装饰器与函数的多层嵌套

Posted 2020-06-13

# coding: utf-8
def login(func):
    print("the first level")
    def inner1(*args):
        print("the second level")
        def inner2(*args):
            print("the third level")
            def inner3(*args):
                print("the forth level")
                func(*args)
            func(*args)
            return inner3
        func(*args)
        return inner2
    return inner1

@login
def tv(name,password):
    print("Welcome [%s] [%s] to TV page" % (name,password) )



print(tv)
tv = login(tv)
print(tv)

tv = tv("zhou","123")
print(tv)
tv = tv("zhouding","123456")
print(tv)
tv("zhoudingzhao","12345678")

　　执行结果如下：

the first level
<function login.<locals>.inner1 at 0x02D94150>
the first level
<function login.<locals>.inner1 at 0x02D94198>
the second level
the second level
Welcome [zhou] [123] to TV page
<function login.<locals>.inner1.<locals>.inner2 at 0x02D941E0>
the third level
the second level
Welcome [zhouding] [123456] to TV page
<function login.<locals>.inner1.<locals>.inner2.<locals>.inner3 at 0x02D94198>
the forth level
the second level
Welcome [zhoudingzhao] [12345678] to TV page

 

@login 的作用：相当于 tv = login(tv) ,把 tv 函数的内存地址传给login的参数 func ，login 函数返回其内部函数 inner1 的内存地址 给 tv 。当执行 tv 函数 的时候，其实是执行了login的 inner1 函数。