Adding Array.iter3.

2 files changed, 11 insertions, 0 deletions

diff --git a/clib/cArray.ml b/clib/cArray.ml
index 7249bcada0..95ae48a7ba 100644
--- a/clib/cArray.ml
+++ b/clib/cArray.ml
@@ -56,6 +56,7 @@ sig
     (int -> 'a -> 'b -> 'c -> 'd) -> 'a array -> 'b array -> 'c array -> 'd array
   val map_left : ('a -> 'b) -> 'a array -> 'b array
   val iter2_i : (int -> 'a -> 'b -> unit) -> 'a array -> 'b array -> unit
+  val iter3 : ('a -> 'b -> 'c -> unit) -> 'a array -> 'b array -> 'c array -> unit
   val fold_left_map : ('a -> 'b -> 'a * 'c) -> 'a -> 'b array -> 'a * 'c array
   val fold_right_map : ('a -> 'c -> 'b * 'c) -> 'a array -> 'c -> 'b array * 'c
   val fold_left2_map : ('a -> 'b -> 'c -> 'a * 'd) -> 'a -> 'b array -> 'c array -> 'a * 'd array
@@ -392,6 +393,13 @@ let iter2_i f v1 v2 =
   let () = if not (Int.equal len2 len1) then invalid_arg "Array.iter2" in
   for i = 0 to len1 - 1 do f i (uget v1 i) (uget v2 i) done
 
+let iter3 f v1 v2 v3 =
+  let len1 = Array.length v1 in
+  let len2 = Array.length v2 in
+  let len3 = Array.length v3 in
+  let () = if not (Int.equal len2 len1) || not (Int.equal len1 len3) then invalid_arg "Array.iter3" in
+  for i = 0 to len1 - 1 do f (uget v1 i) (uget v2 i) (uget v3 i) done
+
 let map_right f a =
   let l = length a in
   if l = 0 then [||] else begin
diff --git a/clib/cArray.mli b/clib/cArray.mli
index f40ceb56db..664bad4c0a 100644
--- a/clib/cArray.mli
+++ b/clib/cArray.mli
@@ -92,6 +92,9 @@ sig
   val iter2_i : (int -> 'a -> 'b -> unit) -> 'a array -> 'b array -> unit
   (** Iter on two arrays. Raise [Invalid_argument "Array.iter2_i"] if sizes differ. *)
 
+  val iter3 : ('a -> 'b -> 'c -> unit) -> 'a array -> 'b array -> 'c array -> unit
+  (** Iter on three arrays. Raise [Invalid_argument "Array.iter3"] if sizes differ. *)
+
   val fold_left_map : ('a -> 'b -> 'a * 'c) -> 'a -> 'b array -> 'a * 'c array
   (** [fold_left_map f e_0 [|l_1...l_n|] = e_n,[|k_1...k_n|]]
     where [(e_i,k_i)=f e_{i-1} l_i]; see also [Smart.fold_left_map] *)