From d0c3af549247a9588d1feb75580e25260ceeb520 Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Sat, 13 Dec 2014 03:11:16 +0100
Subject: [PATCH] continue removal of CCGen/CCsequence

---
 _oasis                          |  12 +--
 advanced/CCLinq.ml              | 104 +++++++++++------------
 benchs/bench_conv.ml            |   4 +-
 benchs/run_benchs.ml            |  12 +--
 core/CCBV.ml                    |   2 +-
 core/CCIO.ml                    |  56 ++++++++++--
 core/CCVector.ml                |   4 +-
 examples/mem_size.ml            |   2 +-
 misc/absSet.ml                  |  16 ++--
 misc/absSet.mli                 |  14 +--
 misc/circList.ml                |   2 +-
 misc/fHashtbl.ml                |  24 +++---
 misc/fHashtbl.mli               |   6 +-
 misc/flatHashtbl.ml             |  13 +--
 misc/flatHashtbl.mli            |   6 +-
 misc/hashset.ml                 |  12 ++-
 misc/hashset.mli                |   6 +-
 misc/heap.ml                    |   2 +
 misc/heap.mli                   |   6 +-
 misc/lazyGraph.ml               | 146 +++++++++++++++++++-------------
 misc/lazyGraph.mli              |  30 ++++---
 misc/pHashtbl.ml                |  10 +--
 misc/pHashtbl.mli               |   8 +-
 misc/parseReact.ml              |   2 +-
 misc/persistentGraph.ml         |  79 +++++++++--------
 misc/persistentGraph.mli        |  22 ++---
 misc/skipList.ml                |   8 +-
 misc/skipList.mli               |   6 +-
 misc/smallSet.ml                |  12 ++-
 misc/smallSet.mli               |   7 +-
 misc/splayMap.ml                |  20 +++--
 misc/splayMap.mli               |  11 ++-
 tests/run_tests.ml              |   1 -
 tests/test_CCHeap.ml            |   2 -
 tests/test_PersistentHashtbl.ml |   1 -
 tests/test_bv.ml                |   2 +-
 tests/test_deque.ml             |   2 +-
 tests/test_fHashtbl.ml          |   2 +-
 tests/test_fQueue.ml            |   2 +-
 tests/test_flatHashtbl.ml       |   2 +-
 tests/test_gen.ml               | 132 -----------------------------
 tests/test_graph.ml             |   2 +-
 tests/test_heap.ml              |   2 +-
 tests/test_mixtbl.ml            |   6 +-
 tests/test_pHashtbl.ml          |   2 +-
 tests/test_splayMap.ml          |   2 +-
 tests/test_vector.ml            |   2 +-
 tests/threads/test_future.ml    |   6 +-
 48 files changed, 415 insertions(+), 417 deletions(-)
 delete mode 100644 tests/test_gen.ml

diff --git a/_oasis b/_oasis
index 6386f2b3..104e273b 100644
--- a/_oasis
+++ b/_oasis
@@ -86,12 +86,12 @@ Library "containers_advanced"
   Modules:          CCLinq, CCBatch, CCCat, CCMonadIO
   FindlibName:      advanced
   FindlibParent:    containers
-  BuildDepends:     containers
+  BuildDepends:     containers, sequence
 
 Library "containers_pervasives"
   Path:             pervasives
   Modules:          CCPervasives
-  BuildDepends:     containers, 
+  BuildDepends:     containers
   FindlibName:      pervasives
   FindlibParent:    containers
 
@@ -185,7 +185,7 @@ Executable run_benchs
   Build$:           flag(bench) && flag(misc)
   MainIs:           run_benchs.ml
   BuildDepends:     containers, containers.misc, containers.advanced,
-                    containers.string, benchmark
+                    containers.string, sequence, gen, benchmark
 
 Executable bench_hash
   Path: benchs/
@@ -201,7 +201,7 @@ Executable bench_conv
   CompiledObject: native
   Build$: flag(bench)
   MainIs: bench_conv.ml
-  BuildDepends: containers,benchmark
+  BuildDepends: containers,benchmark,gen
 
 Executable test_levenshtein
   Path: tests/
@@ -236,7 +236,7 @@ Executable run_qtest
   MainIs:           run_qtest.ml
   Build$:           flag(tests)
   BuildDepends:     containers, containers.misc, containers.string,
-                    oUnit, QTest2Lib
+                    sequence, gen, oUnit, QTest2Lib
 
 Executable run_tests
   Path: tests/
@@ -244,7 +244,7 @@ Executable run_tests
   CompiledObject: native
   MainIs: run_tests.ml
   Build$: flag(tests) && flag(misc)
-  BuildDepends: containers, oUnit, qcheck, containers.misc
+  BuildDepends: containers, oUnit, sequence, gen, qcheck, containers.misc
 
 Test all
   Command:      make test-all
diff --git a/advanced/CCLinq.ml b/advanced/CCLinq.ml
index 17cf74de..82433e3d 100644
--- a/advanced/CCLinq.ml
+++ b/advanced/CCLinq.ml
@@ -43,7 +43,7 @@ let _error_of_exn f = try `Ok (f ()) with ExitWithError s -> `Error
 type 'a collection =
   | Seq : 'a sequence -> 'a collection
   | List : 'a list -> 'a collection
-  | Set : (module CCSequence.Set.S
+  | Set : (module Sequence.Set.S
            with type elt = 'a and type t = 'b) * 'b -> 'a collection
 
 module PMap = struct
@@ -103,7 +103,7 @@ module PMap = struct
     }
 
   let make_cmp (type key) ?(cmp=Pervasives.compare) () =
-    let module M = CCSequence.Map.Make(struct
+    let module M = Sequence.Map.Make(struct
       type t = key
       let compare = cmp
     end) in
@@ -167,26 +167,26 @@ module PMap = struct
       | None -> None
       | Some v -> Some (f v)
     );
-    to_seq = CCSequence.map (fun (x,y) -> x, f y) m.to_seq;
+    to_seq = Sequence.map (fun (x,y) -> x, f y) m.to_seq;
     fold = (fun f' acc ->
       m.fold (fun acc x y -> f' acc x (f y)) acc
     );
   }
 
-  let to_list m = CCSequence.to_rev_list m.to_seq
+  let to_list m = Sequence.to_rev_list m.to_seq
 
   let to_coll m = Seq m.to_seq
 
   let reverse ~build m =
     let build = make ~build () in
-    let seq = CCSequence.map (fun (x,y) -> y,x) (to_seq m) in
+    let seq = Sequence.map (fun (x,y) -> y,x) (to_seq m) in
     multimap_of_seq ~build seq
 
   let reverse_multimap ~build m =
     let build = make ~build () in
     let seq = to_seq m in
-    let seq = CCSequence.flat_map
-        (fun (x,l) -> CCSequence.map (fun y -> y,x) (CCSequence.of_list l)
+    let seq = Sequence.flat_map
+        (fun (x,l) -> Sequence.map (fun y -> y,x) (Sequence.of_list l)
         ) seq
     in
     multimap_of_seq ~build seq
@@ -211,10 +211,10 @@ type ('a,'b) group_join_descr = {
 module Coll = struct
   let of_seq s = Seq s
   let of_list l = List l
-  let of_array a = Seq (CCSequence.of_array a)
+  let of_array a = Seq (Sequence.of_array a)
 
   let set_of_seq (type elt) ?(cmp=Pervasives.compare) seq =
-    let module S = CCSequence.Set.Make(struct
+    let module S = Sequence.Set.Make(struct
       type t = elt
       let compare = cmp
     end) in
@@ -225,15 +225,15 @@ module Coll = struct
     | Seq s -> s
     | List l -> (fun k -> List.iter k l)
     | Set (m, set) ->
-        let module S = (val m : CCSequence.Set.S
+        let module S = (val m : Sequence.Set.S
              with type elt = elt and type t = 'b) in
         S.to_seq set
 
   let to_list (type elt) = function
-    | Seq s -> CCSequence.to_list s
+    | Seq s -> Sequence.to_list s
     | List l -> l
     | Set (m, set) ->
-        let module S = (val m : CCSequence.Set.S
+        let module S = (val m : Sequence.Set.S
              with type elt = elt and type t = 'b) in
         S.elements set
 
@@ -245,30 +245,30 @@ module Coll = struct
 
   let fold (type elt) f acc c = match c with
     | List l -> List.fold_left f acc l
-    | Seq s -> CCSequence.fold f acc s
+    | Seq s -> Sequence.fold f acc s
     | Set (m, set) ->
-        let module S = (val m : CCSequence.Set.S
+        let module S = (val m : Sequence.Set.S
              with type elt = elt and type t = 'b) in
         S.fold (fun x acc -> f acc x) set acc
 
   let map f c =
-    _fmap ~lst:(List.map f) ~seq:(CCSequence.map f) c
+    _fmap ~lst:(List.map f) ~seq:(Sequence.map f) c
 
   let filter p c =
-    _fmap ~lst:(List.filter p) ~seq:(CCSequence.filter p) c
+    _fmap ~lst:(List.filter p) ~seq:(Sequence.filter p) c
 
   let flat_map f c =
     let c' = to_seq c in
-    Seq (CCSequence.flatMap (fun x -> to_seq (f x)) c')
+    Seq (Sequence.flatMap (fun x -> to_seq (f x)) c')
 
   let filter_map f c =
-    _fmap ~lst:(CCList.filter_map f) ~seq:(CCSequence.fmap f) c
+    _fmap ~lst:(CCList.filter_map f) ~seq:(Sequence.fmap f) c
 
   let size (type elt) = function
     | List l -> List.length l
-    | Seq s -> CCSequence.length s
+    | Seq s -> Sequence.length s
     | Set (m, set) ->
-        let module S = (val m : CCSequence.Set.S
+        let module S = (val m : Sequence.Set.S
              with type elt = elt and type t = 'b) in
         S.cardinal set
 
@@ -278,12 +278,12 @@ module Coll = struct
     | List [] -> fail ()
     | List (x::_) -> x
     | Seq s ->
-        begin match CCSequence.to_list (CCSequence.take 1 s) with
+        begin match Sequence.to_list (Sequence.take 1 s) with
         | [x] -> x
         | _ -> fail ()
         end
     | Set (m, set) ->
-        let module S = (val m : CCSequence.Set.S
+        let module S = (val m : Sequence.Set.S
              with type elt = elt and type t = 'b) in
         try S.choose set with Not_found -> fail ()
 
@@ -292,7 +292,7 @@ module Coll = struct
     with ExitWithError s -> `Error s
 
   let take n c =
-    _fmap ~lst:(CCList.take n) ~seq:(CCSequence.take n) c
+    _fmap ~lst:(CCList.take n) ~seq:(Sequence.take n) c
 
   exception MySurpriseExit
 
@@ -308,7 +308,7 @@ module Coll = struct
 
   let sort cmp c = match c with
     | List l -> List (List.sort cmp l)
-    | Seq s -> List (List.sort cmp (CCSequence.to_rev_list s))
+    | Seq s -> List (List.sort cmp (Sequence.to_rev_list s))
     | _ -> set_of_seq ~cmp (to_seq c)
 
   let search obj c =
@@ -328,9 +328,9 @@ module Coll = struct
 
   let contains (type elt) ~eq x c = match c with
     | List l -> List.exists (eq x) l
-    | Seq s -> CCSequence.exists (eq x) s
+    | Seq s -> Sequence.exists (eq x) s
     | Set (m, set) ->
-        let module S = (val m : CCSequence.Set.S
+        let module S = (val m : Sequence.Set.S
              with type elt = elt and type t = 'b) in
         (* XXX: here we don't use the equality relation *)
         S.mem x set
@@ -338,10 +338,10 @@ module Coll = struct
   let do_join ~join c1 c2 =
     let build1 =
       let seq = to_seq c1 in
-      let seq = CCSequence.map (fun x -> join.join_key1 x, x) seq in
+      let seq = Sequence.map (fun x -> join.join_key1 x, x) seq in
       PMap.multimap_of_seq ~build:(PMap.make ~build:join.join_build ()) seq
     in
-    let l = CCSequence.fold
+    let l = Sequence.fold
       (fun acc y ->
         let key = join.join_key2 y in
         match PMap.get build1 key with
@@ -373,14 +373,14 @@ module Coll = struct
 
   let do_product c1 c2 =
     let s1 = to_seq c1 and s2 = to_seq c2 in
-    of_seq (CCSequence.product s1 s2)
+    of_seq (Sequence.product s1 s2)
 
   let do_union ~build c1 c2 =
     let build = PMap.make ~build () in
     to_seq c1 (fun x -> PMap.add build x ());
     to_seq c2 (fun x -> PMap.add build x ());
     let seq = PMap.to_seq (PMap.build_get build) in
-    of_seq (CCSequence.map fst seq)
+    of_seq (Sequence.map fst seq)
 
   type inter_status =
     | InterLeft
@@ -408,7 +408,7 @@ module Coll = struct
     let map = PMap.build_get build in
     (* output elements of [c1] not in [map] *)
     let seq = to_seq c1 in
-    of_seq (CCSequence.filter (fun x -> not (PMap.mem map x)) seq)
+    of_seq (Sequence.filter (fun x -> not (PMap.mem map x)) seq)
 end
 
