Add some grid utilities

src/main/kotlin/nl/tiemenschut/aoc/lib/util/grid/Grid.kt

@@ -0,0 +1,32 @@
+package nl.tiemenschut.aoc.lib.util.grid
+
+import nl.tiemenschut.aoc.lib.util.points.Point
+import nl.tiemenschut.aoc.lib.util.points.by
+
+class Grid<T>(val data: List<MutableList<T>>) {
+    fun width() = data.size
+    fun height() = data[0].size
+
+    fun allIndexOff(value: T) = (0..<width()).flatMap { x ->
+        (0..<height()).mapNotNull { y ->
+            if (get(x by y) == value) x by y else null
+        }
+    }
+
+    operator fun get(p: Point<Int>) = data[p.x][p.y]
+
+    operator fun set(p: Point<Int>, value: T) {
+        data[p.x][p.y] = value
+    }
+
+    override fun toString() = buildString {
+        for (y in 0..<height()) {
+            for (x in 0..<width()) {
+                append(get(x by y))
+            }
+            appendLine()
+        }
+    }
+
+
+}

src/main/kotlin/nl/tiemenschut/aoc/lib/util/grid/GridParser.kt

@@ -0,0 +1,19 @@
+package nl.tiemenschut.aoc.lib.util.grid
+
+import nl.tiemenschut.aoc.lib.dsl.parser.InputParser
+
+object CharGridParser : InputParser<Grid<Char>> {
+    override fun parse(input: String): Grid<Char> {
+        val lines = input.split("\n")
+
+        val data = List(lines[0].length) { MutableList(lines.size) { ' ' } }.also { grid ->
+            for (y in lines.indices) {
+                for (x in lines[y].indices) {
+                    grid[x][y] = lines[y][x]
+                }
+            }
+        }
+
+        return Grid(data)
+    }
+}