Usage of Seq.of_dispenser

Learning
1

Hello,
I am trying to learn how to use Seq.of_dispenser and my function is this.


 let get_containing_data nodes point =
  (* TODO Check if 'point' it is out of bounds *)
  let mid = point in
  let en_d = Int.sub (Int.of_float( log2 (Int.to_float (2 lsl (CCVector.length nodes)))))  1 in
  Seq.of_dispenser (fun _ ->
           let rec loop_while mid =
           if Int.(<) mid  en_d then
                try
                   let n = CCVector.get nodes mid in
                   let popped =
                        if CCVector.exists (fun ((start : int), _) -> Int.(<=) start point) n.by_start then
                           CCVector.pop n.by_start
                        else if CCVector.exists (fun (en_d, _) ->  Int.(<=) point en_d ) n.by_start then
                           CCVector.pop n.by_start
                        else None in
                   (match popped with
                    | Some (_,id) -> Some id
                    | None ->
                       let mid = (mid lor (Int.add mid  1)) land lnot (2 lsl (trailing_ones (Int64.of_int mid))) in
                       loop_while mid
                  )
                with Invalid_argument _mid-> Printf.printf "Invalid_Argument"; None
          else None
         in loop_while mid
         )

node is

type node = {
    by_start : (int * int) Node_vector.vector;
    by_end : (int * int) Node_vector.vector
}
type interval_tree = {
    nodes : node Interval_vector.vector;
}

The type of my function is shown as (node, `a) Internal_Vector.t -> int -> int -> BatSeq.node
I believe I am returning an int. What does BatSeq.node mean here ? I couldn’t print the int Seq.node type.

What are the usecases for of_dispenser ? Here I am using it to search for a value in a data structure(range) repeatedly.

Thanks.

2

This may be part of the answer.

let%expect_test "Find interval"=

      let node = new_range 32 (generate_range()) in
      Seq.iter print_int( fun() -> get_containing_data node (generate_point()) ());
      [%expect {| |}]