 (** {2 Query operators} *)
@@ -478,22 +478,22 @@ let of_array a =
   Start (Coll.of_array a)
 
 let of_array_i a =
-  Start (Coll.of_seq (CCSequence.of_array_i a))
+  Start (Coll.of_seq (Sequence.of_array_i a))
 
 let of_hashtbl h =
-  Start (Coll.of_seq (CCSequence.of_hashtbl h))
+  Start (Coll.of_seq (Sequence.of_hashtbl h))
 
 let of_seq seq =
   Start (Coll.of_seq seq)
 
 let of_queue q =
-  Start (Coll.of_seq (CCSequence.of_queue q))
+  Start (Coll.of_seq (Sequence.of_queue q))
 
 let of_stack s =
-  Start (Coll.of_seq (CCSequence.of_stack s))
+  Start (Coll.of_seq (Sequence.of_stack s))
 
 let of_string s =
-  Start (Coll.of_seq (CCSequence.of_str s))
+  Start (Coll.of_seq (Sequence.of_str s))
 
 (** {6 Execution} *)
 
@@ -553,7 +553,7 @@ let _do_unary : type a b. (a,b) unary -> a -> b
   | Fold (f, acc) -> Coll.fold f acc c
   | FoldMap (f, acc) -> PMap.fold f acc c
   | Reduce (safety, start, mix, stop) ->
-      let acc = CCSequence.fold
+      let acc = Sequence.fold
         (fun acc x -> match acc with
           | None -> Some (start x)
           | Some acc -> Some (mix x acc)
@@ -578,7 +578,7 @@ let _do_unary : type a b. (a,b) unary -> a -> b
   | Get (Implicit, k) -> PMap.get_exn c k
   | Get (Explicit, k) -> PMap.get_err c k
   | GroupBy (build,f) ->
-      let seq = CCSequence.map (fun x -> f x, x) (Coll.to_seq c) in
+      let seq = Sequence.map (fun x -> f x, x) (Coll.to_seq c) in
       PMap.multimap_of_seq ~build:(PMap.make ~build ()) seq
   | Contains (eq, x) -> Coll.contains ~eq x c
   | Count build ->
@@ -591,7 +591,7 @@ let _do_binary : type a b c. (a, b, c) binary -> a -> b -> c
   | GroupJoin gjoin -> Coll.do_group_join ~gjoin c1 c2
   | Product -> Coll.do_product c1 c2
   | Append ->
-      Coll.of_seq (CCSequence.append (Coll.to_seq c1) (Coll.to_seq c2))
+      Coll.of_seq (Sequence.append (Coll.to_seq c1) (Coll.to_seq c2))
   | SetOp (Inter,build) -> Coll.do_inter ~build c1 c2
   | SetOp (Union,build) -> Coll.do_union ~build c1 c2
   | SetOp (Diff,build) -> Coll.do_diff ~build c1 c2
@@ -695,8 +695,8 @@ module M = struct
 
   let flatten q =
     let f m =
-      let seq = CCSequence.flat_map
-        (fun (k,v) -> CCSequence.map (fun v' -> k,v') (Coll.to_seq v))
+      let seq = Sequence.flat_map
+        (fun (k,v) -> Sequence.map (fun v' -> k,v') (Coll.to_seq v))
          m.PMap.to_seq
       in Coll.of_seq seq
     in
@@ -704,8 +704,8 @@ module M = struct
 
   let flatten' q =
     let f m =
-      let seq = CCSequence.flatMap
-          (fun (k,v) -> CCSequence.map (fun v' -> k,v') (CCSequence.of_list v))
+      let seq = Sequence.flatMap
+          (fun (k,v) -> Sequence.map (fun v' -> k,v') (Sequence.of_list v))
           m.PMap.to_seq
       in Coll.of_seq seq
     in
@@ -885,16 +885,16 @@ let to_array q =
   QueryMap ((fun c -> Array.of_list (Coll.to_list c)), q)
 
 let to_seq q =
-  QueryMap ((fun c -> CCSequence.persistent (Coll.to_seq c)), q)
+  QueryMap ((fun c -> Sequence.persistent (Coll.to_seq c)), q)
 
 let to_hashtbl q =
-  QueryMap ((fun c -> CCSequence.to_hashtbl (Coll.to_seq c)), q)
+  QueryMap ((fun c -> Sequence.to_hashtbl (Coll.to_seq c)), q)
 
 let to_queue q =
-  QueryMap ((fun c q -> CCSequence.to_queue q (Coll.to_seq c)), q)
+  QueryMap ((fun c q -> Sequence.to_queue q (Coll.to_seq c)), q)
 
 let to_stack q =
-  QueryMap ((fun c s -> CCSequence.to_stack s (Coll.to_seq c)), q)
+  QueryMap ((fun c s -> Sequence.to_stack s (Coll.to_seq c)), q)
 
 module L = struct
   let of_list l = Start (Coll.of_list l)
@@ -909,7 +909,7 @@ module AdaptSet(S : Set.S) = struct
     return (Coll.of_seq (fun k -> S.iter k set))
 
   let to_set q =
-    let f c = CCSequence.fold (fun set x -> S.add x set) S.empty (Coll.to_seq c) in
+    let f c = Sequence.fold (fun set x -> S.add x set) S.empty (Coll.to_seq c) in
     query_map f q
 
   let run q = run (to_set q)
@@ -932,7 +932,7 @@ module AdaptMap(M : Map.S) = struct
 
   let to_map q =
     let f c =
-      CCSequence.fold (fun m (x,y) -> M.add x y m) M.empty (Coll.to_seq c)
+      Sequence.fold (fun m (x,y) -> M.add x y m) M.empty (Coll.to_seq c)
     in
     query_map f q
 
@@ -1008,13 +1008,13 @@ module IO = struct
     query_map f q
 
   let lines' q =
-    let f s = lazy (CCSequence.to_list (_lines s 0)) in
+    let f s = lazy (Sequence.to_list (_lines s 0)) in
     lazy_ (query_map f q)
 
   let _join ~sep ?(stop="") l =
     let buf = Buffer.create 128 in
     let seq = Coll.to_seq l in
-    CCSequence.iteri
+    Sequence.iteri
       (fun i x ->
         if i>0 then Buffer.add_string buf sep;
         Buffer.add_string buf x)
@@ -1035,7 +1035,7 @@ module IO = struct
 
   let out_lines oc q =
     let x = run_exn q in
-    CCSequence.iter (fun l -> output_string oc l; output_char oc '\n') (Coll.to_seq x)
+    Sequence.iter (fun l -> output_string oc l; output_char oc '\n') (Coll.to_seq x)
 
   let to_file_exn filename q =
     _with_file_out filename (fun oc -> out oc q)
diff --git a/benchs/bench_conv.ml b/benchs/bench_conv.ml
index c117fda8..7e958f36 100644
--- a/benchs/bench_conv.ml
+++ b/benchs/bench_conv.ml
@@ -79,11 +79,11 @@ let () =
   bench_list [1,2; 3,4; 5,6; 7,8; 9,10];
 
   let open CCFun in
-  let l = CCGen.(1 -- 100 |> map (fun x->x,x) |> to_rev_list) in
+  let l = Gen.(1 -- 100 |> map (fun x->x,x) |> to_rev_list) in
   Printf.printf "list of %d elements...\n" (List.length l);
   bench_list l;
 
-  let l = CCGen.(repeat Point.p |> take 10 |> to_rev_list) in
+  let l = Gen.(repeat Point.p |> take 10 |> to_rev_list) in
   Printf.printf "list of %d points...\n" (List.length l);
   bench_point_list l;
 
diff --git a/benchs/run_benchs.ml b/benchs/run_benchs.ml
index ec53abbd..3bde113e 100644
--- a/benchs/run_benchs.ml
+++ b/benchs/run_benchs.ml
@@ -480,8 +480,8 @@ module Iter = struct
   (** {2 Sequence/Gen} *)
 
   let bench_fold n =
-    let seq () = CCSequence.fold (+) 0 CCSequence.(0 --n) in
-    let gen () = CCGen.fold (+) 0 CCGen.(0 -- n) in
+    let seq () = Sequence.fold (+) 0 Sequence.(0 --n) in
+    let gen () = Gen.fold (+) 0 Gen.(0 -- n) in
     let klist () = CCKList.fold (+) 0 CCKList.(0 -- n) in
     CCBench.throughputN 3
       [ "sequence.fold", seq, ();
@@ -490,10 +490,10 @@ module Iter = struct
       ]
 
   let bench_flat_map n =
-    let seq () = CCSequence.(
+    let seq () = Sequence.(
       0 -- n |> flat_map (fun x -> x-- (x+10)) |> fold (+) 0
     )
-    and gen () = CCGen.(
+    and gen () = Gen.(
       0 -- n |> flat_map (fun x -> x-- (x+10)) |> fold (+) 0
     )
     and klist () = CCKList.(
@@ -509,12 +509,12 @@ module Iter = struct
   let bench_iter n =
     let seq () =
       let i = ref 2 in
-      CCSequence.(
+      Sequence.(
         1 -- n |> iter (fun x -> i := !i * x)
       )
     and gen () =
       let i = ref 2 in
-      CCGen.(
+      Gen.(
         1 -- n |> iter (fun x -> i := !i * x)
       )
     and klist () =
diff --git a/core/CCBV.ml b/core/CCBV.ml
index 37eeebb2..ac31693c 100644
--- a/core/CCBV.ml
+++ b/core/CCBV.ml
@@ -172,7 +172,7 @@ let iter_true bv f =
   done
 
 (*$T
-  of_list [1;5;7] |> iter_true |> CCSequence.to_list |> List.sort CCOrd.compare = [1;5;7]
+  of_list [1;5;7] |> iter_true |> Sequence.to_list |> List.sort CCOrd.compare = [1;5;7]
 *)
 
 let to_list bv =
diff --git a/core/CCIO.ml b/core/CCIO.ml
index 1ebe7064..7e19187e 100644
--- a/core/CCIO.ml
+++ b/core/CCIO.ml
@@ -28,6 +28,50 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 type 'a gen = unit -> 'a option  (** See {!CCGen} *)
 
