proposition: Lemma add_take_1_singleton (str : String) ch (H : str ~= [ ch ]) : take 1 str ~= [ ch ].
proof: Proof. rewrite take_long; [ assumption | ]. apply length_singleton in H; rewrite H; 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