diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3915aef..cf96d4e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,29 @@
 # Changelog
 
+## 0.10
+
+- add `{union,inter,diff,subset}`
+- add `{join_by,join_all_by,group_join_by}`
+- add `find_map{,i}` as better alias to existing functions
+- add `{max_exn,min_exn}`
+- add `count`
+- add `doc` and `test` to opam
+
+## 0.9
+
+- distinction between `diagonal,diagonal_l`
+- add `init,fold_map,fold_filter_map,sorted,diagonal,findi,…`
+- fix a few typos
+- update readme: convert into asciidoc, add tutorial
+- remove deprecated functions, add missing links to `SequenceLabels`
+
+## 0.8
+
+- loop based implementation for `int_range_by`
+- move files to 'src/', use qtest for tests
+- add `int_range_by`
+- add `Sequence.flat_map_l`
+
 ## 0.7
 
 - add missing entry in changelog and missing since annotations
diff --git a/README.adoc b/README.adoc
index ab9fc56..719d098 100644
--- a/README.adoc
+++ b/README.adoc
@@ -13,6 +13,8 @@ way of iterating on a finite number of values, only allocating (most of the time
 one intermediate closure to do so. For instance, iterating on keys, or values,
 of a `Hashtbl.t`, without creating a list.
 
+toc::[]
+
 == Documentation
 
 There is only one important type, `'a Sequence.t`, and lots of functions built
@@ -93,7 +95,6 @@ underlying hash function):
 - : int = 11
 
 (* now to get the values *)
-# Sequence.of_t
 # Sequence.of_hashtbl h |> Sequence.map snd |> Sequence.to_list;;
 - : string list = ["6"; "2"; "8"; "7"; "3"; "5"; "4"; "9"; "0"; "10"; "1"] 
 ----
@@ -120,7 +121,7 @@ use `Sequence.(--) : int -> int -> int Sequence.t`.
 
 NOTE: with **flambda** under sufficiently strong
 optimization flags, such compositions of operators
-will be compiled to an actual loop with no overhead!
+should be compiled to an actual loop with no overhead!
 
 === Iterating on sub-trees
 
@@ -168,6 +169,7 @@ enumerating the ways we can insert an element in a list.
 
 [source,OCaml]
 ----
+# open Sequence.Infix;;
 # module S = Sequence ;;
 # let rec insert x l = match l with
   | [] -> S.return [x]
diff --git a/_oasis b/_oasis
index eb4824c..ce827cf 100644
--- a/_oasis
+++ b/_oasis
@@ -1,6 +1,6 @@
 OASISFormat: 0.4
 Name:        sequence
-Version:     0.9
+Version:     0.10
 Homepage:    https://github.com/c-cube/sequence
 Authors:     Simon Cruanes
 License:     BSD-2-clause
diff --git a/opam b/opam
index 4b4684e..9f3cdf6 100644
--- a/opam
+++ b/opam
@@ -1,6 +1,6 @@
 opam-version: "1.2"
 name: "sequence"
-version: "0.9"
+version: "0.10"
 author: "Simon Cruanes"
 maintainer: "simon.cruanes@inria.fr"
 license: "BSD-2-clauses"
@@ -11,6 +11,14 @@ build: [
     ]
     [make "build"]
 ]
+build-doc: [
+  ["./configure" "--enable-docs"]
+  [make "doc"]
+]
+build-test: [
+  ["./configure" "--enable-tests"]
+  [make "test"]
+]
 install: [make "install"]
 remove: [
     ["ocamlfind" "remove" "sequence"]
diff --git a/setup.ml b/setup.ml
index 7c29a5c..58904ac 100644
--- a/setup.ml
+++ b/setup.ml
@@ -1,7 +1,7 @@
 (* setup.ml generated for the first time by OASIS v0.4.4 *)
 
