added turtleInstructionParser

src/lib/turtle/TurtleInstructionParser.hx

@@ -0,0 +1,126 @@
+package lib.turtle;
+
+// Check usage of NativeStringTools
+// here https://api.haxe.org/lua/NativeStringTools.html
+// and here http://lua-users.org/wiki/StringLibraryTutorial
+
+import kernel.turtle.Types.TurtleSlot;
+import kernel.turtle.Turtle;
+import lua.NativeStringTools;
+
+using tink.CoreApi;
+
+
+/**
+	Save a set of turtle instructions to a string and execute them.
+**/
+class TurtleInstructionParser {
+
+	public function new() {
+
+	}
+
+	public function encode(instructions: Array<TurtleInstruction>): String {
+		var s = "";
+
+		var times = 0;
+		var lastInstruction: TurtleInstruction = null;
+
+		for (inst in instructions){
+			if (inst == lastInstruction){
+				times++;
+				continue;
+			}
+
+			if (lastInstruction != null){
+				var encoded = encodeInstruction(lastInstruction);
+				s = s + '${times + 1}$encoded';
+			}
+
+			times = 0;
+			lastInstruction = inst;
+		}
+
+		var encoded = encodeInstruction(lastInstruction);
+		s = s + '${times + 1}$encoded';
+
+		return s;
+	}
+
+	private function encodeInstruction(inst: TurtleInstruction): String {
+		for (k => v in cmdMap){
+			if (v == inst){
+				return k;
+			}
+		}
+
+		switch inst {
+			case Select(slot):
+				return "m" + encodeSlot(slot);
+			default:
+				return "";
+		}
+
+		return "";
+	}
+
+	private function encodeSlot(slot: TurtleSlot): String {
+		return String.fromCharCode(slot + 97);
+	}
+
+	public function parse(instructionsString: String): Array<TurtleInstruction> {
+		var rtn: Array<TurtleInstruction> = [];
+		var mfunc = NativeStringTools.gmatch(instructionsString,"%d+%D+");
+
+		while(true){
+			var found = mfunc();
+
+			if (found == null) {
+				break;
+			}
+
+			var times = Std.parseInt(NativeStringTools.match(found, "%d+"));
+			var command = NativeStringTools.match(found, "%D+");
+
+			var cmd = cmdMap.get(command);
+			if (cmd != null){
+				rtn = rtn.concat([for (i in 0...times) cmd]);
+			}
+
+			switch command.charAt(0) {
+				case "m": // select
+					var slot = parseSlot(command.charAt(1));
+					rtn = rtn.concat([for (i in 0...times) Select(slot)]);
+			}
+		}
+
+		return rtn;
+	}
+
+	private static function parseSlot(slot: String): TurtleSlot {
+		var slot = slot.charCodeAt(0) - 97;
+
+		if (slot < 0 || slot > Turtle.MAX_SLOTS) {
+			// TODO: better error handling
+			throw new Error("Invalid slot: " + slot);
+		}
+
+		return slot;
+	}
+
+	private var cmdMap:Map<String,TurtleInstruction> = [
+		"a" => Forward,
+		"b" => Back,
+		"c" => TurnLeft,
+		"d" => TurnRight,
+		"e" => Up,
+		"f" => Down,
+		"g" => Dig(Front),
+		"h" => Dig(Up),
+		"i" => Dig(Down),
+		"j" => Place(Front),
+		"k" => Place(Up),
+		"l" => Place(Down),
+	];
+
+}