class StateMachine:
def __init__(self):
self.handlers = {} # 狀態轉移函數字典
self.startState = None # 初始狀態
self.endState = [] # 最終狀態集合
# 參數name爲狀態名,handler爲狀態轉移函數,end_state表明是否爲最終狀態
def add_state(self, name, handler, end_state=0):
name = name.upper()
self.handlers[name] = handler
if end_state:
self.endState.append(name)
def set_start(self, name):
self.startState = name.upper()
def run(self, cargo):
try:
handler = self.handlers[self.startState]
except:
raise Exception("must call .set_start() before .run()")
if not self.endState:
raise Exception("at least one state must be an end_state")
while True:
(newState, cargo) = handler(cargo)
if newState.upper() in self.endState:
print("reached ", newState)
break
else:
handler = self.handlers[newState.upper()]
# 有限狀態集合
positive_adjectives = ["great", "super", "fun", "entertaining", "easy"]
negative_adjectives = ["boring", "difficult", "ugly", "bad"]
# 自定義狀態轉變函數
def start_transitions(txt):
# 用指定分隔符對字符串進行切片,默認爲空格分割,參數num指定分割次數
# 將"Python is XXX"語句分割爲"Python"和之後的"is XXX"
splitted_txt = txt.split(None, 1)
word, txt = splitted_txt if len(splitted_txt) > 1 else (txt, "")
if word == "Python":
newState = "Python_state" # 如果第一個詞是Python則可轉換到"Python狀態"
else:
newState = "error_state" # 如果第一個詞不是Python則進入終止狀態
return (newState, txt) # 返回新狀態和餘下的語句txt
def python_state_transitions(txt):
splitted_txt = txt.split(None, 1)
word, txt = splitted_txt if len(splitted_txt) > 1 else (txt, "")
if word == "is":
newState = "is_state"
else:
newState = "error_state"
return (newState, txt)
def is_state_transitions(txt):
splitted_txt = txt.split(None, 1)
word, txt = splitted_txt if len(splitted_txt) > 1 else (txt, "")
if word == "not":
newState = "not_state"
elif word in positive_adjectives:
newState = "pos_state"
elif word in negative_adjectives:
newState = "neg_state"
else:
newState = "error_state"
return (newState, txt)
def not_state_transitions(txt):
splitted_txt = txt.split(None, 1)
word, txt = splitted_txt if len(splitted_txt) > 1 else (txt, "")
if word in positive_adjectives:
newState = "neg_state"
elif word in negative_adjectives:
newState = "pos_state"
else:
newState = "error_state"
return (newState, txt)
if __name__ == "__main__":
m = StateMachine()
m.add_state("Start", start_transitions) # 添加初始狀態
m.add_state("Python_state", python_state_transitions)
m.add_state("is_state", is_state_transitions)
m.add_state("not_state", not_state_transitions)
m.add_state("neg_state", None, end_state=1) # 添加最終狀態
m.add_state("pos_state", None, end_state=1)
m.add_state("error_state", None, end_state=1)
m.set_start("Start") # 設置開始狀態
m.run("Python is great")
m.run("Python is not fun")
m.run("Perl is ugly")
m.run("Pythoniseasy")
Python 狀態機
發表評論
所有評論
還沒有人評論,想成為第一個評論的人麼? 請在上方評論欄輸入並且點擊發布.