Refactor parser for some added flexibility.

main.ts

@@ -1,75 +1,64 @@
-import User from "./User.ts";
-import Scene from "./Scene.ts";
+import Interpreter from "./Interpreter.ts";
 import Player from "./Player.ts";
+import Scene from "./Scene.ts";
+import User from "./User.ts";
 import { hall } from "./data/data.ts";
-import parseCommand from "./parseCommand.ts";
 
 async function main() {
-	const user = new User();
-	const scene = new Scene(hall);
-	const player = new Player();
-	const question = "";
-	let running = true;
-	let statement = "";
+	const user = new User(); // for communication with the user
+	const scene = new Scene(hall); // the room that player is in.
+	const player = new Player(); // the players current state
+	let running = true; // running flag for the game loop. Stops on false.
+	let statement = ""; // holds a statement for the user.
 
 	while (running) {
-		const prompts = `${statement}${question}`;
+		const prompts = `${statement}\n`;
 		const answer = await user.ask(prompts);
 
-		const { action, target } = parseCommand(answer);
-
-		statement = "";
-
-		switch (action) {
+		// User commands that are not player moves, but are about running the
+		// game itself (e.g. loading, saving, quitting) may need to get handled
+		// here.
+		switch (answer) {
+			// kills the game loop.
 			case "quit":
 				running = quit(user);
-				break;
-
-			case "look":
-				await scene.look();
-				break;
-
-			case "take":
-				await pickUpItem(user, scene, player, target);
-				break;
-
-			case "inventory":
-				await player.look();
+				statement = "";
 				break;
 
 			default:
-				statement = "\nI didn't understand that.\n";
+				// Game moves require more complicated commands, this switch is
+				// not adequate to handle them. Here we will pass them off to
+				// other functions to parse.
+				statement = interpretUserCommand(player, scene, answer);
 				break;
 		}
 	}
 }
 
+// Takes player and scene state and a command. Tries to figure out what the
+// user is trying to do and, if it can, it executes the command.
+function interpretUserCommand(
+	player: Player,
+	scene: Scene,
+	command: string
+): string {
+	const interpreter = new Interpreter(player, scene, command);
+	interpreter.interpret();
+	return interpreter.execute();
+}
+
+// When it returns false, the loop should be stopped. When it returns true,
+// the loop should continue.
 function quit(user: User): boolean {
 	const confirmQuit = user.ask("Are you sure you want to quit?\n");
 
-	if (confirmQuit[0] === "y") {
+	// Anything that starts with a "y" or a "Y" is considered an affirmative
+	// response.
+	if (confirmQuit[0].toLocaleLowerCase() === "y") {
 		return false;
 	}
 
 	return true;
 }
 
-async function pickUpItem(
-	user: User,
-	scene: Scene,
-	player: Player,
-	target?: string
-) {
-	if (!target) {
-		await user.tell("What do you want me to take?");
-		return;
-	}
-
-	const item = await scene.take(target);
-
-	if (item !== null) {
-		player.drop(item);
-	}
-}
-
 main();