+let gen_singleton x =
+  let done_ = ref false in
+  fun () -> if !done_ then None else (done_ := true; Some x)
+
+let gen_filter_map f gen =
+  (* tailrec *)
+  let rec next () =
+    match gen() with
+    | None -> None
+    | Some x ->
+        match f x with
+        | None -> next()
+        | (Some _) as res -> res
+  in next
+
+let gen_of_array arr =
+  let r = ref 0 in
+  fun () ->
+    if !r = Array.length arr then None
+    else (
+      let x = arr.(!r) in
+      incr r; 
+      Some x
+    )
+
+let gen_flat_map f next_elem =
+  let state = ref `Init in
+  let rec next() =
+    match !state with
+    | `Init -> get_next_gen()
+    | `Run gen ->
+      begin match gen () with
+      | None -> get_next_gen ()
+      | (Some _) as x -> x
+      end
+    | `Stop -> None
+  and get_next_gen() = match next_elem() with
+    | None -> state:=`Stop; None
+    | Some x ->
+        try state := `Run (f x); next()
+        with e -> state := `Stop; raise e
+  in
+  next
+
 let with_in ?(mode=0o644) ?(flags=[]) filename f =
   let ic = open_in_gen flags mode filename in
   try
@@ -165,8 +209,8 @@ module File = struct
     if Sys.is_directory d
     then
       let arr = Sys.readdir d in
-      CCGen.of_array arr
-    else CCGen.empty
+      gen_of_array arr
+    else fun () -> None
 
   let cons_ x tl =
     let first=ref true in
@@ -180,19 +224,19 @@ module File = struct
     if Sys.is_directory d
     then
       let arr = Sys.readdir d in
-      let tail = CCGen.of_array arr in
-      let tail = CCGen.flat_map
+      let tail = gen_of_array arr in
+      let tail = gen_flat_map
         (fun s -> walk (Filename.concat d s))
         tail
       in cons_ (`Dir,d) tail
-    else CCGen.singleton (`File, d)
+    else gen_singleton (`File, d)
 
   type walk_item = [`File | `Dir] * t
 
   let read_dir ?(recurse=false) d =
     if recurse
     then
-      CCGen.filter_map
+      gen_filter_map
         (function
           | `File, f -> Some f
           | `Dir, _ -> None
diff --git a/core/CCVector.ml b/core/CCVector.ml
index 143a5a55..f6cc9234 100644
--- a/core/CCVector.ml
+++ b/core/CCVector.ml
@@ -451,7 +451,7 @@ let of_seq ?(init=create ()) seq =
   init
 
 (*$T
-  of_seq CCSequence.(1 -- 10) |> to_list = CCList.(1 -- 10)
+  of_seq Sequence.(1 -- 10) |> to_list = CCList.(1 -- 10)
 *)
 
 let to_seq v k = iter k v
@@ -524,7 +524,7 @@ let to_gen v =
       ) else None
 
 (*$T
-  let v = (1--10) in to_list v = CCGen.to_list (to_gen v)
+  let v = (1--10) in to_list v = Gen.to_list (to_gen v)
   *)
 
 let of_klist ?(init=create ()) l =
diff --git a/examples/mem_size.ml b/examples/mem_size.ml
index d424e9ed..4e69c083 100644
--- a/examples/mem_size.ml
+++ b/examples/mem_size.ml
@@ -1,7 +1,7 @@
 (** Compute the memory footprint of a value (and its subvalues). Reference is
     http://rwmj.wordpress.com/2009/08/05/ocaml-internals-part-2-strings-and-other-types/ *)
 
-module Sequence = CCSequence
+
 
 (** A graph vertex is an Obj.t value *)
 let graph =
diff --git a/misc/absSet.ml b/misc/absSet.ml
index c8cbb06c..b8603320 100644
--- a/misc/absSet.ml
+++ b/misc/absSet.ml
@@ -25,6 +25,8 @@ for any direct, indirect, incidental, special, exemplary, or consequential
 
 (** {1 Abstract set/relation} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type 'a t = {
   mem : 'a -> bool;
   iter : ('a -> unit) -> unit;
@@ -102,8 +104,7 @@ let product s1 s2 =
   let cardinal () = s1.cardinal () * s2.cardinal () in
   { mem; iter; cardinal; }
 
-let to_seq set =
-  CCSequence.from_iter (fun k -> set.iter k)
+let to_seq set k = set.iter k
 
 let to_list set =
   let l = ref [] in
@@ -154,7 +155,7 @@ let builder_cmp (type k) ?(cmp=Pervasives.compare) () =
   mk_builder ~add ~get
 
 let of_seq_builder ~builder seq =
-  CCSequence.iter builder.add seq;
+  seq builder.add;
   builder.get ()
 
 let of_seq_hash ?eq ?hash seq =
@@ -165,7 +166,7 @@ let of_seq_cmp ?cmp seq =
   let b = builder_cmp ?cmp () in
   of_seq_builder b seq
 
-let of_list l = of_seq_hash (CCSequence.of_list l)
+let of_list l = of_seq_hash (fun k -> List.iter k l)
 
 let map ?(builder=builder_hash ()) set ~f =
   set.iter
@@ -202,7 +203,7 @@ module MakeHash(X : Hashtbl.HashedType) = struct
 
   let of_seq ?(size=5) seq =
     let h = Hashtbl.create size in
-    CCSequence.iter (fun x -> Hashtbl.add h x ()) seq;
+    seq (fun x -> Hashtbl.add h x ());
     let mem x = Hashtbl.mem h x in
     let iter k = Hashtbl.iter (fun x () -> k x) h in
     let cardinal () = Hashtbl.length h in
@@ -220,8 +221,9 @@ module MakeSet(S : Set.S) = struct
     mk_generic ~cardinal ~mem ~iter
 
   let of_seq ?(init=S.empty) seq =
-    let set = CCSequence.fold (fun s x -> S.add x s) init seq in
-    of_set set
+    let set = ref init in
+    seq (fun x -> set := S.add x !set);
+    of_set !set
 
   let to_set set =
     fold set S.empty (fun set x -> S.add x set)
diff --git a/misc/absSet.mli b/misc/absSet.mli
index 4bcec095..8ff8302a 100644
--- a/misc/absSet.mli
+++ b/misc/absSet.mli
@@ -25,6 +25,8 @@ for any direct, indirect, incidental, special, exemplary, or consequential
 
 (** {1 Abstract set/relation} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type 'a t
 
 val empty : 'a t
@@ -67,7 +69,7 @@ val intersection : 'a t -> 'a t -> 'a t
 val product : 'a t -> 'b t -> ('a * 'b) t
   (** Cartesian product *)
 
-val to_seq : 'a t -> 'a CCSequence.t
+val to_seq : 'a t -> 'a sequence
 
 val to_list : 'a t -> 'a list
 
@@ -93,13 +95,13 @@ val builder_hash : ?size:int ->
 
 val builder_cmp : ?cmp:('a -> 'a -> int) -> unit -> 'a builder
 
-val of_seq_builder : builder:'a builder -> 'a CCSequence.t -> 'a t
+val of_seq_builder : builder:'a builder -> 'a sequence -> 'a t
   (** Uses the given builder to construct a set from a sequence of elements *)
 
-val of_seq_hash : ?eq:('a -> 'a -> bool) -> ?hash:('a -> int) -> 'a CCSequence.t -> 'a t
+val of_seq_hash : ?eq:('a -> 'a -> bool) -> ?hash:('a -> int) -> 'a sequence -> 'a t
   (** Construction of a set from a sequence of hashable elements *)
 
-val of_seq_cmp : ?cmp:('a -> 'a -> int) -> 'a CCSequence.t -> 'a t
+val of_seq_cmp : ?cmp:('a -> 'a -> int) -> 'a sequence -> 'a t
   (** Construction of a set from a sequence of comparable elements *)
 
 val of_list : 'a list -> 'a t
@@ -133,7 +135,7 @@ module MakeHash(X : Hashtbl.HashedType) : sig
   type elt = X.t
     (** Elements of the set are hashable *)
 
-  val of_seq : ?size:int -> elt CCSequence.t -> elt t
+  val of_seq : ?size:int -> elt sequence -> elt t
     (** Build a set from a sequence *)
 end
 
@@ -141,7 +143,7 @@ end
 module MakeSet(S : Set.S) : sig
   type elt = S.elt
 
-  val of_seq : ?init:S.t -> elt CCSequence.t -> elt t
+  val of_seq : ?init:S.t -> elt sequence -> elt t
     (** Build a set from a sequence *)
 
   val of_set : S.t -> elt t
diff --git a/misc/circList.ml b/misc/circList.ml
index 9c795a98..0b0670be 100644
--- a/misc/circList.ml
+++ b/misc/circList.ml
@@ -124,7 +124,7 @@ let gen l =
 (*$Q
   (Q.list Q.small_int) (fun l -> \
     l = [] || let q = of_list l in \
-    gen q |> CCGen.take (List.length l) |> CCGen.to_list = l)
+    gen q |> Gen.take (List.length l) |> Gen.to_list = l)
   *)
 
 let seq l k =
diff --git a/misc/fHashtbl.ml b/misc/fHashtbl.ml
index fe1b3ea2..a72dd203 100644
--- a/misc/fHashtbl.ml
+++ b/misc/fHashtbl.ml
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Functional (persistent) hashtable} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 (** {2 Signatures} *)
 
 module type HASH = sig
@@ -64,9 +66,9 @@ module type S = sig
   val size : 'a t -> int
     (** Number of bindings *)
 
-  val to_seq : 'a t -> (key * 'a) CCSequence.t
+  val to_seq : 'a t -> (key * 'a) sequence
 
-  val of_seq : ?size:int -> (key * 'a) CCSequence.t -> 'a t
+  val of_seq : ?size:int -> (key * 'a) sequence -> 'a t
 end
 
 (** {2 Persistent array} *)
@@ -336,13 +338,13 @@ module Tree(X : HASH) = struct
   let size t =
     fold (fun n _ _ -> n + 1) 0 t
 
-  let to_seq t =
-    CCSequence.from_iter (fun k -> iter (fun key value -> k (key, value)) t)
+  let to_seq t k =
+    iter (fun key value -> k (key, value)) t
 
   let of_seq ?(size=32) seq =
-    CCSequence.fold
-      (fun t (k,v) -> replace t k v)
-      (empty size) seq
+    let cur = ref (empty size) in
+    seq (fun (k,v) -> cur := replace !cur k v);
+    !cur
 end
 
 (** {2 Flat hashtable} *)
@@ -492,10 +494,10 @@ module Flat(X : HASH) = struct
         | _ -> acc)
       acc t.buckets
 
-  let to_seq t =
-    CCSequence.from_iter
-      (fun k -> iter (fun key value -> k (key, value)) t)
+  let to_seq t k = iter (fun key value -> k (key, value)) t
 
   let of_seq ?(size=32) seq =
-    CCSequence.fold (fun t (k,v) -> replace t k v) (empty size) seq
+    let t = ref (empty size) in
+    seq (fun (k,v) -> t := replace !t k v);
+    !t
 end
diff --git a/misc/fHashtbl.mli b/misc/fHashtbl.mli
index 9bb7ca4f..27866813 100644
--- a/misc/fHashtbl.mli
+++ b/misc/fHashtbl.mli
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Functional (persistent) hashtable} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 (** {2 Signatures} *)
 
 module type HASH = sig
@@ -64,9 +66,9 @@ module type S = sig
   val size : 'a t -> int
     (** Number of bindings *)
 
-  val to_seq : 'a t -> (key * 'a) CCSequence.t
+  val to_seq : 'a t -> (key * 'a) sequence
 
-  val of_seq : ?size:int -> (key * 'a) CCSequence.t -> 'a t
+  val of_seq : ?size:int -> (key * 'a) sequence -> 'a t
 end
 
 (** {2 Persistent array} *)
diff --git a/misc/flatHashtbl.ml b/misc/flatHashtbl.ml
index b2e2ce8d..1ff59a21 100644
--- a/misc/flatHashtbl.ml
+++ b/misc/flatHashtbl.ml
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** Open addressing hashtable, with linear probing. *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 module type S =
   sig
     type key
@@ -61,9 +63,9 @@ module type S =
     val fold : (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
       (** Fold on bindings *)
 
-    val to_seq : 'a t -> (key * 'a) CCSequence.t
+    val to_seq : 'a t -> (key * 'a) sequence
 
-    val of_seq : 'a t -> (key * 'a) CCSequence.t -> unit
+    val of_seq : 'a t -> (key * 'a) sequence -> unit
 
     val stats : 'a t -> int * int * int * int * int * int
       (** Cf Weak.S *)
@@ -218,12 +220,11 @@ module Make(H : Hashtbl.HashedType) =
           | _ -> fold acc (i+1)
       in fold acc 0
 
