Patternsval omega : Typedtree.patternaka. "Tpat_any" or "_"
val omegas : int -> Typedtree.pattern listList.init (fun _ -> omega)
val omega_list : 'a list -> Typedtree.pattern listList.map (fun _ -> omega)
module Non_empty_row : sig ... endmodule Simple : sig ... endmodule Half_simple : sig ... endmodule General : sig ... endmodule Head : sig ... end