python - TypeError - 未绑定(bind)方法 ToTransition() 必须以 FSM 实例作为第一个参数调用(取而代之的是 str 实例)

Question

我有一个有限状态机，它应该随机选择一个状态进入，但是我收到以下类型错误；

unbound method ToTransition() must be called with FSM instance as first argument (got str instance instead)

我不确定为什么会这样。启动时，它可以调用第一个状态，但随后失败。任何建议将不胜感激。

from random import randint
from time import clock

##========================================
##TRANSITIONS

class Transition(object):
def __init__(self, toState):
    self.toState = toState

def Execute(self):
    print ("Transitioning...")

##=======================================
##STATES

class State(object):
    def __init__(self, FMS):
        self.FSM = FSM
        self.timer = 0
        self.startTime = 0

    def Enter(self):
        self.timer = randint(0,5)
        self.startTime = int(clock())

    def Execute(self):
        pass

    def Exit(self):
        pass

class CleanDishes(State):
    def __init__(self, FSM):
        super(CleanDishes, self).__init__(FSM)

    def Enter(self):
        print ("Preparing to clean dishes")
        super(CleanDishes, self).Enter()

    def Execute(self):
        print ("Cleaning Dishes.")
        if(self.startTime + self.timer <= clock()):
            if not(randint(1,3) %2):
                self.FSM.ToTransition("toVacuum")
            else:
                self.FSM.ToTransition("toSleep")

    def Exit(self):
        print ("Finished the Dishes.")

class Vacuum(State):
    def __init__(self, FSM):
        super(Vacuum, self).__init__(FSM)

    def Enter(self):
        print ("Preparing to Vacumm")
        super(Vacuum, self).Enter()

    def Execute(self):
        print ("Vacuuming.")
        if(self.startTime + self.timer <= clock()):
            if not(randint(1, 3) %2):
                self.FSM.ToTransition('toSleep')
            else:
                self.FSM.ToTransition('toCleanDishes')

    def Exit(self):
        print ("Finished Vacuuming.")

class Sleep(State):
    def __init__(self, FSM):
        super(Sleep, self).__init__(FSM)

    def Enter(self):
        print ("falling asleep")
        super(Sleep, self).Enter()

    def Execute(self):
        print ("Sleeping.")
        if(self.startTime + self.timer <= clock()):
            if not(randint(1,3) %2):
                self.FSM.ToTransition("toVacuum")
            else:
                self.FSM.ToTransition("toCleanDishes")

    def Exit(self):
        print ("Waking Up.")

##======================================
##FSM

class FSM(object):
    def __init__(self, character):
        self.char = character
        self.states = {}
        self.transitions = {}
        self.curState = None
        self.prevState = None
        self.trans = None

    def AddTransition(self, transName, transition):
        self.transitions[transName] = transition

    def AddState(self, stateName, state):
        self.states[stateName] = state

    def SetState(self, stateName):
        self.prevState = self.curState
        self.curState = self.states[stateName]

    def ToTransition(self, toTrans):
        self.trans = self.transitions[toTrans]

    def Execute(self):
        if(self.trans):
            self.curState.Exit()
            self.trans.Execute()
            self.SetState(self.trans.toState)
            self.curState.Enter()
            self.trans = None
        self.curState.Execute()

##===================================
##IMPLEMENTATION

Char = type("Char", (object,), {})

class RobotMaid(Char):
    def __init__(self):
        self.FSM = FSM(self)

        ##STATES
        self.FSM.AddState("Sleep", Sleep(self.FSM))
        self.FSM.AddState("CleanDishes", CleanDishes(self.FSM))
        self.FSM.AddState("Vacuum", Vacuum(self.FSM))

        ##TRANSISITONS
        self.FSM.AddTransition("toSleep", Transition(Sleep))
        self.FSM.AddTransition("toVacuum", Transition(Vacuum))
        self.FSM.AddTransition("toCleanDishes", Transition(CleanDishes))

        self.FSM.SetState("Vacuum")

    def Execute(self):
        self.FSM.Execute()

if __name__ == '__main__':
    r = RobotMaid()
    for i in range(20):
        startTime = clock()
        timeInterval = 1
        while(startTime + timeInterval > clock()):
            pass
        r.Execute()

Answer 1

这里:

class State(object):
    def __init__(self, FMS):
        self.FSM = FSM

参数名称是“FMS”，但您将 self.FSM 设置为 FSM，然后解析为(全局)FSM类。

如果您遵循 Python 命名约定(CamelCase 中的类名称，all_lower 中的变量和方法名称)或至少遵循一些一致的命名约定，即您不对类和类使用完全相同的名称，则不会发生这种情况实例...