# Module type Comparable_intf.S

    module type S = sig .. end

Usage example:

          module Foo : sig
            type t = ...
            include Comparable.S with type t := t
          end

Then use `Comparable.Make` in the struct (see comparable.mli for an example).

    include Comparable_intf.S_common

    module Map: Core_map.S
        with type Key.t = t
        with type Key.comparator_witness = comparator_witness

    module Set: Core_set.S
        with type Elt.t = t
        with type Elt.comparator_witness = comparator_witness