python状态机transitions库详解

pip install transitions

from transitions import Machine

class Number(object):
    pass
    
number = Number()
machine = Machine(model=number)

'''
构造简单的state
'''
# 只指定名字
zero = '0'

# 通过State()
from transitions import State
one = State('1')

# 构造字典
two = {'name':'2'}

'''
构造复杂的State
'''
class Number(object):
    def hello(self):
        print('hello')
    pass

zero = '0'


from transitions import State
one = State('1', on_enter=['hello'], on_exit=['hello'])


two = {'name':'2', 'on_enter':['hello'], 'on_exit':['hello']}

'''
添加state
'''
# 逐个
machine.add_states(zero)

# 一起添加
machine.add_states([one, two])

machine.add_transition('zero_to_one', source='0', dest='1')    # 有效
machine.add_transition('zero_to_one', source='1', dest='2')    # 无效

states = [
    {'name':'0'},
    {'name':'1'},
    {'name':'2', 'on_enter':['hello'], 'on_exit':['hello']},
]

# way1
transitions = [
    { 'trigger': 'zero_to_one', 'source': '0', 'dest': '1' },
    { 'trigger': 'zero_to_two', 'source': '0', 'dest': '2' },
    { 'trigger': 'one_to_two', 'source': '1', 'dest': '2' },
    { 'trigger': 'any_to_zero', 'source': '*', 'dest': '0' },   # 任意前状态 '*'
]

# way2
transitions = [
    ['zero_to_one', '0', '1' ],
    ['one_to_two', '1', '2' ],
    ['any_to_zero', '*', '0' ],    # 任意前状态 '*'
]

from transitions import Machine

class Number(object):
    def hello(self):
        print('hello')
    pass
    
number = Number()
machine = Machine(
	model=number, 
	states=states, 
	initial=states[0]['name'],
	transitions=transitions
)

now_state = number.state
print(now_state)

number.is_0()

number.to_2()

machine.get_triggers('0')
# ['to_0', 'to_1', 'to_2', 'zero_to_one', 'any_to_zero']

# way 1
number.zero_to_one()

# way 2
number.trigger('zero_to_one')

from transitions import Machine

class Number(object):
    def hello(self):
        print('hello')
    pass
number = Number()

states = [
    {'name':'0', 'on_enter':['hello']},
    {'name':'1'},
    {'name':'2'},
]
transitions = [
    { 'trigger': 'zero_to_one', 'source': '0', 'dest': '1' },
    { 'trigger': 'zero_to_two', 'source': '0', 'dest': '2' },
    { 'trigger': 'one_to_two', 'source': '1', 'dest': '2' },
    { 'trigger': 'any_to_zero', 'source': '*', 'dest': '0' },   # 任意前状态 '*'
]
Machine(model=number, states=states, initial=states[0]['name'],transitions=transitions)

init_state = number.state
print(init_state)				

number.zero_to_one()
print(number.state)

number.any_to_zero()			
print(number.state)
'''
0		# 第一次不会调用，因为已经进入了
1
hello	# 再进来时才调用
0
'''