reeborg.py

# https://reeborg.ca/reeborg.html

DIR_PATTERNS = [
    (0, 1),     # ↑
    (-1, 0),    # ←    
    (0, -1),    # ↓
    (1, 0)      # →
]
dir_idx = None
def face_north():
    """
    Turn left until the roeborg faces north,
    and initialize the direction index.
    """
    while not is_facing_north():
        turn_left()
    global dir_idx
    dir_idx = 0

def turn_left_dir():
    """
    Turn left and update the direction
    """
    global dir_idx
    dir_idx = (dir_idx + 1) % len(DIR_PATTERNS)      
    turn_left()

def turn_right_dir():
    for _ in range(3):
        turn_left_dir()
        
# Set initial loc
loc_h, loc_v = 0,0

# List of direction&location dictionary.
history = []
# history = [(0, -2, 3), (0, -2, 4) ...]
def move_with_record():
    """
    Move while recording pos and direction.
    """
    global loc_h, loc_v, history
    
    dir_v, dir_h = DIR_PATTERNS[dir_idx]    
    loc_h += dir_h
    loc_v += dir_v
    history.append((dir_idx, loc_h, loc_v))
    print(history)
    
    move()

# Face north and set initial direction.
face_north()
dir_h, dir_v = DIR_PATTERNS[dir_idx]

while not at_goal():       
    if right_is_clear():
        turn_right_dir()
        move_with_record()
    elif front_is_clear():
        move_with_record()
    else:
        turn_left_dir()
    
    # If noticed repeating,
    if history and history[-1] in history[:-1]:
        if front_is_clear():
            move_with_record()
        elif not right_is_clear():
            turn_left_dir()
            move_with_record()            
        else:
            turn_right_dir()    
        history = []