+val box: int -> unit
+
+val unbox: int -> unit
+
+val flush: int -> unit
+
+val box_err: unit -> unit
+
+val flush_err: unit -> unit
+
+val log: ('a, 'b) specs -> int -> ('a, 'b) message -> unit
+
+val error: ('a, 'b) specs -> ('a, 'b) message -> unit
+
+val items1: string -> ('a, 'b) message