add CCHeap.to_seq_sorted

src/core/CCHeap.ml

@@ -69,6 +69,15 @@ end
   )
 *)
 
+(*$QR
+  Q.(list_of_size Gen.(return 1_000) int) (fun l ->
+    (* put elements into a heap *)
+    let h = H.of_seq (Sequence.of_list l) in
+    let l' = H.to_seq_sorted h |> Sequence.to_list in
+    is_sorted l'
+  )
+*)
+
 module type S = sig
   type elt
   type t
@@ -146,6 +155,10 @@ module type S = sig
 
   val to_seq : t -> elt sequence
 
+  val to_seq_sorted : t -> elt sequence
+  (** Iterate on the elements, in increasing order
+      @since NEXT_RELEASE *)
+
   val add_klist : t -> elt klist -> t (** @since 0.16 *)
 
   val of_klist : elt klist -> t
@@ -273,6 +286,13 @@ module Make(E : PARTIAL_ORD) : S with type elt = E.t = struct
 
   let to_seq h k = iter k h
 
+  let to_seq_sorted heap =
+    let rec recurse h k = match take h with
+      | None -> ()
+      | Some (h',x) -> k x; recurse h' k
+    in
+    fun k -> recurse heap k
+
   let rec add_klist h l = match l() with
     | `Nil -> h
     | `Cons (x, l') ->

src/core/CCHeap.mli

@@ -92,6 +92,10 @@ module type S = sig
 
   val to_seq : t -> elt sequence
 
+  val to_seq_sorted : t -> elt sequence
+  (** Iterate on the elements, in increasing order
+      @since NEXT_RELEASE *)
+
   val add_klist : t -> elt klist -> t (** @since 0.16 *)
 
   val of_klist : elt klist -> t