-    let to_seq t =
-      CCSequence.from_iter
-        (fun k -> iter (fun key value -> k (key, value)) t)
+    let to_seq t k =
+      iter (fun key value -> k (key, value)) t
 
     let of_seq t seq =
-      CCSequence.iter (fun (k,v) -> replace t k v) seq
+      seq (fun (k,v) -> replace t k v)
 
     (** Statistics on the table *)
     let stats t = (Array.length t.buckets, t.size, t.size, 0, 0, 1)
diff --git a/misc/flatHashtbl.mli b/misc/flatHashtbl.mli
index 44f2c1f4..55b462a7 100644
--- a/misc/flatHashtbl.mli
+++ b/misc/flatHashtbl.mli
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** Open addressing hashtable, with linear probing. *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 module type S =
   sig
     type key
@@ -61,9 +63,9 @@ module type S =
     val fold : (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
       (** Fold on bindings *)
 
-    val to_seq : 'a t -> (key * 'a) CCSequence.t
+    val to_seq : 'a t -> (key * 'a) sequence
 
-    val of_seq : 'a t -> (key * 'a) CCSequence.t -> unit
+    val of_seq : 'a t -> (key * 'a) sequence -> unit
 
     val stats : 'a t -> int * int * int * int * int * int
       (** Cf Weak.S *)
diff --git a/misc/hashset.ml b/misc/hashset.ml
index 5ff54bfe..110e4994 100644
--- a/misc/hashset.ml
+++ b/misc/hashset.ml
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Mutable polymorphic hash-set} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type 'a t = ('a, unit) PHashtbl.t
   (** A set is a hashtable, with trivial values *)
 
@@ -49,11 +51,10 @@ let fold f acc set = PHashtbl.fold (fun acc x () -> f acc x) acc set
 
 let filter p set = PHashtbl.filter (fun x () -> p x) set 
 
-let to_seq set =
-  CCSequence.from_iter (fun k -> iter k set)
+let to_seq set k = iter k set
 
 let of_seq set seq =
-  CCSequence.iter (fun x -> add set x) seq
+  seq (fun x -> add set x)
 
 let union ?into (s1 : 'a t) (s2 : 'a t) =
   let into = match into with
@@ -62,10 +63,13 @@ let union ?into (s1 : 'a t) (s2 : 'a t) =
   of_seq into (to_seq s2);
   into
 
+let seq_filter p seq k =
+  seq (fun x -> if p x then k x)
+
 let inter ?into (s1 : 'a t) (s2 : 'a t) =
   let into = match into with
   | Some s -> s
   | None -> empty ~eq:s1.PHashtbl.eq ~hash:s1.PHashtbl.hash (cardinal s1) in
   (* add to [into] elements of [s1] that also belong to [s2] *)
-  of_seq into (CCSequence.filter (fun x -> mem s2 x) (to_seq s1));
+  of_seq into (seq_filter (fun x -> mem s2 x) (to_seq s1));
   into
diff --git a/misc/hashset.mli b/misc/hashset.mli
index 92af637f..f421c557 100644
--- a/misc/hashset.mli
+++ b/misc/hashset.mli
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Mutable polymorphic hash-set} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type 'a t = ('a, unit) PHashtbl.t
   (** A set is a hashtable, with trivial values *)
 
@@ -51,9 +53,9 @@ val fold : ('b -> 'a -> 'b) -> 'b -> 'a t -> 'b
 val filter : ('a -> bool) -> 'a t -> unit
   (** destructive filter (remove elements that do not satisfy the predicate) *)
 
-val to_seq : 'a t -> 'a CCSequence.t
+val to_seq : 'a t -> 'a sequence
 
-val of_seq : 'a t -> 'a CCSequence.t -> unit
+val of_seq : 'a t -> 'a sequence -> unit
 
 val union : ?into:'a t -> 'a t -> 'a t -> 'a t
   (** Set union. The result is stored in [into] *)
diff --git a/misc/heap.ml b/misc/heap.ml
index 1b7be900..7b402d51 100644
--- a/misc/heap.ml
+++ b/misc/heap.ml
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Imperative priority queue} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type 'a t = {
   mutable tree : 'a tree;
   cmp : 'a -> 'a -> int;
diff --git a/misc/heap.mli b/misc/heap.mli
index ba901f98..e9adee7c 100644
--- a/misc/heap.mli
+++ b/misc/heap.mli
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Imperative priority queue} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type 'a t
   (** A heap containing values of type 'a *)
 
@@ -51,6 +53,6 @@ val iter : 'a t -> ('a -> unit) -> unit
 
 val size : _ t -> int
 
-val to_seq : 'a t -> 'a CCSequence.t
+val to_seq : 'a t -> 'a sequence
 
-val of_seq : 'a t -> 'a CCSequence.t -> unit
+val of_seq : 'a t -> 'a sequence -> unit
diff --git a/misc/lazyGraph.ml b/misc/lazyGraph.ml
index 3a2f893a..6262096c 100644
--- a/misc/lazyGraph.ml
+++ b/misc/lazyGraph.ml
@@ -29,6 +29,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     a graph is always accessed from a given initial node (so only connected
     components can be represented by a single value of type ('v,'e) t). *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 (** {2 Type definitions} *)
 
 type ('id, 'v, 'e) t = {
@@ -41,7 +43,7 @@ type ('id, 'v, 'e) t = {
       other vertices, or to Empty if the identifier is not part of the graph. *)
 and ('id, 'v, 'e) node =
   | Empty
-  | Node of 'id * 'v * ('e * 'id) CCSequence.t
+  | Node of 'id * 'v * ('e * 'id) sequence
   (** A single node of the graph, with outgoing edges *)
 and ('id, 'e) path = ('id * 'e * 'id) list
   (** A reverse path (from the last element of the path to the first). *)
@@ -56,7 +58,7 @@ let empty =
 
 let singleton ?(eq=(=)) ?(hash=Hashtbl.hash) v label =
   let force v' =
-    if eq v v' then Node (v, label, CCSequence.empty) else Empty in
+    if eq v v' then Node (v, label, fun _ -> ()) else Empty in
   { force; eq; hash; }
 
 let make ?(eq=(=)) ?(hash=Hashtbl.hash) force =
@@ -66,7 +68,7 @@ let from_fun ?(eq=(=)) ?(hash=Hashtbl.hash) f =
   let force v =
     match f v with
     | None -> Empty
-    | Some (l, edges) -> Node (v, l, CCSequence.of_list edges) in
+    | Some (l, edges) -> Node (v, l, fun k -> List.iter k edges) in
   { eq; hash; force; }
 
 (** {2 Polymorphic map} *)
@@ -110,7 +112,7 @@ module Mutable = struct
     let map = mk_map ~eq ~hash in
     let force v =
       try let node = map.map_get v in
-          Node (v, node.mut_v, CCSequence.of_list node.mut_outgoing)
+          Node (v, node.mut_v, fun k -> List.iter k node.mut_outgoing)
       with Not_found -> Empty in
     let graph = { eq; hash; force; } in
     map, graph
@@ -129,12 +131,10 @@ end
 
 let from_enum ?(eq=(=)) ?(hash=Hashtbl.hash) ~vertices ~edges =
   let g, lazy_g = Mutable.create ~eq ~hash () in
-  CCSequence.iter
-    (fun (v,label_v) -> Mutable.add_vertex g v label_v;)
-    vertices;
-  CCSequence.iter
-    (fun (v1, e, v2) -> Mutable.add_edge g v1 e v2)
-    edges;
+  vertices
+    (fun (v,label_v) -> Mutable.add_vertex g v label_v;);
+  edges
+    (fun (v1, e, v2) -> Mutable.add_edge g v1 e v2);
   lazy_g
 
 let from_list ?(eq=(=)) ?(hash=Hashtbl.hash) l =
@@ -174,11 +174,11 @@ module Full = struct
     | [] -> false
 
   let bfs_full graph vertices =
-    CCSequence.from_iter (fun k ->
+    fun k ->
       let explored = mk_map ~eq:graph.eq ~hash:graph.hash in
       let id = ref 0 in
       let q = Queue.create () in (* queue of nodes to explore *)
-      CCSequence.iter (fun v -> Queue.push (FullEnter (v,[])) q) vertices;
+      vertices (fun v -> Queue.push (FullEnter (v,[])) q);
       while not (Queue.is_empty q) do
         match Queue.pop q with
         | FullEnter (v', path) ->
@@ -188,11 +188,11 @@ module Full = struct
             | Node (_, label, edges) ->
               explored.map_add v' ();
               (* explore neighbors *)
-              CCSequence.iter
+              edges
                 (fun (e,v'') ->
                   let path' = (v'',e,v') :: path in
-                  Queue.push (FullFollowEdge path') q)
-                edges;
+                  Queue.push (FullFollowEdge path') q
+                );
               (* exit node afterward *)
               Queue.push (FullExit v') q;
               (* return this vertex *)
@@ -213,17 +213,17 @@ module Full = struct
               Queue.push (FullEnter (v'', path')) q;
               k (MeetEdge (v'', e, v', EdgeForward))
             end
-      done)
+      done
 
   (* TODO: use a set of nodes currently being explored, rather than
     checking whether the node is in the path (should be faster) *)
 
   let dfs_full graph vertices =
-    CCSequence.from_iter (fun k ->
+    fun k ->
       let explored = mk_map ~eq:graph.eq ~hash:graph.hash in
       let id = ref 0 in
       let s = Stack.create () in (* stack of nodes to explore *)
-      CCSequence.iter (fun v -> Stack.push (FullEnter (v,[])) s) vertices;
+      vertices (fun v -> Stack.push (FullEnter (v,[])) s);
       while not (Stack.is_empty s) do
         match Stack.pop s with
         | FullExit v' -> k (ExitVertex v')
@@ -237,10 +237,10 @@ module Full = struct
               (* prepare to exit later *)
               Stack.push (FullExit v') s;
               (* explore neighbors *)
-              CCSequence.iter
+              edges
                 (fun (e,v'') ->
-                  Stack.push (FullFollowEdge ((v'', e, v') :: path)) s)
-                edges;
+                  Stack.push (FullFollowEdge ((v'', e, v') :: path)) s
+                );
               (* return this vertex *)
               let i = !id in
               incr id;
@@ -258,22 +258,28 @@ module Full = struct
               Stack.push (FullEnter (v'', path')) s;
               k (MeetEdge (v'', e, v', EdgeForward))
             end
-      done)
+      done
 end
 
+let seq_filter_map f seq k =
+  seq (fun x -> match f x with
+      | None -> ()
+      | Some y -> k y
+      )
+
 let bfs graph v =
-  CCSequence.fmap
+  seq_filter_map
     (function
       | Full.EnterVertex (v, l, i, _) -> Some (v, l, i)
       | _ -> None)
-    (Full.bfs_full graph (CCSequence.singleton v))
+    (Full.bfs_full graph (fun k -> k v))
 
 let dfs graph v =
-  CCSequence.fmap
+  seq_filter_map
     (function
       | Full.EnterVertex (v, l, i, _) -> Some (v, l, i)
       | _ -> None)
-    (Full.dfs_full graph (CCSequence.singleton v))
+    (Full.dfs_full graph (fun k -> k v))
 
 (** {3 Mutable heap} *)
 module Heap = struct
@@ -342,7 +348,7 @@ let a_star graph
   ?(distance=(fun v1 e v2 -> 1.))
   ~goal
   start =
-  CCSequence.from_iter (fun k ->
+  fun k ->
     (* map node -> 'came_from' cell *)
     let nodes = mk_map ~eq:graph.eq ~hash:graph.hash in
     (* priority queue for nodes to explore *)
@@ -376,7 +382,7 @@ let a_star graph
         | Empty -> ()
         | Node (_, label, edges) ->
           (* explore neighbors *)
-          CCSequence.iter
+          edges
             (fun (e,v'') ->
               let cost = dist +. distance v' e v'' +. heuristic v'' in
               let cell' =
@@ -395,14 +401,20 @@ let a_star graph
                   Heap.insert h (cost, v'');
                   cell'.cf_cost <- cost; (* update best cost/path *)
                   cell'.cf_prev <- CFEdge (e, cell);
-                end)
-            edges;
+                end);
           (* check whether the node we just explored is a goal node *)
           if goal v'
             (* found a goal node! yield it *)
             then k (dist, mk_path nodes [] v')
         end
-    done)
+    done
+
+exception ExitHead
+let seq_head seq =
+  let r = ref None in
+  try
+    seq (fun x -> r := Some x; raise ExitHead); None
+  with ExitHead -> !r
     
