move grid parse & iter into Vec2

src/day8.ml

@@ -1,28 +1,13 @@
 open Containers
 
 let parse_grid () =
-  let lines = Utils.lines_of_input 8 in
-  lines
-  |> Array.of_list
-  |> Array.map
-       Fun.(String.to_seq %> Seq.map (Char.to_string %> int_of_string) %> Seq.to_array)
-;;
-
-let solve grid fn =
-  let grid_h = Array.length grid in
-  let grid_w = Array.length grid.(0) in
-  for y = 0 to grid_h - 1 do
-    for x = 0 to grid_w - 1 do
-      let start = Vec2.of_tuple (x, y) in
-      fn start
-    done
-  done
+  Vec2.parse_grid Fun.(Char.to_string %> int_of_string) @@ Utils.lines_of_input 8
 ;;
 
 let part1 () =
   let grid = parse_grid () in
   let num_visible = ref 0 in
-  solve grid (fun start ->
+  Vec2.iter_grid grid (fun start ->
     let start_height = Option.get_exn_or "unreachable" @@ Vec2.at grid start in
     let rec walk_shorter_trees start step =
       let next = Vec2.(start + step) in
@@ -43,7 +28,7 @@ let part1 () =
 let part2 () =
   let grid = parse_grid () in
   let best_score = ref 0 in
-  solve grid (fun start ->
+  Vec2.iter_grid grid (fun start ->
     let start_height = Option.get_exn_or "unreachable" @@ Vec2.at grid start in
     let rec trees_in_view start in_view step =
       let next = Vec2.(start + step) in

src/vec2.ml

@@ -1,6 +1,7 @@
 open Containers
 
 type t = int * int [@@deriving show]
+type 'a grid = 'a array array
 
 let up = 0, 1
 let down = 0, -1
@@ -19,3 +20,19 @@ let at grid point =
   let* row = Array.get_safe grid y in
   Array.get_safe row x
 ;;
+
+let parse_grid parse_char lines =
+  lines
+  |> Array.of_list
+  |> Array.map Fun.(String.to_seq %> Seq.map parse_char %> Seq.to_array)
+;;
+
+let iter_grid grid callback =
+  let grid_h = Array.length grid in
+  let grid_w = Array.length grid.(0) in
+  for y = 0 to Int.(grid_h - 1) do
+    for x = 0 to Int.(grid_w - 1) do
+      callback (x, y)
+    done
+  done
+;;

src/vec2.mli

@@ -1,4 +1,5 @@
 type t [@@deriving show]
+type 'a grid
 
 val up : t
 val down : t
@@ -10,4 +11,6 @@ val to_tuple : t -> int * int
 val ( + ) : t -> t -> t
 val ( - ) : t -> t -> t
 val ( = ) : t -> t -> bool
-val at : 'a array array -> t -> 'a option
+val at : 'a grid -> t -> 'a option
+val parse_grid : (char -> 'a) -> string list -> 'a grid
+val iter_grid : 'a grid -> (t -> unit) -> unit