An interface to use for int-like types, e.g., Int and
Int64.
module type Round : sig ... endmodule type Hexable : sig ... endmodule type S_common : sig ... endmodule type Operators_unbounded : sig ... endmodule type Operators : sig ... endmodule type S_unbounded : sig ... endS_unbounded is a generic interface for unbounded integers, e.g. Bignum.Bigint.
S_unbounded is a restriction of S (below) that omits values that depend on
fixed-size integers.
include sig ... endmodule type Int : sig ... end