proposition: Lemma to_of_string str : to_string (of_string str) = str.
proof: Proof. induction str. { unfold fold, fold'. rewrite of_string_length; simpl. reflexivity. } { rewrite fold_recr. rewrite get_of_string; simpl. rewrite drop_of_string; simpl. rewrite IHstr. reflexivity. } Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Coq.ZArith.ZArith Fiat.Common Fiat.Common.List.Operations Fiat.Common.List.ListFacts Fiat.Common.Le Fiat.Common.Tactics.SetoidSubst Fiat.Common.Tactics.IsClosed Fiat.Parsers.StringLike.Core Fiat.Common.UIP