a few helpers + 1 example

core/CCLinq.ml

@@ -137,6 +137,7 @@ 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))
     | _ ->
         to_seq c |> set_of_seq ~cmp
 
@@ -228,7 +229,7 @@ module Map = struct
         M.fold
           (fun key set acc -> f acc key set) !map acc
       );
-      to_seq = M.to_seq !map;
+      to_seq = (fun k -> M.to_seq !map k);
     } in
     {
       cur;
@@ -281,11 +282,10 @@ module Map = struct
 
   let count build seq =
     seq (fun x ->
-      let n = match build.cur.get x with
+      build.update x
-        | None -> 1
+        (function
-        | Some n -> n+1
+            | None -> Some 1
-      in
+            | Some n -> Some (n+1)));
-      build.add x n);
     build.cur
 
   let get m x = m.get x
@@ -298,6 +298,8 @@ module Map = struct
   let size m = m.size ()
 
   let to_seq m = m.to_seq
+
+  let to_list m = m.to_seq |> CCSequence.to_rev_list
 end
 
 (** {2 Query operators} *)
@@ -538,11 +540,15 @@ let flat_map_seq f q =
   let f' x = Coll.of_seq (f x) in
   Unary (FlatMap f', q)
 
+let flat_map_list f q =
+  let f' x = Coll.of_list (f x) in
+  Unary (FlatMap f', q)
+
 let take n q = Unary (Take n, q)
 
 let take_while p q = Unary (TakeWhile p, q)
 
-let sort ~cmp q = Unary (Sort cmp, q)
+let sort ?(cmp=Pervasives.compare) () q = Unary (Sort cmp, q)
 
 let distinct ?(cmp=Pervasives.compare) () q =
   Unary (Distinct cmp, q)
@@ -553,10 +559,10 @@ let get key q =
 let get_exn key q =
   Unary (Get (Unsafe, key), q)
 
-let map_to_seq q =
+let map_iter q =
   Unary (GeneralMap (fun m -> Coll.of_seq m.Map.to_seq), q)
 
-let map_to_seq_flatten q =
+let map_iter_flatten q =
   let f m = m.Map.to_seq
       |> CCSequence.flatMap
         (fun (k,v) -> Coll.to_seq v |> CCSequence.map (fun v' -> k,v'))
@@ -564,6 +570,9 @@ let map_to_seq_flatten q =
   in
   Unary (GeneralMap f, q)
 
+let map_to_list q =
+  Unary (GeneralMap Map.to_list, q)
+
 let group_by ?(cmp=Pervasives.compare) f q =
   Unary (GroupBy (cmp,f), q)
 
@@ -704,3 +713,7 @@ let to_queue q =
 
 let to_stack q =
   QueryMap ((fun c s -> CCSequence.to_stack s (Coll.to_seq c)), q)
+
+(** {6 Misc} *)
+
+let run_list q = run (q |> to_list)

core/CCLinq.mli

@@ -24,7 +24,25 @@ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *)
 
-(** {1 LINQ-like operations on collections} *)
+(** {1 LINQ-like operations on collections}
+
+The purpose it to provide powerful combinators to express iteration,
+transformation and combination of collections of items.
+
+{[
+
+CCLinq.(
+  start_list [1;2;3]
+  |> flat_map_list (fun x -> CCList.(x -- (x+10)))
+  |> sort ()
+  |> count ()
+  |> map_to_list |> run
+);;
+- : (int * int) list = [(13, 1); (12, 2); (11, 3); (10, 3); (9, 3);
+    (8, 3); (7, 3); (6, 3); (5, 3); (4, 3); (3, 3); (2, 2); (1, 1)]
+]}
+
+*)
 
 type 'a sequence = ('a -> unit) -> unit
 type 'a equal = 'a -> 'a -> bool
@@ -49,6 +67,8 @@ module Map : sig
   val size : (_,_) t -> int
   
   val to_seq : ('a, 'b) t -> ('a * 'b) sequence
+
+  val to_list : ('a, 'b) t -> ('a * 'b) list
 end
 
 (** {2 Query operators} *)
@@ -79,6 +99,9 @@ val run : 'a t -> 'a
 val run_no_opt : 'a t -> 'a
 (** Execute the query, without optimizing it at all *)
 
+val run_list : 'a collection t -> 'a list
+(** Shortcut to obtain a list *)
+
 (** {6 Basics on Collections} *)
 
 val map : ('a -> 'b) -> 'a collection t -> 'b collection t
@@ -104,13 +127,15 @@ val flat_map : ('a -> 'b collection) -> 'a collection t -> 'b collection t
 val flat_map_seq : ('a -> 'b sequence) -> 'a collection t -> 'b collection t
 (** Same as {!flat_map} but using sequences *)
 
+val flat_map_list : ('a -> 'b list) -> 'a collection t -> 'b collection t
+
 val take : int -> 'a collection t -> 'a collection t
 (** take at most [n] elements *)
 
 val take_while : ('a -> bool) -> 'a collection t -> 'a collection t
 (** take elements while they satisfy a predicate *)
 
-val sort : cmp:'a ord -> 'a collection t -> 'a collection t
+val sort : ?cmp:'a ord -> unit -> 'a collection t -> 'a collection t
 (** Sort items by the given comparison function *)
 
 val distinct : ?cmp:'a ord -> unit -> 'a collection t -> 'a collection t
@@ -126,12 +151,14 @@ val get_exn : 'a -> ('a, 'b) Map.t t -> 'b t
 (** Unsafe version of {!get}.
     @raise Not_found if the key is not present. *)
 
-val map_to_seq : ('a,'b) Map.t t -> ('a*'b) collection t
+val map_iter : ('a,'b) Map.t t -> ('a*'b) collection t
 (** View a multimap as a proper collection *)
 
-val map_to_seq_flatten : ('a,'b collection) Map.t t -> ('a*'b) collection t
+val map_iter_flatten : ('a,'b collection) Map.t t -> ('a*'b) collection t
 (** View a multimap as a collection of individual key/value pairs *)
 
+val map_to_list : ('a,'b) Map.t t -> ('a*'b) list t
+
 (** {6 Aggregation} *)
 
 val group_by : ?cmp:'b ord ->