 (** Shortest path from the first node to the second one, according
     to the given (positive!) distance function. The path is reversed,
@@ -413,22 +425,29 @@ let dijkstra graph ?on_explore ?(ignore=fun v -> false)
     a_star graph ?on_explore ~ignore ~distance ~heuristic:(fun _ -> 0.)
        ~goal:(fun v -> graph.eq v v2) v1
   in
-  match CCSequence.to_list (CCSequence.take 1 paths) with
-  | [] -> raise Not_found
-  | [x] -> x
-  | _ -> assert false
+  match seq_head paths with
+  | None -> raise Not_found
+  | Some x -> x
+
+exception ExitForall
+let seq_for_all p seq =
+  try
+    seq (fun x -> if not (p x) then raise ExitForall);
+    true
+  with ExitForall -> false
+
 
 (** Is the subgraph explorable from the given vertex, a Directed
     Acyclic Graph? *)
 let is_dag graph v =
-  CCSequence.for_all
+  seq_for_all
     (function
       | Full.MeetEdge (_, _, _, Full.EdgeBackward) -> false
       | _ -> true)
-    (Full.dfs_full graph (CCSequence.singleton v))
+    (Full.dfs_full graph (fun k -> k v))
 
 let is_dag_full graph vs =
-  CCSequence.for_all
+  seq_for_all
     (function
       | Full.MeetEdge (_, _, _, Full.EdgeBackward) -> false
       | _ -> true)
@@ -443,9 +462,8 @@ let find_cycle graph v =
   let cycle = ref [] in
   try
     let path_stack = Stack.create () in
-    let seq = Full.dfs_full graph (CCSequence.singleton v) in
-    CCSequence.iter
-      (function
+    let seq = Full.dfs_full graph (fun k -> k v) in
+    seq (function
       | Full.EnterVertex (_, _, _, path) ->
         Stack.push path path_stack
       | Full.ExitVertex _ ->
@@ -456,8 +474,8 @@ let find_cycle graph v =
         let path = (v1, e, v2) :: path in
         cycle := path;
         raise Exit
-      | Full.MeetEdge _ -> ())
-      seq;
+      | Full.MeetEdge _ -> ()
+    );
     raise Not_found
   with Exit ->
     !cycle
@@ -471,6 +489,9 @@ let rev_path p =
 
 (** {2 Lazy transformations} *)
 
+let seq_map f seq k = seq (fun x -> k (f x))
+let seq_append s1 s2 k = s1 k; s2 k
+
 let union ?(combine=fun x y -> x) g1 g2 =
   let force v =
     match g1.force v, g2.force v with
@@ -478,7 +499,7 @@ let union ?(combine=fun x y -> x) g1 g2 =
     | ((Node _) as n), Empty -> n
     | Empty, ((Node _) as n) -> n
     | Node (_, l1, e1), Node (_, l2, e2) ->
-      Node (v, combine l1 l2, CCSequence.append e1 e2)
+      Node (v, combine l1 l2, seq_append e1 e2)
   in { eq=g1.eq; hash=g1.hash; force; }
 
 let map ~vertices ~edges g =
@@ -486,10 +507,12 @@ let map ~vertices ~edges g =
     match g.force v with
     | Empty -> Empty
     | Node (_, l, edges_enum) ->
-      let edges_enum' = CCSequence.map (fun (e,v') -> (edges e), v') edges_enum in
+      let edges_enum' = seq_map (fun (e,v') -> (edges e), v') edges_enum in
       Node (v, vertices l, edges_enum')
   in { eq=g.eq; hash=g.hash; force; }
 
+let seq_flat_map f seq k = seq (fun x -> f x k)
+
 (** Replace each vertex by some vertices. By mapping [v'] to [f v'=v1,...,vn],
     whenever [v] ---e---> [v'], then [v --e--> vi] for i=1,...,n. *)
 let flatMap f g =
@@ -497,24 +520,29 @@ let flatMap f g =
     match g.force v with
     | Empty -> Empty
     | Node (_, l, edges_enum) ->
-      let edges_enum' = CCSequence.flatMap
+      let edges_enum' = seq_flat_map
         (fun (e, v') ->
-          CCSequence.map (fun v'' -> e, v'') (f v'))
+          seq_map (fun v'' -> e, v'') (f v'))
         edges_enum in
       Node (v, l, edges_enum')
   in { eq=g.eq; hash=g.hash; force; }
 
+let seq_filter p seq k = seq (fun x -> if p x then k x)
+
 let filter ?(vertices=(fun v l -> true)) ?(edges=fun v1 e v2 -> true) g =
   let force v =
     match g.force v with
     | Empty -> Empty
     | Node (_, l, edges_enum) when vertices v l ->
       (* filter out edges *)
-      let edges_enum' = CCSequence.filter (fun (e,v') -> edges v e v') edges_enum in
+      let edges_enum' = seq_filter (fun (e,v') -> edges v e v') edges_enum in
       Node (v, l, edges_enum')
     | Node _ -> Empty  (* filter out this vertex *)
   in { eq=g.eq; hash=g.hash; force; }
 
+let seq_product s1 s2 k =
+  s1 (fun x -> s2 (fun y -> k(x,y)))
+
 let product g1 g2 =
   let force (v1,v2) =
     match g1.force v1, g2.force v2 with
@@ -522,8 +550,8 @@ let product g1 g2 =
     | _, Empty -> Empty
     | Node (_, l1, edges1), Node (_, l2, edges2) ->
       (* product of edges *)
-      let edges = CCSequence.product edges1 edges2 in
-      let edges = CCSequence.map (fun ((e1,v1'),(e2,v2')) -> ((e1,e2),(v1',v2'))) edges in
+      let edges = seq_product edges1 edges2 in
+      let edges = seq_map (fun ((e1,v1'),(e2,v2')) -> ((e1,e2),(v1',v2'))) edges in
       Node ((v1,v2), (l1,l2), edges)
   and eq (v1,v2) (v1',v2') =
     g1.eq v1 v1' && g2.eq v2 v2'
@@ -574,7 +602,7 @@ module Dot = struct
     (* print preamble *)
     Format.fprintf formatter "@[<v2>digraph %s {@;" name;
     (* traverse *)
-    CCSequence.iter
+    events
       (function
         | Full.EnterVertex (v, attrs, _, _) ->
           Format.fprintf formatter "  @[<h>%a %a;@]@." pp_vertex v
@@ -584,8 +612,8 @@ module Dot = struct
           Format.fprintf formatter "  @[<h>%a -> %a %a;@]@."
             pp_vertex v1 pp_vertex v2
             (CCList.print ~start:"[" ~stop:"]" ~sep:"," print_attribute)
-            attrs)
-      events;
+            attrs
+      );
     (* close *)
     Format.fprintf formatter "}@]@;@?";
     ()
@@ -608,17 +636,17 @@ let divisors_graph =
     if i > 2
       then
         let l = divisors [] 2 i in
-        let edges = CCSequence.map (fun i -> (), i) (CCSequence.of_list l) in
+        let edges = seq_map (fun i -> (), i) (fun k -> List.iter k l) in
         Node (i, i, edges)
       else
-        Node (i, i, CCSequence.empty)
+        Node (i, i, fun _ -> ())
   in make force
 
 let collatz_graph =
   let force i =
     if i mod 2 = 0
-      then Node (i, i, CCSequence.singleton ((), i / 2))
-      else Node (i, i, CCSequence.singleton ((), i * 3 + 1))
+      then Node (i, i, fun k -> k ((), i / 2))
+      else Node (i, i, fun k -> k ((), i * 3 + 1))
   in make force
 
 let collatz_graph_bis =
@@ -628,10 +656,10 @@ let collatz_graph_bis =
       ; false, i * 2 ] @
       if i mod 3 = 1 then [false, (i-1)/3] else []
     in
-    Node (i, i, CCSequence.of_list l)
+    Node (i, i, fun k -> List.iter k l)
   in make force
 
 let heap_graph =
   let force i =
-    Node (i, i, CCSequence.of_list [(), 2*i; (), 2*i+1])
+    Node (i, i, fun k -> List.iter k [(), 2*i; (), 2*i+1])
   in make force
diff --git a/misc/lazyGraph.mli b/misc/lazyGraph.mli
index 1b33d983..5c88d026 100644
--- a/misc/lazyGraph.mli
+++ b/misc/lazyGraph.mli
@@ -34,6 +34,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {2 Type definitions} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type ('id, 'v, 'e) t = {
   eq : 'id -> 'id -> bool;
   hash : 'id -> int;
@@ -44,7 +46,7 @@ type ('id, 'v, 'e) t = {
       other vertices, or to Empty if the identifier is not part of the graph. *)
 and ('id, 'v, 'e) node =
   | Empty
-  | Node of 'id * 'v * ('e * 'id) CCSequence.t
+  | Node of 'id * 'v * ('e * 'id) sequence
   (** A single node of the graph, with outgoing edges *)
 and ('id, 'e) path = ('id * 'e * 'id) list
   (** A reverse path (from the last element of the path to the first). *)
@@ -70,8 +72,8 @@ val make : ?eq:('id -> 'id -> bool) -> ?hash:('id -> int) ->
   (** Build a graph from the [force] function *)
 
 val from_enum : ?eq:('id -> 'id -> bool) -> ?hash:('id -> int) ->
-                vertices:('id * 'v) CCSequence.t ->
-                edges:('id * 'e * 'id) CCSequence.t ->
+                vertices:('id * 'v) sequence ->
+                edges:('id * 'e * 'id) sequence ->
                 ('id, 'v, 'e) t
   (** Concrete (eager) representation of a Graph *)
 
@@ -117,21 +119,21 @@ module Full : sig
     | EdgeBackward    (* toward the current trail *)
     | EdgeTransverse  (* toward a totally explored part of the graph *)
 
-  val bfs_full : ('id, 'v, 'e) t -> 'id CCSequence.t ->
-                  ('id, 'v, 'e) traverse_event CCSequence.t
+  val bfs_full : ('id, 'v, 'e) t -> 'id sequence ->
+                  ('id, 'v, 'e) traverse_event sequence
     (** Lazy traversal in breadth first from a finite set of vertices *)
 
-  val dfs_full : ('id, 'v, 'e) t -> 'id CCSequence.t ->
-                 ('id, 'v, 'e) traverse_event CCSequence.t
+  val dfs_full : ('id, 'v, 'e) t -> 'id sequence ->
+                 ('id, 'v, 'e) traverse_event sequence
     (** Lazy traversal in depth first from a finite set of vertices *)
 end
 
 (** The traversal functions assign a unique ID to every traversed node *)
 
-val bfs : ('id, 'v, 'e) t -> 'id -> ('id * 'v * int) CCSequence.t
+val bfs : ('id, 'v, 'e) t -> 'id -> ('id * 'v * int) sequence
   (** Lazy traversal in breadth first *)
 
-val dfs : ('id, 'v, 'e) t -> 'id -> ('id * 'v * int) CCSequence.t
+val dfs : ('id, 'v, 'e) t -> 'id -> ('id * 'v * int) sequence
   (** Lazy traversal in depth first *)
 
 module Heap : sig
@@ -149,7 +151,7 @@ val a_star : ('id, 'v, 'e) t ->
              ?distance:('id -> 'e -> 'id -> float) ->
              goal:('id -> bool) ->
              'id ->
-             (float * ('id, 'e) path) CCSequence.t
+             (float * ('id, 'e) path) sequence
   (** Shortest path from the first node to nodes that satisfy [goal], according
       to the given (positive!) distance function. The distance is also returned.
       [ignore] allows one to ignore some vertices during exploration.
@@ -174,7 +176,7 @@ val is_dag : ('id, _, _) t -> 'id -> bool
   (** Is the subgraph explorable from the given vertex, a Directed
       Acyclic Graph? *)
 