 (* OASIS_START *)
-(* DO NOT EDIT (digest: fc3602a8b67872256edf65d37d0266b7) *)
+(* DO NOT EDIT (digest: b6facd5b08b6b1360edc26bd90d50fa3) *)
 (*
    Regenerated by OASIS v0.4.8
    Visit http://oasis.forge.ocamlcore.org for more information and
@@ -7037,7 +7037,7 @@ let setup_t =
        {
           oasis_version = "0.4";
           ocaml_version = None;
-          version = "0.9";
+          version = "0.10";
           license =
             OASISLicense.DEP5License
               (OASISLicense.DEP5Unit
@@ -8243,7 +8243,7 @@ let setup_t =
        };
      oasis_fn = Some "_oasis";
      oasis_version = "0.4.8";
-     oasis_digest = Some "\198\255:M\202\255\011Hi\149\143\207P\190g\219";
+     oasis_digest = Some "o\181u\130\246\134[37Z-Cy\216\208\151";
      oasis_exec = None;
      oasis_setup_args = [];
      setup_update = false
diff --git a/src/META b/src/META
index f3bbb7d..13249a4 100644
--- a/src/META
+++ b/src/META
@@ -1,6 +1,6 @@
 # OASIS_START
-# DO NOT EDIT (digest: b247543864e9cc39f327533c7e23c440)
-version = "0.9"
+# DO NOT EDIT (digest: 47d925b722c4289a923085abbf97bba8)
+version = "0.10"
 description = "Simple sequence (iterator) datatype and combinators"
 requires = "bytes"
 archive(byte) = "sequence.cma"
@@ -9,7 +9,7 @@ archive(native) = "sequence.cmxa"
 archive(native, plugin) = "sequence.cmxs"
 exists_if = "sequence.cma"
 package "invert" (
- version = "0.9"
+ version = "0.10"
  description = "Simple sequence (iterator) datatype and combinators"
  requires = "sequence delimcc"
  archive(byte) = "invert.cma"
@@ -20,7 +20,7 @@ package "invert" (
 )
 
 package "bigarray" (
- version = "0.9"
+ version = "0.10"
  description = "Simple sequence (iterator) datatype and combinators"
  requires = "sequence bigarray"
  archive(byte) = "bigarray.cma"
diff --git a/src/sequence.ml b/src/Sequence.ml
similarity index 84%
rename from src/sequence.ml
rename to src/Sequence.ml
index 425bf8d..3bdb9fc 100644
--- a/src/sequence.ml
+++ b/src/Sequence.ml
@@ -15,6 +15,9 @@ type (+'a, +'b) t2 = ('a -> 'b -> unit) -> unit
   let pp_ilist = Q.Print.(list int)
 *)
 
+type 'a equal = 'a -> 'a -> bool
+type 'a hash = 'a -> int
+
 (** Build a sequence from a iter function *)
 let from_iter f = f
 
@@ -411,6 +414,28 @@ let group_by (type k) ?(hash=Hashtbl.hash) ?(eq=(=)) seq =
     |> OUnit.assert_equal [[1];[2;2;2];[3;3;3];[4]]
 *)
 
+let count (type k) ?(hash=Hashtbl.hash) ?(eq=(=)) seq =
+  let module Tbl = Hashtbl.Make(struct
+      type t = k
+      let equal = eq
+      let hash = hash
+    end) in
+  (* compute group table *)
+  let tbl = Tbl.create 32 in
+  seq
+    (fun x ->
+       let n = try Tbl.find tbl x with Not_found -> 0 in
+       Tbl.replace tbl x (n+1)
+    );
+  fun yield ->
+    Tbl.iter (fun x n -> yield (x,n)) tbl
+
+(*$R
+  [1;2;3;3;2;2;3;4]
+    |> of_list |> count ?eq:None ?hash:None |> sort ?cmp:None |> to_list
+    |> OUnit.assert_equal [1,1;2,3;3,3;4,1]
+*)
+
 let uniq ?(eq=fun x y -> x = y) seq k =
   let has_prev = ref false
   and prev = ref (Obj.magic 0) in  (* avoid option type, costly *)
@@ -499,6 +524,142 @@ let join ~join_row s1 s2 k =
   OUnit.assert_equal ["1 = 1"; "2 = 2"] (to_list s);
 *)
 
