generic sequence pretty-printing function

sequence.ml

@@ -201,3 +201,16 @@ module Set =
       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
   end
+
+(** {2 Pretty printing of sequences} *)
+
+(** Pretty print a sequence of ['a], using the given pretty printer
+    to print each elements. An optional separator string can be provided. *)
+let pp_seq ?(sep=", ") pp_elt formatter seq =
+  let first = ref true in
+  iter
+    (fun x -> 
+      (if !first then first := false else Format.pp_print_string formatter sep);
+      pp_elt formatter x;
+      Format.pp_print_cut formatter ())
+    seq

sequence.mli

@@ -152,3 +152,10 @@ module Set :
     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
   end
+
+(** {2 Pretty printing of sequences} *)
+
+val pp_seq : ?sep:string -> (Format.formatter -> 'a -> unit) ->
+             Format.formatter -> 'a t -> unit
+  (** Pretty print a sequence of ['a], using the given pretty printer
+      to print each elements. An optional separator string can be provided. *)

tests.ml

@@ -2,11 +2,8 @@
 (** {2 Test sequences} *)
 
 (** print a list of items using the printing function *)
-let rec pp_list ?(sep=", ") pp_item formatter = function
+let pp_list ?(sep=", ") pp_item formatter l = 
-  | x::y::xs -> Format.fprintf formatter "%a%s@,%a"
+  Sequence.pp_seq ~sep pp_item formatter (Sequence.List.to_seq l)
-      pp_item x sep (pp_list ~sep:sep pp_item) (y::xs)
-  | x::[] -> pp_item formatter x
-  | [] -> ()
 
 (** Set of integers *)
 module ISet = Set.Make(struct type t = int let compare = compare end)