From 5a4d25b93934bfca5ca5f4ccfddec1ab90a4ef2a Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Mon, 31 Aug 2015 13:42:13 +0200
Subject: [PATCH] add `CCKList.{of_array,to_array}`

---
 src/iter/CCKList.ml  | 27 +++++++++++++++++++++++++++
 src/iter/CCKList.mli |  8 ++++++++
 2 files changed, 35 insertions(+)

diff --git a/src/iter/CCKList.ml b/src/iter/CCKList.ml
index 042dba39..0b7de890 100644
--- a/src/iter/CCKList.ml
+++ b/src/iter/CCKList.ml
@@ -334,6 +334,33 @@ let of_list l =
     | x::l' -> `Cons (x, aux l')
   in aux l
 
+let of_array a =
+  let rec aux a i () =
+    if i=Array.length a then `Nil
+    else `Cons (a.(i), aux a (i+1))
+  in
+  aux a 0
+
+let to_array l =
+  match l() with
+  | `Nil -> [| |]
+  | `Cons (x, _) ->
+    let n = length l in
+    let a = Array.make n x in (* need first elem to create [a] *)
+    iteri
+      (fun i x -> a.(i) <- x)
+      l;
+    a
+
+(*$Q
+   Q.(array int) (fun a -> of_array a |> to_array = a)
+*)
+
+(*$T
+  of_array [| 1; 2; 3 |] |> to_list = [1;2;3]
+  of_list [1;2;3] |> to_array = [| 1; 2; 3; |]
+*)
+
 let rec to_seq res k = match res () with
   | `Nil -> ()
   | `Cons (s, f) -> k s; to_seq f k
diff --git a/src/iter/CCKList.mli b/src/iter/CCKList.mli
index 564bdb79..76c94bdc 100644
--- a/src/iter/CCKList.mli
+++ b/src/iter/CCKList.mli
@@ -212,6 +212,14 @@ val of_list : 'a list -> 'a t
 val to_list : 'a t -> 'a list
 (** Gather all values into a list *)
 
+val of_array : 'a array -> 'a t
+(** Iterate on the array
+    @since NEXT_RELEASE *)
+
+val to_array : 'a t -> 'a array
+(** Convert into array. Iterates twice.
+    @since NEXT_RELEASE *)
+
 val to_rev_list : 'a t -> 'a list
 (** Convert to a list, in reverse order. More efficient than {!to_list} *)