# 知識儲備 __call__ 方法,對象加括號就默認執行__call__()

# class Foo:
#     def __call__(self, *args, **kwargs):
#         print(self)
#         print(args)
#         print(kwargs)
#
# obj = Foo()
# obj(1,2,3,a=1,b=2,c=3)

# 元類內部也應有一個__call__方法，會在類實例化時觸發
# Foo(1,2,x=1)  => Foo.__call__(Foo,1,2,x=1)


class Mymeta(type):
    def __init__(self,class_name,class_bases,class_dic):
 
        if not class_name.istitle():
            raise TypeError(‘類名的首字母必須大寫！‘)
        if ‘__doc__‘ not in class_dic or not class_dic[‘__doc__‘].strip():
            raise TypeError(‘必須有註釋，且註釋不能為空！‘)
        super(Mymeta,self).__init__(class_name,class_bases,class_dic)

    def __call__(self, *args, **kwargs):
 
        # 第一件事：先造一個空對象obj
        obj = object.__new__(self)
        # 第二件事：初始化obj
        self.__init__(obj, *args, **kwargs)
        # 第三件事：返回obj
        return obj


class Chinese(object,metaclass=Mymeta):
    ‘‘‘
    中文類
    ‘‘‘
    country = ‘China‘

    def __init__(self,name,age):
        self.name = name
        self.age = age
 

    def talk(self):
        print(‘%s is talking‘ % self.name)

obj = Chinese(‘egon‘,age=18)
print(obj.__dict__)

自定義元類控制類的實例化行為