use std::fmt::{Debug, Formatter, Error}; use std::collections::HashMap; trait HasInventory { fn getInventory<'s>(&'s self) -> &'s mut Inventory; fn addToInventory(&self, item: &Item); fn removeFromInventory(&self, itemName: &str) -> bool; } trait TraversesWorld { fn attemptTraverse(&self, room: &Room, directionStr: &str) -> Result<&Room, &str> { let direction = str_to_direction(directionStr); let maybe_room = room.direction_to_room.get(&direction); match maybe_room { Some(entry) => Ok(entry), //~ ERROR: lifetime may not live long enough _ => Err("Direction does not exist in room.") } } } #[derive(Debug, Eq, PartialEq, Hash)] enum RoomDirection { West, East, North, South, Up, Down, In, Out, None } struct Room { description: String, items: Vec, direction_to_room: HashMap, } impl Room { fn new(description: &'static str) -> Room { Room { description: description.to_string(), items: Vec::new(), direction_to_room: HashMap::new() } } fn add_direction(&mut self, direction: RoomDirection, room: Room) { self.direction_to_room.insert(direction, room); } } struct Item { name: String, } struct Inventory { items: Vec, } impl Inventory { fn new() -> Inventory { Inventory { items: Vec::new() } } } struct Player { name: String, inventory: Inventory, } impl Player { fn new(name: &'static str) -> Player { Player { name: name.to_string(), inventory: Inventory::new() } } } impl TraversesWorld for Player { } impl Debug for Player { fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error> { formatter.write_str("Player{ name:"); formatter.write_str(&self.name); formatter.write_str(" }"); Ok(()) } } fn str_to_direction(to_parse: &str) -> RoomDirection { match to_parse { "w" | "west" => RoomDirection::West, "e" | "east" => RoomDirection::East, "n" | "north" => RoomDirection::North, "s" | "south" => RoomDirection::South, "in" => RoomDirection::In, "out" => RoomDirection::Out, "up" => RoomDirection::Up, "down" => RoomDirection::Down, _ => None } //~^^ ERROR `match` arms have incompatible types } fn main() { let mut player = Player::new("Test player"); let mut room = Room::new("A test room"); println!("Made a player: {:?}", player); println!("Direction parse: {:?}", str_to_direction("east")); match player.attemptTraverse(&room, "west") { Ok(_) => println!("Was able to move west"), Err(msg) => println!("Not able to move west: {}", msg) }; }