1 files changed, 74 insertions, 0 deletions
diff --git a/aoc2023-gleam/src/utilities/array2d.gleam b/aoc2023-gleam/src/utilities/array2d.gleam
new file mode 100644
index 0000000..8538129
--- /dev/null
+++ b/aoc2023-gleam/src/utilities/array2d.gleam
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+import gleam/list
+import gleam/dict.{type Dict}
+import gleam/string
+import gleam/int
+import gleam/result
+
+pub type Posn {
+  Posn(r: Int, c: Int)
+}
+
+pub type Array2D(a) =
+  Dict(Posn, a)
+
+pub fn add_posns(p1: Posn, p2: Posn) -> Posn {
+  case p1, p2 {
+    Posn(r1, c1), Posn(r2, c2) -> Posn(r1 + r2, c1 + c2)
+  }
+}
+
+pub fn ortho_neighbors(p: Posn) -> List(Posn) {
+  let Posn(r, c) = p
+  [Posn(r + 1, c), Posn(r - 1, c), Posn(r, c + 1), Posn(r, c - 1)]
+}
+
+pub fn to_2d_array(xss: List(List(a))) -> Array2D(a) {
+  to_2d_array_using(xss, fn(x) { Ok(x) })
+}
+
+pub fn to_2d_array_using(
+  xss: List(List(a)),
+  f: fn(a) -> Result(b, Nil),
+) -> Array2D(b) {
+  {
+    use r, row <- list.index_map(xss)
+    use c, cell <- list.index_map(row)
+    case f(cell) {
+      Ok(contents) -> Ok(#(Posn(r, c), contents))
+      Error(Nil) -> Error(Nil)
+    }
+  }
+  |> list.flatten
+  |> result.values
+  |> dict.from_list
+}
+
+pub fn to_2d_intarray(xss: List(List(String))) -> Array2D(Int) {
+  {
+    use r, row <- list.index_map(xss)
+    use c, cell <- list.index_map(row)
+    let assert Ok(n) = int.parse(cell)
+    #(Posn(r, c), n)
+  }
+  |> list.flatten
+  |> dict.from_list
+}
+
+pub fn to_list_of_lists(str: String) -> List(List(String)) {
+  str
+  |> string.split("\n")
+  |> list.map(string.to_graphemes)
+}
+
+pub fn parse_grid(str: String) -> Array2D(String) {
+  parse_grid_using(str, fn(x) { Ok(x) })
+}
+
+pub fn parse_grid_using(
+  str: String,
+  f: fn(String) -> Result(a, Nil),
+) -> Array2D(a) {
+  str
+  |> to_list_of_lists
+  |> to_2d_array_using(f)
+}