# Module Set

    module Set: sig .. end

Sets over ordered types.

This module implements the set data structure, given a total ordering function over the set elements. All operations over sets are purely applicative (no side-effects). The implementation uses balanced binary trees, and is therefore reasonably efficient: insertion and membership take time logarithmic in the size of the set, for instance.

The `Set.Make` functor constructs implementations for any type, given a `compare` function. For instance:

         module IntPairs =
           struct
             type t = int * int
             let compare (x0,y0) (x1,y1) =
               match Pervasives.compare x0 x1 with
                   0 -> Pervasives.compare y0 y1
                 | c -> c
           end

         module PairsSet = Set.Make(IntPairs)

         let m = PairsSet.(empty |> add (2,3) |> add (5,7) |> add (11,13))

This creates a new module `PairsSet`, with a new type `PairsSet.t` of sets of `int * int`.

    module type OrderedType = sig .. end

Input signature of the functor `Set.Make`.

    module type S = sig .. end

Output signature of the functor `Set.Make`.

    module Make: functor (Ord : OrderedType) -> S  with type elt = Ord.t

Functor building an implementation of the set structure given a totally ordered type.