add Vec2.iter_region

src/grid.ml

@@ -73,13 +73,7 @@ let of_lines parse_char lines : 'a t =
 ;;
 
 let iter_region grid a b callback =
-  let open Vec2 in
+  Vec2.iter_region a b (fun pos -> if in_bounds grid pos then callback pos)
-  for y = min a.y b.y to max a.y b.y do
-    for x = min a.x b.x to max a.x b.x do
-      let pos = { x; y } in
-      if in_bounds grid pos then callback pos
-    done
-  done
 ;;
 
 let iter grid callback =

src/vec2.ml

@@ -19,3 +19,11 @@ let ( + ) a b = { x = a.x + b.x; y = a.y + b.y }
 let ( - ) a b = { x = a.x - b.x; y = a.y - b.y }
 let ( = ) a b = a.x = b.x && a.y = b.y
 let abs a = Int.{ x = abs a.x; y = abs a.y }
+
+let iter_region a b callback =
+  for y = min a.y b.y to max a.y b.y do
+    for x = min a.x b.x to max a.x b.x do
+      callback { x; y }
+    done
+  done
+;;

src/vec2.mli

@@ -17,3 +17,4 @@ val ( + ) : t -> t -> t
 val ( - ) : t -> t -> t
 val ( = ) : t -> t -> bool
 val abs : t -> t
+val iter_region : t -> t -> (t -> unit) -> unit