y) (+ x y))
(unless
  (equal? '((2 1 3) 9) (list (frotz 1 2 3) (frotz 4 5)))
  (error "(list (frotz 1 2 3) (frotz 4 5))"))
(define-generic (my-map proc (x . xs)) (cons (proc x) (my-map proc xs)))
(define-generic (my-map proc ()) '())
(unless
  (equal? '(2 3 4) (my-map add1 '(1 2 3)))
  (error "(my-map add1 (quote (1 2 3)))"))
(define-generic (plus (? list? a) (? list? b)) (append a b))
(define-generic (plus (? string? a) (? string? b)) (string-append a b))
(define-generic (plus (? number? a) (? number? b)) (+ a b))
(unless
  (equal?
    '("1314" 29 32 (a b c 1 2 3))
    (list (plus "13" "14") (plus 7 22) (plus 13 19) (plus '(a b c) '(1 2 3))))
  (error "(list (plus \"13\" \"14\") (plus 7 22) (plus 13 19) (plus (quote (a b c)) (quote (1 2 3))))"))
(define-generic ((frobnicate a) b z) (list a b z))
(define-generic ((frobnicate a) b) (string-append a b))
(unless
  (equal?
    '(("hoho" 1 2) "hoho and such")
    (let ((hoho (frobnicate "hoho"))) (list (hoho 1 2) (hoho " and such"))))
  (error "(let ((hoho (frobnicate \"hoho\"))) (list (hoho 1 2) (hoho \" and such\")))"))