+let join_by (type a) ?(eq=(=)) ?(hash=Hashtbl.hash) f1 f2 ~merge c1 c2 =
+  let module Tbl = Hashtbl.Make(struct
+      type t = a
+      let equal = eq
+      let hash = hash
+    end) in
+  let tbl = Tbl.create 32 in
+  c1
+    (fun x ->
+       let key = f1 x in
+       Tbl.add tbl key x);
+  let res = ref [] in
+  c2
+    (fun y ->
+       let key = f2 y in
+       let xs = Tbl.find_all tbl key in
+       List.iter
+         (fun x -> match merge key x y with
+            | None -> ()
+            | Some z -> res := z :: !res)
+         xs);
+  fun yield -> List.iter yield !res
+
+type ('a, 'b) join_all_cell = {
+  mutable ja_left: 'a list;
+  mutable ja_right: 'b list;
+}
+
+let join_all_by (type a) ?(eq=(=)) ?(hash=Hashtbl.hash) f1 f2 ~merge c1 c2 =
+  let module Tbl = Hashtbl.Make(struct
+      type t = a
+      let equal = eq
+      let hash = hash
+    end) in
+  let tbl = Tbl.create 32 in
+  (* build the map [key -> cell] *)
+  c1
+    (fun x ->
+       let key = f1 x in
+       try
+         let c = Tbl.find tbl key in
+         c.ja_left <- x :: c.ja_left
+       with Not_found ->
+         Tbl.add tbl key {ja_left=[x]; ja_right=[]});
+  c2
+    (fun y ->
+       let key = f2 y in
+       try
+         let c = Tbl.find tbl key in
+         c.ja_right <- y :: c.ja_right
+       with Not_found ->
+         Tbl.add tbl key {ja_left=[]; ja_right=[y]});
+  let res = ref [] in
+  Tbl.iter
+    (fun key cell -> match merge key cell.ja_left cell.ja_right with
+       | None -> ()
+       | Some z -> res := z :: !res)
+    tbl;
+  fun yield -> List.iter yield !res
+
+let group_join_by (type a) ?(eq=(=)) ?(hash=Hashtbl.hash) f c1 c2 =
+  let module Tbl = Hashtbl.Make(struct
+      type t = a
+      let equal = eq
+      let hash = hash
+    end) in
+  let tbl = Tbl.create 32 in
+  c1 (fun x -> Tbl.replace tbl x []);
+  c2
+    (fun y ->
+       (* project [y] into some element of [c1] *)
+       let key = f y in
+       try
+         let l = Tbl.find tbl key in
+         Tbl.replace tbl key (y :: l)
+       with Not_found -> ());
+  fun yield -> Tbl.iter (fun k l -> yield (k,l)) tbl
+
+(*$=
+  ['a', ["abc"; "attic"]; \
+   'b', ["barbary"; "boom"; "bop"]; \
+   'c', []] \
+  (group_join_by (fun s->s.[0]) \
+    (of_str "abc") \
+    (of_list ["abc"; "boom"; "attic"; "deleted"; "barbary"; "bop"]) \
+  |> map (fun (c,l)->c,List.sort Pervasives.compare l) \
+  |> sort |> to_list)
+*)
+
+let union (type a) ?(eq=(=)) ?(hash=Hashtbl.hash) c1 c2 =
+  let module Tbl = Hashtbl.Make(struct
+      type t = a let equal = eq let hash = hash end) in
+  let tbl = Tbl.create 32 in
+  c1 (fun x -> Tbl.replace tbl x ());
+  c2 (fun x -> Tbl.replace tbl x ());
+  fun yield -> Tbl.iter (fun x _ -> yield x) tbl
+
+type inter_status =
+  | Inter_left
+  | Inter_both
+
+let inter (type a) ?(eq=(=)) ?(hash=Hashtbl.hash) c1 c2 =
+  let module Tbl = Hashtbl.Make(struct
+      type t = a let equal = eq let hash = hash end) in
+  let tbl = Tbl.create 32 in
+  c1 (fun x -> Tbl.replace tbl x Inter_left);
+  c2
+    (fun x ->
+       try
+         match Tbl.find tbl x with
+           | Inter_left ->
+             Tbl.replace tbl x Inter_both; (* save *)
+           | Inter_both -> ()
+       with Not_found -> ());
+  fun yield -> Tbl.iter (fun x res -> if res=Inter_both then yield x) tbl
+
+let diff (type a) ?(eq=(=)) ?(hash=Hashtbl.hash) c1 c2 =
+  let module Tbl = Hashtbl.Make(struct
+      type t = a let equal = eq let hash = hash end) in
+  let tbl = Tbl.create 32 in
+  c2 (fun x -> Tbl.replace tbl x ());
+  fun yield ->
+    c1 (fun x -> if not (Tbl.mem tbl x) then yield x)
+
+exception Subset_exit
+
+let subset (type a) ?(eq=(=)) ?(hash=Hashtbl.hash) c1 c2 =
+  let module Tbl = Hashtbl.Make(struct
+      type t = a let equal = eq let hash = hash end) in
+  let tbl = Tbl.create 32 in
+  c2 (fun x -> Tbl.replace tbl x ());
+  try
+    c1 (fun x -> if not (Tbl.mem tbl x) then raise Subset_exit);
+    true
+  with Subset_exit -> false
+
 let rec unfoldr f b k = match f b with
   | None -> ()
   | Some (x, b') ->
@@ -532,6 +693,10 @@ let max ?(lt=fun x y -> x < y) seq =
       | Some y -> if lt y x then ret := Some x);
   !ret
 
