Python简单装饰器问题

Question

def my_decorator(some_function):
        print("Something is happening before some_function() is called.")
        some_function()
        print("Something is happening after some_function() is called.")

def just_some_function():
    print("Wheee!")

just_some_function = my_decorator(just_some_function)
just_some_function()

TypeError: 'NoneType' object is not callable 

我真的不明白，为什么这不起作用？

根据我的理解，

just_some_function基本上应该成为：

just_some_function():
        print("Something is happening before some_function() is called.")  
        print("Wheee!")  
        print("Something is happening after some_function() is called.")  

但原始函数需要一个包装函数才能工作，例如：

def my_decorator(some_function):
    def wrapper():
        print("Something is happening before some_function() is called.")
        some_function()
        print("Something is happening after some_function() is called.")
    return wrapper

为什么呢？有人可以解释它背后的逻辑吗？

Answer 1

装饰者应该创造新的功能＆＃34;替换＆＃34;原始功能。

def my_decorator(some_function):
        print("Something is happening before some_function() is called.")
        some_function()
        print("Something is happening after some_function() is called.")

这个＆＃34;装饰＆＃34; return None - ＆gt; just_some_function =无 - ＆gt; TypeError：＆＃39; NoneType＆＃39;对象不可调用

def my_decorator(some_function):
    def wrapper():
        print("Something is happening before some_function() is called.")
        some_function()
        print("Something is happening after some_function() is called.")
    return wrapper

这个＆＃34;装饰＆＃34;返回包装器 - ＆gt; just_some_function = wrapper - ＆gt;它的工作。

您也可以查看。试试print(just_some_function.__name__) - ＆gt; ＆＃34;包装＆＃34;