-val is_dag_full : ('id, _, _) t -> 'id CCSequence.t -> bool
+val is_dag_full : ('id, _, _) t -> 'id sequence -> bool
   (** Is the Graph reachable from the given vertices, a DAG? See {! is_dag} *)
 
 val find_cycle : ('id, _, 'e) t -> 'id -> ('id, 'e) path
@@ -196,7 +198,7 @@ val map : vertices:('v -> 'v2) -> edges:('e -> 'e2) ->
           ('id, 'v, 'e) t -> ('id, 'v2, 'e2) t
   (** Map vertice and edge labels *)
 
-val flatMap : ('id -> 'id CCSequence.t) ->
+val flatMap : ('id -> 'id sequence) ->
               ('id, 'v, 'e) t ->
               ('id, 'v, 'e) t
   (** Replace each vertex by some vertices. By mapping [v'] to [f v'=v1,...,vn],
@@ -231,12 +233,12 @@ module Dot : sig
 
   val pp_enum : ?eq:('id -> 'id -> bool) -> ?hash:('id -> int) ->
                 name:string -> Format.formatter ->
-                ('id,attribute list,attribute list) Full.traverse_event CCSequence.t ->
+                ('id,attribute list,attribute list) Full.traverse_event sequence ->
                 unit
 
   val pp : name:string -> ('id, attribute list, attribute list) t ->
            Format.formatter ->
-           'id CCSequence.t -> unit
+           'id sequence -> unit
     (** Pretty print the given graph (starting from the given set of vertices)
         to the channel in DOT format *)
 end
diff --git a/misc/pHashtbl.ml b/misc/pHashtbl.ml
index fc138ecf..86458bcf 100644
--- a/misc/pHashtbl.ml
+++ b/misc/pHashtbl.ml
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Open addressing hashtable (robin hood hashing)} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type ('a, 'b) t = {
   mutable buckets : ('a, 'b) bucket array;
   mutable size : int;
@@ -77,7 +79,7 @@ let clear t =
 (** Index of slot, for i-th probing starting from hash [h] in
     a table of length [n] *)
 let addr h n i = (h + i) mod n
-  
+
 (** Insert (key -> value) in table, starting with the hash. *)
 let insert t key value =
   let n = Array.length t.buckets in
@@ -217,12 +219,10 @@ let filter pred t =
 
 (** Add the given pairs to the hashtable *)
 let of_seq t seq =
-  CCSequence.iter (fun (k,v) -> add t k v) seq
+  seq (fun (k,v) -> add t k v)
 
 (** CCSequence of pairs *)
-let to_seq t =
-  CCSequence.from_iter
-    (fun kont -> iter (fun k v -> kont (k,v)) t)
+let to_seq t kont = iter (fun k v -> kont (k,v)) t
 
 (** Statistics on the table *)
 let stats t = (Array.length t.buckets, t.size, t.size, 0, 0, 1)
diff --git a/misc/pHashtbl.mli b/misc/pHashtbl.mli
index d5d8bd54..2a9c82c1 100644
--- a/misc/pHashtbl.mli
+++ b/misc/pHashtbl.mli
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Open addressing hashtable (robin hood hashing)} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type ('a, 'b) t = {
   mutable buckets : ('a, 'b) bucket array;
   mutable size : int;
@@ -90,11 +92,11 @@ val filter : ('a -> 'b -> bool) -> ('a, 'b) t -> unit
 val fold : ('c -> 'a -> 'b -> 'c) -> 'c -> ('a, 'b) t -> 'c
   (** Fold on bindings *)
 
-val of_seq : ('a, 'b) t -> ('a * 'b) CCSequence.t -> unit
+val of_seq : ('a, 'b) t -> ('a * 'b) sequence -> unit
   (** Add the given pairs to the hashtable *)
 
-val to_seq : ('a, 'b) t -> ('a * 'b) CCSequence.t
-  (** CCSequence of pairs *)
+val to_seq : ('a, 'b) t -> ('a * 'b) sequence
+  (** Sequence of pairs *)
 
 val stats : (_, _) t -> int * int * int * int * int * int
   (** Cf Weak.S *)
diff --git a/misc/parseReact.ml b/misc/parseReact.ml
index d1eee788..99b7c12e 100644
--- a/misc/parseReact.ml
+++ b/misc/parseReact.ml
@@ -232,6 +232,6 @@ let run p seq =
     <|> (skip_spaces >> exact '(' >> many1 ~sep:(exact ' ') (delay p) >>= fun l ->
         skip_spaces >> exact ')' >> return (list_ l))
   in
-  let res = run (p ()) (CCSequence.of_str "(a b (c d))") in
+  let res = run (p ()) (Sequence.of_str "(a b (c d))") in
   assert_equal res [list_ [atom "a"; atom "b"; list_ [atom "c"; atom "d"]]]
 *)
diff --git a/misc/persistentGraph.ml b/misc/persistentGraph.ml
index 1928e6f5..fb42ea08 100644
--- a/misc/persistentGraph.ml
+++ b/misc/persistentGraph.ml
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 A simple polymorphic directed graph.} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type ('v, 'e) t = ('v, ('v, 'e) node) PHashtbl.t
   (** Graph parametrized by a type for vertices, and one for edges *)
 and ('v, 'e) node = {
@@ -83,25 +85,27 @@ let add t v1 e v2 =
   ()
 
 let add_seq t seq =
-  CCSequence.iter (fun (v1,e,v2) -> add t v1 e v2) seq
+  seq (fun (v1,e,v2) -> add t v1 e v2)
 
-let next t v =
-  CCSequence.of_list (PHashtbl.find t v).n_next
+let next t v k =
+  List.iter k  (PHashtbl.find t v).n_next
 
-let prev t v =
-  CCSequence.of_list (PHashtbl.find t v).n_prev
+let prev t v k =
+  List.iter k (PHashtbl.find t v).n_prev
+
+let seq_map f seq k = seq (fun x -> k (f x))
+let seq_filter p seq k = seq (fun x -> if p x then k x)
 
 let between t v1 v2 =
-  let edges = CCSequence.of_list (PHashtbl.find t v1).n_next in
-  let edges = CCSequence.filter (fun (e, v2') -> (PHashtbl.get_eq t) v2 v2') edges in
-  CCSequence.map fst edges
+  let edges k = List.iter k (PHashtbl.find t v1).n_next in
+  let edges = seq_filter (fun (e, v2') -> (PHashtbl.get_eq t) v2 v2') edges in
+  seq_map fst edges
 
 (** Call [k] on every vertex *)
 let iter_vertices t k =
   PHashtbl.iter (fun v _ -> k v) t
 
-let vertices t =
-  CCSequence.from_iter (iter_vertices t)
+let vertices t = iter_vertices t
 
 (** Call [k] on every edge *)
 let iter t k =
@@ -109,27 +113,37 @@ let iter t k =
     (fun v1 node -> List.iter (fun (e, v2) -> k (v1, e, v2)) node.n_next)
     t
 
-let to_seq t =
-  CCSequence.from_iter (iter t)
+let to_seq t = iter t
 
 (** {2 Global operations} *)
 
+exception ExitIsEmpty
+let seq_is_empty seq =
+  try seq (fun _ -> raise ExitIsEmpty); true
+  with ExitIsEmpty -> false
+
 (** Roots, ie vertices with no incoming edges *)
 let roots g =
   let vertices = vertices g in
-  CCSequence.filter (fun v -> CCSequence.is_empty (prev g v)) vertices
+  seq_filter (fun v -> seq_is_empty (prev g v)) vertices
 
 (** Leaves, ie vertices with no outgoing edges *)
 let leaves g =
   let vertices = vertices g in
-  CCSequence.filter (fun v -> CCSequence.is_empty (next g v)) vertices
+  seq_filter (fun v -> seq_is_empty (next g v)) vertices
+
+exception ExitHead
+let seq_head seq =
+  let r = ref None in
+  try
+    seq (fun x -> r := Some x; raise ExitHead); None
+  with ExitHead -> !r
 
 (** Pick a vertex, or raise Not_found *)
 let choose g =
-  match CCSequence.to_list (CCSequence.take 1 (vertices g)) with
-  | [x] -> x
-  | [] -> raise Not_found
-  | _ -> assert false
+  match seq_head (vertices g) with
+  | Some x -> x
+  | None -> raise Not_found
 
 let rev_edge (v,e,v') = (v',e,v)
 
@@ -155,14 +169,12 @@ let bfs graph first k =
     (* yield current node *)
     k v;
     (* explore children *)
-    CCSequence.iter
+    next graph v 
       (fun (e, v') -> if not (Hashset.mem explored v')
         then (Hashset.add explored v'; Queue.push v' q))
-      (next graph v)
   done
 
-let bfs_seq graph first =
-  CCSequence.from_iter (fun k -> bfs graph first k)
+let bfs_seq graph first k = bfs graph first k
 
 (** DFS, with callbacks called on each encountered node and edge *)
 let dfs_full graph ?(labels=mk_v_table graph)
@@ -183,7 +195,7 @@ first
       (* enter the node *)
       enter trail';
       (* explore edges *)
-      CCSequence.iter
+      next graph v
         (fun (e, v') ->
           try let n' = PHashtbl.find labels v' in
               if n' < n && List.exists (fun (_,n'') -> n' = n'') trail'
@@ -192,8 +204,8 @@ first
                 fwd_edge (v,e,v')   (* forward or cross edge *)
           with Not_found ->
             tree_edge (v,e,v'); (* tree edge *)
-            explore trail' v')  (* explore the subnode *)
-        (next graph v);
+            explore trail' v'  (* explore the subnode *)
+        );
       (* exit the node *)
       exit trail'
     end
@@ -216,10 +228,10 @@ let is_dag g =
   else try
     let labels = mk_v_table g in
     (* do a DFS from each root; any back edge indicates a cycle *)
-    CCSequence.iter
+    vertices g
       (fun v ->
-        dfs_full g ~labels ~back_edge:(fun _ -> raise Exit) v)
-      (vertices g);
+        dfs_full g ~labels ~back_edge:(fun _ -> raise Exit) v
+      );
     true   (* complete traversal without back edge *)
   with Exit ->
     false  (* back edge detected! *)
@@ -259,14 +271,13 @@ let min_path_full (type v) (type e) graph
       else begin
         Hashset.add explored v;
         (* explore successors *)
-        CCSequence.iter
+        next graph v
           (fun (e, v') ->
             if Hashset.mem explored v' || ignore v' then ()
             else
               let cost_v' = (cost v e v') + cost_v in
               let path' = (v',e,v) :: path in
               Heap.insert q (v', cost_v', path'))
-          (next graph v)
       end
     done;
     (* if a satisfying path was found, Exit would have been raised *)
@@ -307,7 +318,7 @@ type attribute = [
 
 (** Pretty print the graph in DOT, on given formatter. Using a sequence
     allows to easily select which edges are important,
-    or to combine several graphs with [CCSequence.append]. *)
+    or to combine several graphs with [seq_append]. *)
 let pp ~name ?vertices
 ~(print_edge : 'v -> 'e -> 'v -> attribute list)
 ~(print_vertex : 'v -> attribute list) formatter (graph : ('v, 'e) t) =
@@ -341,14 +352,14 @@ let pp ~name ?vertices
   (* print preamble *)
   Format.fprintf formatter "@[<v2>digraph %s {@;" name;
   (* print edges *)
-  CCSequence.iter
+  to_seq graph
     (fun (v1, e, v2) ->
       let attributes = print_edge v1 e v2 in
       Format.fprintf formatter "  @[<h>%a -> %a [%a];@]@."
         pp_vertex v1 pp_vertex v2
         (CCList.print ~sep:"," print_attribute)
-        attributes)
-    (to_seq graph);
+        attributes
+    );
   (* print vertices *)
   PHashtbl.iter
     (fun v _ ->
diff --git a/misc/persistentGraph.mli b/misc/persistentGraph.mli
index 6c061706..8ec044cc 100644
--- a/misc/persistentGraph.mli
+++ b/misc/persistentGraph.mli
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 A simple polymorphic directed graph.} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 (** {2 Basics} *)
 
 type ('v, 'e) t
@@ -51,31 +53,31 @@ val length : (_, _) t -> int
 val add : ('v,'e) t -> 'v -> 'e -> 'v -> unit
   (** Add an edge between two vertices *)
 
