proposition: Lemma nth_to_string s n : List.nth_error (to_string s) n = get n s.
proof: Proof. rewrite get_drop. symmetry. take_drop_to_string_t s n; try solve [ apply has_first_char_nonempty; rewrite ?drop_length; omega ]. 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