--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/code/grid.lm	Sun Jul 27 01:36:39 2014 -0700
@@ -0,0 +1,68 @@
+#{
+	import: [
+		length
+		reverse
+		split:at
+		map
+		fold:with
+		filter
+		flatten
+	] from: (module: "ll.lm")
+		
+	import: [
+		makeTree:size
+		makeTree
+		get:fromTree:size
+		get:fromTree
+		treeMap:size
+		treeMap
+		tree:size:update:with
+		tree:update:with
+		tree:set:to
+	] from: (module: "tree.lm")
+
+	grid:get <- :grid :pos {
+		x <- pos value
+		y <- pos tail
+		get: x fromTree: (get: y fromTree: grid)
+	}
+	
+	grid:update:with <- :grid :pos :fun {
+		x <- pos value
+		y <- pos tail
+		tree: grid update: y with: :row {
+			tree: row update: x with: fun
+		}
+	}
+	
+	grid:set:to <- :grid :pos :val {
+		grid: grid update: pos with: :el { val }
+	}
+
+	grid:inBounds? <- :grid :pos {
+		x <- pos value
+		y <- pos tail
+		maxY <- grid value
+		maxX <- (get: 0 fromTree: grid) value
+		((x >= 0) + (y >= 0) + (x < maxX) + (y < maxY)) > 0
+	}
+
+	calcPos <- :move from {
+		x <- from value
+		y <- from tail
+		if: move {
+			if: move = 1 {
+				x <- x + 1
+			} else: {
+				if: move = 2 {
+					y <- y + 1
+				} else: {
+					x <- x - 1
+				}
+			}
+		} else: {
+			y <- y - 1
+		}
+		#[x y]
+	}
+}