+let max_exn ?lt seq = match max ?lt seq with
+  | Some x -> x
+  | None -> raise Not_found
+
 let min ?(lt=fun x y -> x < y) seq =
   let ret = ref None in
   seq
@@ -540,6 +705,15 @@ let min ?(lt=fun x y -> x < y) seq =
       | Some y -> if lt x y then ret := Some x);
   !ret
 
+let min_exn ?lt seq = match min ?lt seq with
+  | Some x -> x
+  | None -> raise Not_found
+
+(*$= & ~printer:string_of_int
+  100 (0 -- 100 |> max_exn ?lt:None)
+  0 (0 -- 100 |> min_exn ?lt:None)
+*)
+
 exception ExitHead
 
 let head seq =
@@ -664,7 +838,7 @@ let mem ?(eq=(=)) x seq = exists (eq x) seq
 
 exception ExitFind
 
-let find f seq =
+let find_map f seq =
   let r = ref None in
   begin
     try
@@ -676,7 +850,9 @@ let find f seq =
   end;
   !r
 
-let findi f seq =
+let find = find_map
+
+let find_mapi f seq =
   let i = ref 0 in
   let r = ref None in
   begin
@@ -689,7 +865,9 @@ let findi f seq =
   end;
   !r
 
-let find_pred f seq = find (fun x -> if f x then Some x else None) seq
+let findi = find_mapi
+
+let find_pred f seq = find_map (fun x -> if f x then Some x else None) seq
 
 let find_pred_exn f seq = match find_pred f seq with
   | Some x -> x
diff --git a/src/sequence.mli b/src/Sequence.mli
similarity index 87%
rename from src/sequence.mli
rename to src/Sequence.mli
index 40406f0..a510c99 100644
--- a/src/sequence.mli
+++ b/src/Sequence.mli
@@ -39,6 +39,9 @@ type +'a sequence = 'a t
 type (+'a, +'b) t2 = ('a -> 'b -> unit) -> unit
 (** Sequence of pairs of values of type ['a] and ['b]. *)
 
