(* Find out whether a list is a palindrome. A palindrome can be read forward or backward; e.g. (x a m a x). *)

let rec compare_lists l1 l2 =
        match (l1,l2) with
                ([],[]) -> true
        |       (h1::t1,h2::t2) ->
                        if( h1 = h2 ) 
                        then ( compare_lists t1 t2 )
                        else false
        |       (l1,l2) -> false
;;

let is_palindrom l = compare_lists l ( List.rev l );;

(* test *)
Printf.printf "abcba is a palindrom : %b\n"
        ( is_palindrom ["a";"b";"c";"b";"a"] );;