44 lines
1.2 KiB
Python
44 lines
1.2 KiB
Python
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def apply_async(func, args, *, callback):
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result = func(*args)
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callback(result)
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def print_result(result):
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print(result)
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def add(x, y):
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return x + y
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# 如果只是简单的调用回调函数，那直接用就可以了
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apply_async(add, (1, 2), callback=print_result)
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apply_async(add, ('hello', 'world'), callback=print_result)
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# 但是，如果我想要知道这个函数被调用了几次，携带这些保存的信息返回，可以这样改写：
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def make_handler():
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sequence = 0
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def handler(result):
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nonlocal sequence
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sequence += 1
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print('[{}] Got: {}'.format(sequence, result))
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return handler
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handler = make_handler()
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apply_async(add, (1, 2), callback=handler)
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apply_async(add, (1, 2), callback=handler)
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# 当然我们也能用协程去搞定它：
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# 协程的复习在10.1中，单步调试你就看懂了
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def make_handler_v2():
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sequence = 0
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while True:
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result = yield
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sequence += 1
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print('[{}] Got: {}'.format(sequence, result))
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handler = make_handler_v2()
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next(handler)
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apply_async(add, (1, 2), callback=handler.send)
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apply_async(add, (1, 2), callback=handler.send)
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apply_async(add, (1, 2), callback=handler.send)
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