Config.EnvVarmodule M : sig ... endinclude module type of struct include M endtype t = M.tval name : Base.stringval doc : Base.stringval default : tval parse : Base.string -> tval unparse : t -> Base.stringval opt_value : t Base.Option.tval get_opt : unit -> t Base.Option.tval get : unit -> tval doc_info : 'a variable_doc