Python装饰器（decorator）不过如此，是我想多了

@makebold@makeitalicdefsay():return"Hello"print(say()))

<b><i>Hello</i></b>

def decorator(fun):    # 装饰器中的代码

from functools import wraps
defmakebold(fn):    @wraps(fn)defmakebold_wrapped(*args, **kwargs):return"<b>" + fn(*args, **kwargs) + "</b>"return makebold_wrapped
defmakeitalic(fn):    @wraps(fn)defmakeitalic_wrapped(*args, **kwargs):return"<i>" + fn(*args, **kwargs) + "</i>"return makeitalic_wrapped

@makeitalic@makebolddefsay():return"Hello"print(say.__name__)   # 输出函数名

makebold_wrapped

defshout(word="yes"):return word.capitalize()# 输出：Yesprint(shout())# 将shout函数赋给另一个变量，这里并没有使用圆括号，# 所以不是调用函数，而是将函数赋给另一个变量，也就是为函数起一个别名scream = shout
# 可以用scream调用shout函数# 输出：Yesprint(scream())
# 目前，同一个函数，有两个引用：scream和shout，可以使用del删除一个引用del shouttry:# 该引用删除后，就不能通过该引用调用函数了    print(shout())except NameError as e:    print(e)
# 仍然可以通过另外一个引用调用函数# 输出：Yesprint(scream())

deftalk():# 内嵌函数defwhisper(word="YES"):return word.lower()+"..."
# 调用内嵌函数    print(whisper())
# 调用talk，whisper函数在talk内部被调用# 输出：yes...talk()
try:# 但whisper函数在talk函数外部并不可见，所以调用会哦抛出异常    print(whisper())except NameError as e:    print(e)

defgetTalk(kind="shout"):
#  定义第1个内嵌函数defshout(word="yes"):return word.capitalize()+"!"# 定义第2个内嵌函数defwhisper(word="yes") :return word.lower()+"..."
# 根据参数值返回特定的函数if kind == "shout":# 这里没有使用一对圆括号，所以不是调用函数，而是返回函数本身return shoutelse:return whisper

# talk是函数本身，并没有被调用talk = getTalk()
# 输出函数本身# 输出：<function getTalk.<locals>.shout at 0x7f93a00475e0>print(talk)
# 调用talk函数（其实是shout函数）print(talk())#outputs : Yes!
# 调用whisper函数print(getTalk("whisper")())

def doSomethingBefore(func):print("I do something before then I call the function you gave me")print(func())
doSomethingBefore(talk)

# 装饰器函数，参数是另一个函数（被装饰的函数）defmy_shiny_new_decorator(a_function_to_decorate):# 装饰器的内嵌函数，用来包装被修饰的函数defthe_wrapper_around_the_original_function():# 在调用被修饰函数之前输出一行文本        print("Before the function runs")
# 调用被装饰函数        a_function_to_decorate()
# 在调用被修饰函数之后输出一行文本        print("After the function runs")
# 返回包装函数return the_wrapper_around_the_original_function
# 这个函数将被my_shiny_new_decorator函数修饰defa_stand_alone_function():    print("I am a stand alone function, don't you dare modify me")
# 调用函数a_stand_alone_function()
# 修饰a_stand_alone_function函数a_stand_alone_function_decorated = my_shiny_new_decorator(a_stand_alone_function)a_stand_alone_function_decorated()

I am a stand alone function, don'tyoudaremodifymeBeforethefunctionrunsIamastandalonefunction, don'tyoudaremodifymeAfterthefunctionruns

@my_shiny_new_decoratordefa_stand_alone_function():    print("I am a stand alone function, don't you dare modify me")