+type 'a equal = 'a -> 'a -> bool
+type 'a hash = 'a -> int
+
 (** {2 Build a sequence} *)
 
 val from_iter : (('a -> unit) -> unit) -> 'a t
@@ -144,10 +147,18 @@ val find : ('a -> 'b option) -> 'a t -> 'b option
 (** Find the first element on which the function doesn't return [None]
     @since 0.5 *)
 
+val find_map : ('a -> 'b option) -> 'a t -> 'b option
+(** Alias to {!find}
+    @since 0.10 *)
+
 val findi : (int -> 'a -> 'b option) -> 'a t -> 'b option
 (** Indexed version of {!find}
     @since 0.9 *)
 
+val find_mapi : (int -> 'a -> 'b option) -> 'a t -> 'b option
+(** Alias to {!findi}
+    @since 0.10 *)
+
 val find_pred : ('a -> bool) -> 'a t -> 'a option
 (** [find_pred p l] finds the first element of [l] that satisfies [p],
     or returns [None] if no element satisfies [p]
@@ -241,6 +252,12 @@ val group_by : ?hash:('a -> int) -> ?eq:('a -> 'a -> bool) ->
     The result sequence is traversable as many times as required.
     @since 0.6 *)
 
+val count : ?hash:('a -> int) -> ?eq:('a -> 'a -> bool) ->
+  'a t -> ('a * int) t
+(** Map each distinct element to its number of occurrences in the whole seq.
+    Similar to [group_by seq |> map (fun l->List.hd l, List.length l)]
+    @since 0.10 *)
+
 val uniq : ?eq:('a -> 'a -> bool) -> 'a t -> 'a t
 (** Remove consecutive duplicate elements. Basically this is
     like [fun seq -> map List.hd (group seq)]. *)
@@ -271,6 +288,93 @@ val join : join_row:('a -> 'b -> 'c option) -> 'a t -> 'b t -> 'c t
     the two elements do not combine. Assume that [b] allows for multiple
     iterations. *)
 
