Moved Grid to Aoc module.

lib/aoc.mli

@@ -74,3 +74,50 @@ module IntPairSet : sig
   val add_seq : elt Seq.t -> t -> t
   val of_seq : elt Seq.t -> t
 end
+
+(** The [Grid] module is used to represent and manipulate a grid of characters.
+    Its main goals are to be non-mutable and have constant access times to
+    locations in the grid.
+
+    Grid locations can be accessed by index or (col, row) position. Indicies do
+    not guarantee an ordering on accesses - but iterating by index from 0 to
+    [Grid.length grid - 1] inclusive will cover the whole grid. *)
+module Grid : sig
+  type t
+  (** The type used to represent a grid *)
+
+  val of_file : string -> t
+  (** [Grid.of_file fname] returns a grid loaded from the file [fname] *)
+
+  val length : t -> int
+  (** [Grid.length grid] returns the length of the grid. *)
+
+  val get_by_idx : t -> int -> char
+  (** [Grid.get_by_idx grid idx] returns the character at index [idx] in [grid].
+  *)
+
+  val get_by_pos : t -> int * int -> char
+  (** [Grid.get_by_pos grid pos] returns the character at position [pos] in
+      [grid]. *)
+
+  val pos_of_idx : t -> int -> int * int
+  (** [Grid.pos_of_idx grid idx] returns the [(x, y)] position mapped by [idx]
+      in [grid]. *)
+
+  val idx_of_pos : t -> int * int -> int
+  (** [Grid.pos_of_idx grid pos] returns the index corresponding to [pos] in
+      [grid]. *)
+
+  val pos_is_valid : t -> int * int -> bool
+  (** [Grid.pos_is_valid grid pos] returns [true] if and only if [pos] is a
+      valid position in [grid]. *)
+
+  val idx_from_opt : t -> int -> char -> int option
+  (** [Grid.idx_from_opt grid start c] returns [Some idx] where [idx] is the
+      first location in [grid] at or after the [start] index which is [c]. It
+      returns [None] if [c] does not appear. *)
+
+  val update_pos : t -> int * int -> char -> t
+  (** [Grid.update_pos grid pos c] returns a grid with the character at position
+      [pos] changed to [c]. *)
+end