Add nim stub to main repo

nim/game_stub.py

@@ -0,0 +1,34 @@
+class NimGameStub:
+    """A stub is a minimal version of a class which stands in for the 
+    real class, which hasn't yet been written. The stub has all the correct 
+    methods, and their inputs and outputs are the right kind of thing, 
+    but it doesn't really do anything. 
+    """
+    def get_initial_state(self):
+        return {
+            "board": [1, 3, 5, 7],
+            "first_player": True
+        }
+
+    def get_next_state(self, state, action):
+        next_state = {
+            "board": state["board"].copy(),
+            "first_player": not state["first_player"],
+        }
+        return next_state
+
+    def get_actions(self, state):
+        return [
+            (0, 0), 
+            (1, 0), (1, 1),
+            (2, 0), (2, 1), (2, 2), (3, 0), (3, 1), (3, 2), (3, 3),
+        ]
+
+    def get_reward(self, state):
+        return 0
+
+    def is_over(self, state):
+        return False
+
+    def get_objective(self, state):
+        return max if state["first_player"] else min

nim/player.py

@@ -0,0 +1,35 @@
+from nim.game_stub import NimGameStub
+from strategy.lookahead_strategy import LookaheadStrategy
+
+class HumanNimPlayer:
+    def __init__(self, name):
+        self.name = name
+        self.game = NimGameStub()
+
+    def choose_action(self, state):
+        actions = self.game.get_actions(state)
+        for i, action in enumerate(actions):
+            row, lines_to_remove = action
+            print(f"{i}. Remove {lines_to_remove} from row {row}.")
+        choice = self.get_int(len(actions))
+        return actions[choice]
+
+    def get_int(self, maximum):
+        while True:
+            response = input("> ")
+            if response.isdigit():
+                value = int(response)
+                if value < maximum:
+                    return value
+            print("Invalid input.")
+
+class ComputerNimPlayer:
+    def __init__(self, name):
+        self.name = name
+        self.strategy = LookaheadStrategy(NimGameStub(), max_depth=3, deterministic=False)
+
+    def choose_action(self, state):
+        action = self.strategy.choose_action(state)
+        row, lines_to_remove = action
+        print(f"{self.name} removes {lines_to_remove} from row {row}")
+        return action

nim/view.py

@@ -0,0 +1,32 @@
+from nim.game_stub import NimGameStub
+
+class NimView:
+    def __init__(self, player0, player1):
+        self.players = [player0, player1]
+        self.game = NimGameStub()
+
+    def greet(self):
+        print(f"{self.players[0].name} and {self.players[1].name}, welcome to Nim.")
+    
+    def show_board(self, state):
+        for lines_in_row in state["board"]:
+            print("| " * lines_in_row)
+
+    def get_action(self, state):
+        self.show_board(state)
+        player = self.get_current_player(state)
+        return player.choose_action(state)
+
+    def get_current_player(self, state):
+        if state["first_player"]:
+            return self.players[0]
+        else:
+            return self.players[1]
+
+    def conclude(self, state):
+        self.show_board(state)
+        if self.game.get_reward(state) > 0:
+            winner = self.players[0]
+        else:
+            winner = self.players[1]
+        print(f"Congratulations, {winner.name}!")

play_nim.py

@@ -0,0 +1,15 @@
+from nim.game_stub import NimGameStub
+from nim.view import NimView
+from nim.player import HumanNimPlayer, ComputerNimPlayer
+
+player0 = HumanNimPlayer(input("What's your name? "))
+player1 = ComputerNimPlayer("Robot")
+view = NimView(player0, player1)
+game = NimGameStub()
+
+view.greet()
+state = game.get_initial_state()
+while not game.is_over(state):
+    action = view.get_action(state)
+    state = game.get_next_state(state, action)
+view.conclude(state)