greenlet实现协程

#greenlet
 1 import time
 2 from greenlet import greenlet
 3 # greenlet可以实现一个自行调度的微线程
 4 def work1():
 5     while True:
 6         print("正在执行work1（）")
 7         time.sleep(0.5)#模拟阻塞
 8         # 如果遇到阻塞的情况下，切换到第二个任务
 9         g2.switch()
10 
11 def work2():
12     while True:
13         print("正在执行work2（）")
14         time.sleep(0.5)
15         # 切换到第一个任务
16         g1.switch()
17 
18 if __name__ == ‘__main__‘:
19     # 创建greenlet的对象    greenlet（函数名）
20     g1 = greenlet(work1)
21     g2 = greenlet(work2)
22     g1.switch()