(** Properties of to_list and of_list *)

(* Specifications: *)
Lemma of_list_length (l : list char63) :
Z.of_nat (List.length l) <= to_Z max_length ->
length (of_list l) = of_Z (Z.of_nat (List.length l)).
Lemma of_list_app (l1 l2 : list char63) :
of_list (l1 ++ l2) = cat (of_list l1) (of_list l2).
Lemma to_list_cat (s1 s2 : string) :
(to_Z (length s1) + to_Z (length s2) <= to_Z max_length)%Z ->
to_list (cat s1 s2) = app (to_list s1) (to_list s2).