module type EqSig =
sig
  type t;;
  val equal : t -> t -> bool
end;;

module EqInt : EqSig with type t = int =
struct
  type t = int;;
  let equal = (=);;
end;;

module BigFunctor(E : EqSig) =
struct
  let eqall x y z = E.equal x y && E.equal y z;;
  let alldiff x y z = not (E.equal x y) &&
                      not (E.equal x z) &&
                      not (E.equal y z);;
end;;

module type FactoredFunctorPart1Sig =
sig
  module E : EqSig
  val eqall : E.t -> E.t -> E.t -> bool
end;;

module FactoredFunctorPart1(E : EqSig) :
  FactoredFunctorPart1Sig with module E = E
=
struct
  module E = E
  let eqall x y z = E.equal x y && E.equal y z;;
end;;

module type FactoredFunctorPart2Sig =
sig
  module E : EqSig
  val alldiff : E.t -> E.t -> E.t -> bool
end;;

module FactoredFunctorPart2(E : EqSig) :
  FactoredFunctorPart2Sig with module E = E
=
struct
  module E = E
  let alldiff x y z = not (E.equal x y) &&
                      not (E.equal x z) &&
                      not (E.equal y z);;
end;;

module FactoredFunctor(E : EqSig) =
struct
  include (FactoredFunctorPart1(E) : FactoredFunctorPart1Sig with module E := E);;
  include (FactoredFunctorPart2(E) : FactoredFunctorPart2Sig with module E := E);;
end;;