一 协程

def consumer():
    r = ''
    while True:
        n = yield r
        if not n:
            return
        print('[CONSUMER] Consuming %s...' % n)
        r = '200 OK'

def produce(c):
    c.send(None)
    n = 0
    while n < 5:
        n = n + 1
        print('[PRODUCER] Producing %s...' % n)
        r = c.send(n)
        print('[PRODUCER] Consumer return: %s' % r)
    c.close()

c = consumer()
produce(c)

二 子程序调用

def consumer(n):
    if not n:
        return
    print('[CONSUMER] Consuming %s...' % n)
    return '200 OK'

def produce():
    n = 0
    while n < 5:
        n = n + 1
        print('[PRODUCER] Producing %s...' % n)
        r = consumer(n)
        print('[PRODUCER] Consumer return: %s' % r)

produce()

这两种结果一样，协程可以用子程序写，看不出协程有什么特别？