Question

我有类别：

class Metaclass(type):
    def __new__(self, name, bases, attrs):

        for k, v in attrs.iteritems():
            if isinstance(v, types.FunctionType):
               attrs[k] = self.decorator(v)
        return super(MetaClass, self).__new__(self, name, bases, attrs)

    @classmethod
    def decorator(cls, func):
        def wrapper(*args, **kwargs):
            print(func.__name__)

但我不能func.__class__.__name__打印元类。我希望获得func.__name__课程的名称。显然它不可能是python 2.7（？）我可以将classname作为参数传递吗？调用这个装饰器的方法？即如果testmethod调用metaclass装饰器并将Testclass作为参数传递。所以，如果我知道func.__name__来自特定类，那就做特定的事情。

Answer 1

您忘了从装饰器返回包装器。它应该是：

class Metaclass(type):
    def __new__(self, name, bases, attrs):

        for k, v in attrs.iteritems():
            if isinstance(v, types.FunctionType):
               attrs[k] = self.decorator(v)
        return super(Metaclass, self).__new__(self, name, bases, attrs)

    @classmethod
    def decorator(cls, func):
        def wrapper(*args, **kwargs):
            print(func.__name__)
        return wrapper

您现在可以使用元类：

>>> class TestClass(object):
    __metaclass__ = Metaclass
    def foo(self):
        return "bar"

>>> t = TestClass()
>>> x = t.foo()
foo
>>> print x
None

该方法已被包装器正确替换。

在您之前（现已删除）的问题中，您要求 print＆＃34;此方法来自Testclass＆＃34; 。您只需将类名传递给装饰器：

class Metaclass(type):
    def __new__(self, name, bases, attrs):

        for k, v in attrs.iteritems():
            if isinstance(v, types.FunctionType):
               attrs[k] = self.decorator(v, name)
        return super(Metaclass, self).__new__(self, name, bases, attrs)

    @classmethod
    def decorator(cls, func, name):
        def wrapper(self, *args, **kwargs):
            print "%s defined in %s called from %s instance" % (func.__name__,
                name, self.__class__.__name__)
            return func(self, *args, **kwargs)
        return wrapper

您现在获得：

>>> class TestClass(object):
    __metaclass__ = Metaclass
    def foo(self):
        return "bar"


>>> t = TestClass()
>>> x = t.foo()
foo defined in TestClass called from TestClass instance
>>> print x
bar

Metaclass将classname作为参数传递

1 个答案: