[ Course Documents ] : [ FP Foundations, Scheme ]

Previous Contents Next Keyword Index

Example Scheme Fns: equal

• equal takes two lists as parameters; returns #T if the two general lists are equal; () otherwise

      (define (equal lis1 lis2)
          (cond
              ((not (list? lis1))   (eqv? lis1 lis2))
              ((not (list? lis2))   '())
              ((null? lis1)         (null? lis2))
              ((null? lis2)         '())
              ((equal (car lis1) (car lis2))
                                    (equal (cdr lis1) (cdr lis2)))
              (else                 '())
          )
      )