使用Asyncio的Coroutine来实现一个有限状态机

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import asyncio
import datetime
import time
from random import randint


@asyncio.coroutine
def StartState():
    print("Start State called \n")
    input_value = randint(0, 1)
    time.sleep(1)
    if (input_value == 0):
        result = yield from State2(input_value)
    else:
        result = yield from State1(input_value)
    print("Resume of the Transition: \nStart State calling " \
          + result)

@asyncio.coroutine
def State1(transition_value):
    outputValue = str(("State 1 with transition value = %s \n" \
                       %(transition_value)))
    input_value = randint(0, 1)
    time.sleep(1)
    print("...Evaluating....")
    if (input_value == 0):
        result = yield from State3(input_value)
    else:
        result = yield from State2(input_value)

    result = "State 1 calling " + result
    return (outputValue + str(result))

@asyncio.coroutine
def State2(transition_value):
    outputValue = str(("State 2 with transition value = %s \n" \
                       %(transition_value)))
    input_value = randint(0, 1)
    time.sleep(1)
    print("...Evaluating....")
    if (input_value == 0):
        result = yield from State1(input_value)
    else:
        result = yield from State3(input_value)

    result = "State 2 calling " + result
    return (outputValue + str(result))

@asyncio.coroutine
def State3(transition_value):
    outputValue = str(("State 3 with transition value = %s \n" \
                       %(transition_value)))
    input_value = randint(0, 1)
    time.sleep(1)
    print("...Evaluating....")
    if (input_value == 0):
        result = yield from State1(input_value)
    else:
        result = yield from EndState(input_value)

    result = "State 2 calling " + result
    return (outputValue + str(result))

@asyncio.coroutine
def EndState(transition_value):
    outputValue = str(("End State with transition value = %s \n" \
                       %(transition_value)))
    print("...Stop Computation...")
    return (outputValue)


if __name__ == "__main__":
    print("Finite State Machine simulation With Asyncio Coroutine")
    loop = asyncio.get_event_loop()
    loop.run_until_complete(StartState())