fact: Variable monoid_opt : QueueMonoidOpt monoid bool.
imports: Fiat.Computation Fiat.Narcissus.Common.Specs Fiat.Narcissus.Common.Notations Fiat.Narcissus.Common.ComposeOpt Fiat.Narcissus.Common.WordFacts Fiat.Narcissus.Formats.WordOpt Fiat.Narcissus.BaseFormats