use a functor rather than first-class modules, for Set

sequence.ml

@@ -128,6 +128,8 @@ module List =
   struct
     let of_seq seq = List.rev (fold (fun y x -> x::y) [] seq)
 
+    let of_rev_seq seq = fold (fun y x -> x :: y) [] seq
+
     let to_seq l = from_iter (fun k -> List.iter k l)
   end
 
@@ -191,15 +193,16 @@ module Int =
       { seq_fun; }
   end
 
-module Set =
+(** Iterate on sets. The functor must be instantiated with a set type *)
+module Set(S : Set.S) =
   struct
-    let to_seq (type s) (type t) m set =
-      let module S = (val m : Set.S with type elt = s and type t = t) in
-      from_iter (fun k -> S.iter k set)
+    type set = S.t
 
-    let of_seq (type s) (type t) m seq =
-      let module S = (val m : Set.S with type elt = s and type t = t) in
-      fold (fun set x -> S.add x set) S.empty seq
+    type elt = S.elt
+
+    let to_seq set = from_iter (fun k -> S.iter k set)
+
+    let of_seq seq = fold (fun set x -> S.add x set) S.empty seq
   end
 
 (** {2 Pretty printing of sequences} *)

sequence.mli

@@ -85,6 +85,9 @@ module List :
   sig
     val of_seq : 'a t -> 'a list
 
+    val of_rev_seq : 'a t -> 'a list
+      (** Get the list of the reversed sequence (more efficient) *)
+
     val to_seq : 'a list -> 'a t
   end
 
@@ -146,11 +149,16 @@ module Int :
           sequences. *)
   end
 
-(** Iterate on sets. The Set module has to be provided. *)
-module Set :
+(** Iterate on sets. The functor must be instantiated with a set type *)
+module Set(S : Set.S) :
   sig
-    val to_seq : (module Set.S with type elt = 'a and type t = 'b) -> 'b -> 'a t
-    val of_seq : (module Set.S with type elt = 'a and type t = 'b) -> 'a t -> 'b
+    type set = S.t
+    
+    type elt = S.elt
+    
+    val to_seq : set -> elt t
+
+    val of_seq : elt t -> set
   end
 
 (** {2 Pretty printing of sequences} *)

tests.ml

@@ -7,6 +7,7 @@ let pp_list ?(sep=", ") pp_item formatter l =
 
 (** Set of integers *)
 module ISet = Set.Make(struct type t = int let compare = compare end)
+module ISetSeq = Sequence.Set(ISet)
 
 let _ =
   let l = [0;1;2;3;4;5;6] in
@@ -24,12 +25,12 @@ let _ =
   in
   let l3 = Sequence.List.of_seq (Sequence.rev (Sequence.Int.range ~start:0 ~stop:42)) in
   let set = List.fold_left (fun set x -> ISet.add x set) ISet.empty [4;3;100;42] in
-  let s = (module ISet : Set.S with type elt = int and type t = ISet.t) in
-  let l4 = Sequence.List.of_seq (Sequence.Set.to_seq s set) in
+  let l4 = Sequence.List.of_seq (ISetSeq.to_seq set) in
   Format.printf "l=@[<h>[%a]@]@." (pp_list Format.pp_print_int) l;
   Format.printf "l'=@[<h>[%a]@]@." (pp_list Format.pp_print_int) l';
   Format.printf "l''=@[<h>[%a]@]@." (pp_list Format.pp_print_int) l'';
   Format.printf "l2=@[<h>[%a]@]@." (pp_list Format.pp_print_string) l2;
   Format.printf "l3=@[<h>[%a]@]@." (pp_list Format.pp_print_int) l3;
+  Format.printf "s={@[<h>%a@]}@." (Sequence.pp_seq Format.pp_print_int) (ISetSeq.to_seq set);
   Format.printf "l4=@[<h>[%a]@]@." (pp_list Format.pp_print_int) l4;
   ()