greenlet

'''
    利用greenlet实现多个任务的切换

'''
from greenlet import greenlet


def f1():
    print('1')
    gr2.switch()
    print('3')


def f2():
    print('2')
    gr1.switch()
    print('4')


gr1 = greenlet(f1)
gr2 = greenlet(f2)
gr1.switch()