cartesian product of lists

cart.scm

(define (product . args)                                                             
  (if (null? args)                                                                   
      (list '())                                                                     
      (apply append                                                                  
              (map (lambda (rest)                                                    
                    (map (lambda (first)                                             
                            (cons first rest))                                       
                          (car args)))                                               
                  (apply product (cdr args))))))