+val join_by : ?eq:'key equal -> ?hash:'key hash ->
+  ('a -> 'key) -> ('b -> 'key) ->
+  merge:('key -> 'a -> 'b -> 'c option) ->
+  'a t ->
+  'b t ->
+  'c t
+(** [join key1 key2 ~merge] is a binary operation
+    that takes two sequences [a] and [b], projects their
+    elements resp. with [key1] and [key2], and combine
+    values [(x,y)] from [(a,b)] with the same [key]
+    using [merge]. If [merge] returns [None], the combination
+    of values is discarded.
+    @since 0.10 *)
+
+val join_all_by : ?eq:'key equal -> ?hash:'key hash ->
+  ('a -> 'key) -> ('b -> 'key) ->
+  merge:('key -> 'a list -> 'b list -> 'c option) ->
+  'a t ->
+  'b t ->
+  'c t
+(** [join_all_by key1 key2 ~merge] is a binary operation
+    that takes two sequences [a] and [b], projects their
+    elements resp. with [key1] and [key2], and, for each key [k]
+    occurring in at least one of them:
+    - compute the list [l1] of elements of [a] that map to [k]
+    - compute the list [l2] of elements of [b] that map to [k]
+    - call [merge k l1 l2]. If [merge] returns [None], the combination
+      of values is discarded, otherwise it returns [Some c]
+      and [c] is inserted in the result.
+    @since 0.10 *)
+
+val group_join_by : ?eq:'a equal -> ?hash:'a hash ->
+  ('b -> 'a) ->
+  'a t ->
+  'b t ->
+  ('a * 'b list) t
+(** [group_join_by key2] associates to every element [x] of
+    the first sequence, all the elements [y] of the second
+    sequence such that [eq x (key y)]. Elements of the first
+    sequences without corresponding values in the second one
+    are mapped to [[]]
+    @since 0.10 *)
+
+val inter :
+  ?eq:'a equal -> ?hash:'a hash ->
+  'a t -> 'a t -> 'a t
+(** Intersection of two collections. Each element will occur at most once
+    in the result. Eager.
+    @since 0.10 *)
+
+(*$=
+  [2;4;5;6] (inter (1--6) (cons 2 (4--10)) |> sort |> to_list)
+  [] (inter (0--5) (6--10) |> to_list)
+*)
+
+val union :
+  ?eq:'a equal -> ?hash:'a hash ->
+  'a t -> 'a t -> 'a t
+(** Union of two collections. Each element will occur at most once
+    in the result. Eager.
+    @since 0.10 *)
+
+(*$=
+  [2;4;5;6] (union (4--6) (cons 2 (4--5)) |> sort |> to_list)
+*)
+
+val diff :
+  ?eq:'a equal -> ?hash:'a hash ->
+  'a t -> 'a t -> 'a t
+(** Set difference. Eager.
+    @since 0.10 *)
+
+(*$=
+  [1;2;8;9;10] (diff (1--10) (3--7) |> to_list)
+*)
+
+val subset :
+  ?eq:'a equal -> ?hash:'a hash ->
+  'a t -> 'a t -> bool
+(** [subset a b] returns [true] if all elements of [a] belong to [b]. Eager.
+    @since 0.10 *)
+
+(*$T
+  subset (2 -- 4) (1 -- 4)
+  not (subset (1 -- 4) (2 -- 10))
+*)
+
 val unfoldr : ('b -> ('a * 'b) option) -> 'b -> 'a t
 (** [unfoldr f b] will apply [f] to [b]. If it
     yields [Some (x,b')] then [x] is returned
@@ -284,10 +388,20 @@ val max : ?lt:('a -> 'a -> bool) -> 'a t -> 'a option
     @return None if the sequence is empty, Some [m] where [m] is the maximal
     element otherwise *)
 
+val max_exn : ?lt:('a -> 'a -> bool) -> 'a t -> 'a
+(** Unsafe version of {!max}
+    @raise Not_found if the sequence is empty
+    @since 0.10 *)
+
 val min : ?lt:('a -> 'a -> bool) -> 'a t -> 'a option
 (** Min element of the sequence, using the given comparison function.
     see {!max} for more details. *)
 
+val min_exn : ?lt:('a -> 'a -> bool) -> 'a t -> 'a
+(** Unsafe version of {!min}
+    @raise Not_found if the sequence is empty
+    @since 0.10 *)
+
 val head : 'a t -> 'a option
 (** First element, if any, otherwise [None]
     @since 0.5.1 *)
diff --git a/src/sequenceLabels.ml b/src/sequenceLabels.ml
index 663d7cb..b990b32 120000
--- a/src/sequenceLabels.ml
+++ b/src/sequenceLabels.ml
@@ -1 +1 @@
-sequence.ml
\ No newline at end of file
+Sequence.ml
\ No newline at end of file
diff --git a/src/sequenceLabels.mli b/src/sequenceLabels.mli
index 06bd60f..b28e492 100644
--- a/src/sequenceLabels.mli
+++ b/src/sequenceLabels.mli
@@ -212,6 +212,12 @@ val group_by : ?hash:('a -> int) -> ?eq:('a -> 'a -> bool) ->
     The result sequence is traversable as many times as required.
     @since 0.6 *)
 
+val count : ?hash:('a -> int) -> ?eq:('a -> 'a -> bool) ->
+  'a t -> ('a * int) t
+(** Map each distinct element to its number of occurrences in the whole seq.
+    Similar to [group_by seq |> map (fun l->List.hd l, List.length l)]
+    @since 0.10 *)
+
 val uniq : ?eq:('a -> 'a -> bool) -> 'a t -> 'a t
 (** Remove consecutive duplicate elements. Basically this is
     like [fun seq -> map List.hd (group seq)]. *)