-val add_seq : ('v,'e) t -> ('v * 'e * 'v) CCSequence.t -> unit
+val add_seq : ('v,'e) t -> ('v * 'e * 'v) sequence -> unit
   (** Add the vertices to the graph *)
 
-val next : ('v, 'e) t -> 'v -> ('e * 'v) CCSequence.t
+val next : ('v, 'e) t -> 'v -> ('e * 'v) sequence
   (** Outgoing edges *)
 
-val prev : ('v, 'e) t -> 'v -> ('e * 'v) CCSequence.t
+val prev : ('v, 'e) t -> 'v -> ('e * 'v) sequence
   (** Incoming edges *)
 
-val between : ('v, 'e) t -> 'v -> 'v -> 'e CCSequence.t
+val between : ('v, 'e) t -> 'v -> 'v -> 'e sequence
 
 val iter_vertices : ('v, 'e) t -> ('v -> unit) -> unit
-val vertices : ('v, 'e) t -> 'v CCSequence.t
+val vertices : ('v, 'e) t -> 'v sequence
     (** Iterate on vertices *)
 
 val iter : ('v, 'e) t -> ('v * 'e * 'v -> unit) -> unit 
-val to_seq : ('v, 'e) t -> ('v * 'e * 'v) CCSequence.t
+val to_seq : ('v, 'e) t -> ('v * 'e * 'v) sequence
   (** Dump the graph as a sequence of vertices *)
 
 (** {2 Global operations} *)
 
-val roots : ('v, 'e) t -> 'v CCSequence.t
+val roots : ('v, 'e) t -> 'v sequence
   (** Roots, ie vertices with no incoming edges *)
 
-val leaves : ('v, 'e) t -> 'v CCSequence.t
+val leaves : ('v, 'e) t -> 'v sequence
   (** Leaves, ie vertices with no outgoing edges *)
 
 val choose : ('v, 'e) t -> 'v
@@ -92,8 +94,8 @@ val rev : ('v, 'e) t -> unit
 val bfs : ('v, 'e) t -> 'v -> ('v -> unit) -> unit
   (** Breadth-first search, from given 'v *)
 
-val bfs_seq : ('v, 'e) t -> 'v -> 'v CCSequence.t
-  (** CCSequence of vertices traversed during breadth-first search *)
+val bfs_seq : ('v, 'e) t -> 'v -> 'v sequence
+  (** Sequence of vertices traversed during breadth-first search *)
 
 val dfs_full : ('v, 'e) t ->
                ?labels:('v, int) PHashtbl.t ->
diff --git a/misc/skipList.ml b/misc/skipList.ml
index 60db79a6..c9af6a63 100644
--- a/misc/skipList.ml
+++ b/misc/skipList.ml
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Imperative skip-list} *)
 
+type 'a gen = unit -> 'a option
+
 (** Most functions are inspired from
     "A skip list cookbook", William Pugh, 1989. *)
 
@@ -187,6 +189,10 @@ let gen l =
       x := a.(0);
       Some (k, !v)
 
+let rec gen_iter f g = match g() with
+  | None -> ()
+  | Some x -> f x; gen_iter f g
+
 (** Add content of the iterator to the list *)
 let of_gen l gen =
-  CCGen.iter (fun (k,v) -> add l k v) gen
+  gen_iter (fun (k,v) -> add l k v) gen
diff --git a/misc/skipList.mli b/misc/skipList.mli
index 42b357c9..d701e4b9 100644
--- a/misc/skipList.mli
+++ b/misc/skipList.mli
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Imperative skip-list} *)
 
+type 'a gen = unit -> 'a option
+
 type ('a, 'b) t
   (** A skip list that maps elements of type 'a to elements of type 'b *)
 
@@ -53,6 +55,6 @@ val remove : ('a, 'b) t -> 'a -> unit
 val length : (_, _) t -> int
   (** Number of elements *)
 
-val gen : ('a, 'b) t -> ('a * 'b) CCGen.t
+val gen : ('a, 'b) t -> ('a * 'b) gen
 
-val of_gen : ('a, 'b) t -> ('a * 'b) CCGen.t -> unit
+val of_gen : ('a, 'b) t -> ('a * 'b) gen -> unit
diff --git a/misc/smallSet.ml b/misc/smallSet.ml
index 24b5ae69..23082bfa 100644
--- a/misc/smallSet.ml
+++ b/misc/smallSet.ml
@@ -25,6 +25,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Small set structure} *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 type 'a t = {
   cmp : 'a -> 'a -> int;
   nodes : 'a node;
@@ -123,11 +125,15 @@ let to_seq set =
     iter k set
 
 let of_seq set seq =
-  CCSequence.fold add set seq
+  let set = ref set in
+  seq (fun x -> set := add !set x);
+  !set
 
 let to_list set =
-  CCSequence.to_rev_list (to_seq set)
+  let l = ref [] in
+  to_seq set (fun x -> l := x :: !l);
+  !l
 
 let of_list set l =
-  of_seq set (CCSequence.of_list l)
+  List.fold_left add set l
 
diff --git a/misc/smallSet.mli b/misc/smallSet.mli
index 1582b5e8..0a46593e 100644
--- a/misc/smallSet.mli
+++ b/misc/smallSet.mli
@@ -29,6 +29,9 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     function. It is implemented as a sorted list, so most operations
     are in linear time. *)
 
+type 'a sequence = ('a -> unit) -> unit
+
+
 type 'a t
   (** Set of elements of type 'a *)
 
@@ -59,9 +62,9 @@ val iter : ('a -> unit) -> 'a t -> unit
 val size : _ t -> int
   (** Number of elements *)
 
-val to_seq : 'a t -> 'a CCSequence.t
+val to_seq : 'a t -> 'a sequence
 
-val of_seq : 'a t -> 'a CCSequence.t -> 'a t
+val of_seq : 'a t -> 'a sequence -> 'a t
 
 val to_list : 'a t -> 'a list
 
diff --git a/misc/splayMap.ml b/misc/splayMap.ml
index 5e6465f9..4a9de67d 100644
--- a/misc/splayMap.ml
+++ b/misc/splayMap.ml
@@ -29,6 +29,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 http://www.cs.cornell.edu/Courses/cs3110/2009fa/recitations/rec-splay.html
 *)
 
+type 'a sequence = ('a -> unit) -> unit
+
 (** {2 Polymorphic Maps} *)
 
 type ('a, 'b) t = {
@@ -192,11 +194,12 @@ let choose t =
   | Node (k, v, _, _) -> k, v
 
 let to_seq t =
-  CCSequence.from_iter
-    (fun kont -> iter t (fun k v -> kont (k, v)))
+  fun kont -> iter t (fun k v -> kont (k, v))
 
 let of_seq t seq =
-  CCSequence.fold (fun t (k, v) -> add t k v) t seq
+  let t = ref t in
+  seq (fun (k, v) -> t := add !t k v);
+  !t
 
 (** {2 Functorial interface} *)
 
@@ -238,9 +241,9 @@ module type S = sig
   val choose : 'a t -> (key * 'a)
     (** Some binding, or raises Not_found *)
 
-  val to_seq : 'a t -> (key * 'a) CCSequence.t
+  val to_seq : 'a t -> (key * 'a) sequence
 
-  val of_seq : 'a t -> (key * 'a) CCSequence.t -> 'a t
+  val of_seq : 'a t -> (key * 'a) sequence -> 'a t
 end
 
 module type ORDERED = sig
@@ -404,9 +407,10 @@ module Make(X : ORDERED) = struct
     | Node (k, v, _, _) -> k, v
 
   let to_seq t =
-    CCSequence.from_iter
-      (fun kont -> iter t (fun k v -> kont (k, v)))
+    fun kont -> iter t (fun k v -> kont (k, v))
 
   let of_seq t seq =
-    CCSequence.fold (fun t (k, v) -> add t k v) t seq
+    let t = ref t in
+    seq (fun (k, v) -> t := add !t k v);
+    !t
 end
diff --git a/misc/splayMap.mli b/misc/splayMap.mli
index 8d591977..6733f506 100644
--- a/misc/splayMap.mli
+++ b/misc/splayMap.mli
@@ -28,6 +28,9 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 (* TODO: map-wide operations: merge, compare, equal, for_all, exists,
         batch (sorted) add, partition, split, max_elt, min_elt, map... *)
 
+type 'a sequence = ('a -> unit) -> unit
+
+
 (** {2 Polymorphic Maps} *)
 
 type ('a, 'b) t
@@ -69,9 +72,9 @@ val size : (_, _) t -> int
 val choose : ('a, 'b) t -> ('a * 'b)
   (** Some binding, or raises Not_found *)
 
-val to_seq : ('a, 'b) t -> ('a * 'b) CCSequence.t
+val to_seq : ('a, 'b) t -> ('a * 'b) sequence
 
-val of_seq : ('a, 'b) t -> ('a * 'b) CCSequence.t -> ('a, 'b) t
+val of_seq : ('a, 'b) t -> ('a * 'b) sequence -> ('a, 'b) t
 
 (** {2 Functorial interface} *)
 
@@ -113,9 +116,9 @@ module type S = sig
   val choose : 'a t -> (key * 'a)
     (** Some binding, or raises Not_found *)
 
-  val to_seq : 'a t -> (key * 'a) CCSequence.t
+  val to_seq : 'a t -> (key * 'a) sequence
 
-  val of_seq : 'a t -> (key * 'a) CCSequence.t -> 'a t
+  val of_seq : 'a t -> (key * 'a) sequence -> 'a t
 end
 
 module type ORDERED = sig
diff --git a/tests/run_tests.ml b/tests/run_tests.ml
index cf4787ac..2641584d 100644
--- a/tests/run_tests.ml
+++ b/tests/run_tests.ml
@@ -13,7 +13,6 @@ let suite =
       Test_cc.suite;
       Test_puf.suite;
       Test_vector.suite;
-      Test_gen.suite;
       Test_deque.suite;
       Test_fHashtbl.suite;
       Test_fQueue.suite;
diff --git a/tests/test_CCHeap.ml b/tests/test_CCHeap.ml
index a0c97a79..3b4547a3 100644
--- a/tests/test_CCHeap.ml
+++ b/tests/test_CCHeap.ml
@@ -3,8 +3,6 @@
 
 open OUnit
 
-module Sequence = CCSequence
-
 module H = CCHeap.Make(struct type t = int let leq x y =x<=y end)
 
 let empty = H.empty
diff --git a/tests/test_PersistentHashtbl.ml b/tests/test_PersistentHashtbl.ml
index 8d466484..dd84be8a 100644
--- a/tests/test_PersistentHashtbl.ml
+++ b/tests/test_PersistentHashtbl.ml
@@ -2,7 +2,6 @@
 open OUnit
 
 module H = CCPersistentHashtbl.Make(CCInt)
-module Sequence = CCSequence
 
 let test_add () =
   let h = H.create 32 in
diff --git a/tests/test_bv.ml b/tests/test_bv.ml
index d6909679..2a7a6152 100644
--- a/tests/test_bv.ml
+++ b/tests/test_bv.ml
@@ -1,6 +1,6 @@
 open OUnit
 
