+class GameError(Exception):
+ pass
+
+
+def move_pos(direction, pos_yx):
+ if direction == 'UP':
+ pos_yx[0] -= 1
+ elif direction == 'DOWN':
+ pos_yx[0] += 1
+ elif direction == 'RIGHT':
+ pos_yx[1] += 1
+ elif direction == 'LEFT':
+ pos_yx[1] -= 1
+
+
+class Task:
+
+ def __init__(self, thing, name, args=(), kwargs={}):
+ self.name = name
+ self.thing = thing
+ self.args = args
+ self.kwargs = kwargs
+ self.todo = 1
+
+ def check(self):
+ if self.name == 'move':
+ if len(self.args) > 0:
+ direction = self.args[0]
+ else:
+ direction = self.kwargs['direction']
+ test_pos = self.thing.position[:]
+ move_pos(direction, test_pos)
+ if test_pos[0] < 0 or test_pos[1] < 0 or \
+ test_pos[0] >= self.thing.world.map_size[0] or \
+ test_pos[1] >= self.thing.world.map_size[1]:
+ raise GameError('would move outside map bounds')
+ pos_i = test_pos[0] * self.thing.world.map_size[1] + test_pos[1]
+ map_tile = self.thing.world.map_[pos_i]
+ if map_tile != '.':
+ raise GameError('would move into illegal terrain')
+
+
+class Thing:
+
+ def __init__(self, world, type_, position):
+ self.world = world
+ self.type_ = type_
+ self.position = position
+ self.task = Task(self, 'wait')
+
+ def task_wait(self):
+ pass
+
+ def task_move(self, direction):
+ move_pos(direction, self.position)
+
+ def decide_task(self):
+ if self.position[1] > 1:
+ self.set_task('move', 'LEFT')
+ elif self.position[1] < 3:
+ self.set_task('move', 'RIGHT')
+ else:
+ self.set_task('wait')
+
+ def set_task(self, task, *args, **kwargs):
+ self.task = Task(self, task, args, kwargs)
+ self.task.check()
+
+ def proceed(self, is_AI=True):
+ """Further the thing in its tasks.
+
+ Decrements .task.todo; if it thus falls to <= 0, enacts method whose
+ name is 'task_' + self.task.name and sets .task = None. If is_AI, calls
+ .decide_task to decide a self.task.
+ """
+ self.task.todo -= 1
+ if self.task.todo <= 0:
+ task = getattr(self, 'task_' + self.task.name)
+ task(*self.task.args, **self.task.kwargs)
+ self.task = None
+ if is_AI and self.task is None:
+ self.decide_task()
+
+
+class World:
+
+ def __init__(self):
+ self.turn = 0
+ self.map_size = (5, 5)
+ self.map_ = 'xxxxx' +\
+ 'x...x' +\
+ 'x.X.x' +\
+ 'x...x' +\
+ 'xxxxx'
+ self.things = [
+ Thing(self, 'human', [3, 3]),
+ Thing(self, 'monster', [1, 1])
+ ]
+ self.player_i = 0
+ self.player = self.things[self.player_i]