labydulinthe.py

class Labyrinth:
    MSG_WALL = 'STOMP ! You hit a wall, you stay at your last position'
    MSG_OK = 'OK - your new position is'
    DIRECTIONS = {
        'N' : (0,  1),
        'S' : (0, -1),
        'W' : (-1, 0),
        'E' : (1,  0)
    }
    INVERTED = {
        'N' : 'S',
        'S' : 'N',
        'W' : 'E',
        'E' : 'W'
    }
    CHARS = {
        True  : ' ', # Empty cell
        False : '#', # Wall
        None  : '?'  # Unknown content
    }

    def goto(self, command):
        new_pos = self.pos + self.DIRECTIONS[command]

        # We move
        p.sendline(command)
        result = p.recvline()
        self.grid[new_pos] = result.startswith(self.MSG_OK)
        # If cell is empty, we can move
        if self.grid[new_pos]:
            self.pos += self.DIRECTIONS[command]

        return self.grid[new_pos]

    def discover(self):
        # Simple backtracking
        # self.grid is a wrapper of a 2D list
        for command, direction in self.DIRECTIONS.items():
            new_pos = self.pos + direction

            if self.grid[new_pos] is None:
                if self.goto(command):
                    # If we are able to move, discover the new cell
                    self.discover()
                    # Then, go back
                    self.goto(self.INVERTED[command])