-module Sequence = CCSequence
+
 
 let test_cardinal () =
   let bv1 = CCBV.create ~size:87 true in
diff --git a/tests/test_deque.ml b/tests/test_deque.ml
index aecd15d1..76a5448a 100644
--- a/tests/test_deque.ml
+++ b/tests/test_deque.ml
@@ -2,7 +2,7 @@
 open OUnit
 
 module Deque = CCDeque
-module Sequence = CCSequence
+
 
 let plist l = CCPrint.to_string (CCList.pp CCInt.pp) l 
 let pint i = string_of_int i
diff --git a/tests/test_fHashtbl.ml b/tests/test_fHashtbl.ml
index 1c81e37e..d77d7b13 100644
--- a/tests/test_fHashtbl.ml
+++ b/tests/test_fHashtbl.ml
@@ -2,7 +2,7 @@
 open OUnit
 open Containers_misc
 
-module Sequence = CCSequence
+
 
 module Test(SomeHashtbl : FHashtbl.S with type key = int) = struct
   let test_add () =
diff --git a/tests/test_fQueue.ml b/tests/test_fQueue.ml
index 33082e5e..7388d551 100644
--- a/tests/test_fQueue.ml
+++ b/tests/test_fQueue.ml
@@ -2,7 +2,7 @@
 open OUnit
 
 module FQueue = CCFQueue
-module Sequence = CCSequence
+
 
 let test_empty () =
   let q = FQueue.empty in
diff --git a/tests/test_flatHashtbl.ml b/tests/test_flatHashtbl.ml
index 60437386..d0cde3a9 100644
--- a/tests/test_flatHashtbl.ml
+++ b/tests/test_flatHashtbl.ml
@@ -2,7 +2,7 @@
 open OUnit
 open Containers_misc
 
-module Sequence = CCSequence
+
 
 module IHashtbl = FlatHashtbl.Make(struct
   type t = int
diff --git a/tests/test_gen.ml b/tests/test_gen.ml
deleted file mode 100644
index 17596130..00000000
--- a/tests/test_gen.ml
+++ /dev/null
@@ -1,132 +0,0 @@
-
-open OUnit
-open CCFun
-
-module Gen = CCGen
-module GR = Gen.Restart
-
-let pint i = string_of_int i
-let plist l =
-  CCPrint.to_string (CCList.pp CCInt.pp) l
-let pstrlist l =
-  CCPrint.to_string (CCList.pp Buffer.add_string) l
-
-let test_singleton () =
-  let gen = Gen.singleton 42 in
-  OUnit.assert_equal (Some 42) (Gen.get gen);
-  OUnit.assert_equal None (Gen.get gen);
-  let gen = Gen.singleton 42 in
-  OUnit.assert_equal 1 (Gen.length gen);
-  ()
-
-let test_iter () =
-  let e = GR.(1 -- 10) in
-  OUnit.assert_equal ~printer:pint 10 (GR.length e);
-  OUnit.assert_equal [1;2] GR.(to_list (1 -- 2));
-  OUnit.assert_equal [1;2;3;4;5] (GR.to_list (GR.take 5 e));
-  ()
-
-let test_map () =
-  let e = Gen.(1 -- 10) in
-  let e' = Gen.map string_of_int e in
-  OUnit.assert_equal ~printer:pstrlist ["9"; "10"] (Gen.to_list (Gen.drop 8 e'));
-  ()
-
-let test_append () =
-  let e = Gen.append Gen.(1 -- 5) Gen.(6 -- 10) in
-  OUnit.assert_equal [10;9;8;7;6;5;4;3;2;1] (Gen.to_rev_list e);
-  ()
-
-let test_flatMap () =
-  let e = Gen.(1 -- 3) in
-  let e' = Gen.(e >>= (fun x -> x -- (x+1))) in
-  OUnit.assert_equal [1;2;2;3;3;4] (Gen.to_list e');
-  ()
-
-let test_zip () =
-  let e = Gen.zip_with (+) (Gen.repeat 1) Gen.(4--7) in
-  OUnit.assert_equal [5;6;7;8] (Gen.to_list e);
-  ()
-
-let test_filterMap () =
-  let f x = if x mod 2 = 0 then Some (string_of_int x) else None in
-  let e = Gen.filter_map f Gen.(1 -- 10) in
-  OUnit.assert_equal ["2"; "4"; "6"; "8"; "10"] (Gen.to_list e);
-  ()
-
-let test_merge () =
-  let e = Gen.of_list [Gen.(1--3); Gen.(4--6); Gen.(7--9)] in
-  let e' = Gen.merge e in
-  OUnit.assert_equal [1;2;3;4;5;6;7;8;9] (Gen.to_list e' |> List.sort compare);
-  ()
-
-let test_persistent () =
-  let i = ref 0 in
-  let gen () =
-    let j = !i in
-    if j > 5 then None else (incr i; Some j)
-  in
-  let e = Gen.persistent gen in
-  OUnit.assert_equal [0;1;2;3;4;5] (GR.to_list e);
-  OUnit.assert_equal [0;1;2;3;4;5] (GR.to_list e);
-  OUnit.assert_equal [0;1;2;3;4;5] (GR.to_list e);
-  ()
-
-let test_round_robin () =
-  let e = GR.round_robin ~n:2 GR.(1--10) in
-  match e with
-  | [a;b] ->
-    OUnit.assert_equal [1;3;5;7;9] (Gen.to_list a);
-    OUnit.assert_equal [2;4;6;8;10] (Gen.to_list b)
-  | _ -> OUnit.assert_failure "wrong list lenght"
-
-let test_big_rr () =
-  let e = GR.round_robin ~n:3 GR.(1 -- 999) in
-  let l = List.map Gen.length e in
-  OUnit.assert_equal [333;333;333] l;
-  ()
-
-let test_merge_sorted () =
-  [Gen.of_list [1;3;5]; Gen.of_list [0;1;1;3;4;6;10]; Gen.of_list [2;2;11]]
-    |> Gen.sorted_merge_n ?cmp:None
-    |> Gen.to_list
-    |> OUnit.assert_equal ~printer:Helpers.print_int_list [0;1;1;1;2;2;3;3;4;5;6;10;11]
-
-let test_interleave () =
-  let e1 = Gen.of_list [1;3;5;7;9] in
-  let e2 = Gen.of_list [2;4;6;8;10] in
-  let e = Gen.interleave e1 e2 in
-  OUnit.assert_equal [1;2;3;4;5;6;7;8;9;10] (Gen.to_list e);
-  ()
-
-let test_intersperse () =
-  let e = Gen.(1 -- 5) in
-  let e' = Gen.intersperse 0 e in
-  OUnit.assert_equal [1;0;2;0;3;0;4;0;5] (Gen.to_list e');
-  ()
-
-let test_product () =
-  let printer = Helpers.print_int_int_list in
-  let e = Gen.product Gen.(1--3) Gen.(4--5) in
-  OUnit.assert_equal ~printer [1,4; 1,5; 2,4; 2,5; 3,4; 3,5]
-    (List.sort compare (Gen.to_list e));
-  ()
-
-let suite =
-  "test_gen" >:::
-    [ "test_singleton" >:: test_singleton;
-      "test_iter" >:: test_iter;
-      "test_map" >:: test_map;
-      "test_append" >:: test_append;
-      "test_flatMap" >:: test_flatMap;
-      "test_zip" >:: test_zip;
-      "test_filterMap" >:: test_filterMap;
-      "test_merge" >:: test_merge;
-      "test_persistent" >:: test_persistent;
-      "test_round_robin" >:: test_round_robin;
-      "test_big_rr" >:: test_big_rr;
-      "test_merge_sorted" >:: test_merge_sorted;
-      "test_interleave" >:: test_interleave;
-      "test_intersperse" >:: test_intersperse;
-      "test_product" >:: test_product;
-    ]
diff --git a/tests/test_graph.ml b/tests/test_graph.ml
index a18913a7..70e126d3 100644
--- a/tests/test_graph.ml
+++ b/tests/test_graph.ml
@@ -5,7 +5,7 @@ open OUnit
 open Helpers
 open Containers_misc
 
-module Sequence = CCSequence
+
 module G = PersistentGraph
 
 (* build a graph from a list of pairs of ints *)
diff --git a/tests/test_heap.ml b/tests/test_heap.ml
index c4162e23..62b62586 100644
--- a/tests/test_heap.ml
+++ b/tests/test_heap.ml
@@ -3,7 +3,7 @@
 open OUnit
 open Helpers
 open Containers_misc
-module Sequence = CCSequence
+
 
 let test_empty () =
   let h = Heap.empty ~cmp:(fun x y -> x - y) in
diff --git a/tests/test_mixtbl.ml b/tests/test_mixtbl.ml
index f58fc2bb..f3e8c320 100644
--- a/tests/test_mixtbl.ml
+++ b/tests/test_mixtbl.ml
@@ -66,7 +66,7 @@ let test_keys () =
   Mixtbl.set ~inj:inj_int tbl "foo" 1;
   Mixtbl.set ~inj:inj_int tbl "bar" 2;
   Mixtbl.set ~inj:inj_str tbl "baaz" "hello";
-  let l = Mixtbl.keys_seq tbl |> CCSequence.to_list in
+  let l = Mixtbl.keys_seq tbl |> Sequence.to_list in
   OUnit.assert_equal ["baaz"; "bar"; "foo"] (List.sort compare l);
   ()
 
@@ -78,9 +78,9 @@ let test_bindings () =
   Mixtbl.set ~inj:inj_int tbl "bar" 2;
   Mixtbl.set ~inj:inj_str tbl "baaz" "hello";
   Mixtbl.set ~inj:inj_str tbl "str" "rts";
-  let l_int = Mixtbl.bindings_of tbl ~inj:inj_int |> CCSequence.to_list in
+  let l_int = Mixtbl.bindings_of tbl ~inj:inj_int |> Sequence.to_list in
   OUnit.assert_equal ["bar", 2; "foo", 1] (List.sort compare l_int);
-  let l_str = Mixtbl.bindings_of tbl ~inj:inj_str |> CCSequence.to_list in
+  let l_str = Mixtbl.bindings_of tbl ~inj:inj_str |> Sequence.to_list in
   OUnit.assert_equal ["baaz", "hello"; "str", "rts"] (List.sort compare l_str);
   ()
 
diff --git a/tests/test_pHashtbl.ml b/tests/test_pHashtbl.ml
index ce663ecd..c00f0d27 100644
--- a/tests/test_pHashtbl.ml
+++ b/tests/test_pHashtbl.ml
@@ -2,7 +2,7 @@
 open OUnit
 open Containers_misc
 
-module Sequence = CCSequence
+
 
 let test_add () =
   let h = PHashtbl.create 5 in
diff --git a/tests/test_splayMap.ml b/tests/test_splayMap.ml
index aa22a5a1..fb1d85b8 100644
--- a/tests/test_splayMap.ml
+++ b/tests/test_splayMap.ml
@@ -2,7 +2,7 @@
 open OUnit
 open Containers_misc
 
-module Sequence = CCSequence
+
 
 let test1 () =
   let empty = SplayMap.empty () in
diff --git a/tests/test_vector.ml b/tests/test_vector.ml
index 878937a4..c8ece7c6 100644
--- a/tests/test_vector.ml
+++ b/tests/test_vector.ml
@@ -2,7 +2,7 @@
 open OUnit
 
 module Vector = CCVector
-module Sequence = CCSequence
+
 
 let test_clear () =
   let v = Vector.of_seq Sequence.(1 -- 10) in
diff --git a/tests/threads/test_future.ml b/tests/threads/test_future.ml
index 4c7bdf18..cabb7f39 100644
--- a/tests/threads/test_future.ml
+++ b/tests/threads/test_future.ml
@@ -15,9 +15,9 @@ let test_mvar () =
   ()
 
 let test_parallel () =
-  let l = CCSequence.(1 -- 300) in
-  let l = CCSequence.map (fun _ -> Future.spawn (fun () -> Thread.delay 0.1; 1)) l in
-  let l = CCSequence.to_list l in
+  let l = Sequence.(1 -- 300) in
+  let l = Sequence.map (fun _ -> Future.spawn (fun () -> Thread.delay 0.1; 1)) l in
+  let l = Sequence.to_list l in
   let l' = List.map Future.get l in
   OUnit.assert_equal 300 (List.fold_left (+) 0 l');
   ()