python-在修饰类多方法时丢失了自我

我正试图基于本文实现一种多方法方法。这种方法有两个不同之处：

• 我只需要查看multimethod的第一个参数，因此不需要形成arg类的元组
• 多重方法将存在于类中，它们将不是正则函数

然而，我把我的类弄混了一点，对

self

的调用在调用类方法时丢失了

这是我的密码：

method_registry = {}


class SendMessageMultiMethod(object):
    """
    A class for implementing multimethod functionality
    """
    def __init__(self, name):
        self.name = name
        self.typemap = {}

    def __call__(self, message, extra_payload=None):
        """
        Overrriding method call and dispatching it to an actual method
        based on the supplied message class
        """
        first_arg_type = message.__class__
        function = self.typemap.get(first_arg_type)
        print(
            'Dispatching to function {} with message {} and extra payload {}...'
            .format(function, message, extra_payload)
        )
        return function(message, extra_payload)

    def register(self, type_, function):
        self.typemap[type_] = function


def use_for_type(*types):
    """
    A decorator that registers a method to use with certain types
    """

    def register(method):
        """Creating Multimethod with the method name
        and registering it at at method_registry dict """
        name = method.__name__
        mm = method_registry.get(name)
        if mm is None:
            mm = method_registry[name] = SendMessageMultiMethod(name)
        for type_ in types:
            mm.register(type_, method)
        return mm

    return register


class Sender(object):

    def send_messages(self, messages_list):
        for message in messages_list:
            # this is supposed to fire different send_message() methods
            # for different arg types
            self.send_message(message)

    @use_for_type(int, float)
    def send_message(self, message, *args, **kwargs):
        print('received call for int/float message {} with {}, {}'
              .format(message, args, kwargs))
        print('self is {}'.format(self))

    @use_for_type(bool)
    def send_message(self, message, *args, **kwargs):
        print('received call for bool message {} with {}, {}'
              .format(message, args, kwargs))
        print('self is {}'.format(self))

因此，当我在

Sender

类上调用

send\u messages

方法时，我接收

self

中的参数，而不是

message

变量中的参数。在这里：

sender = Sender()
sender.send_messages([1, 2, True, 5.6])

输出：

Dispatching to function <function Sender.send_message at 0x1013608c8> with message 1 and extra payload None...
received call for int/float message None with (), {}
self is 1
Dispatching to function <function Sender.send_message at 0x1013608c8> with message 2 and extra payload None...
received call for int/float message None with (), {}
self is 2
Dispatching to function <function Sender.send_message at 0x101360950> with message True and extra payload None...
received call for bool message None with (), {}
self is True
Dispatching to function <function Sender.send_message at 0x1013608c8> with message 5.6 and extra payload None...
received call for int/float message None with (), {}
self is 5.6

调度到具有消息1和额外有效负载无的功能。。。
接收到对int/float消息None的调用，带有（），{}
赛尔夫是1
正在调度到具有消息2和额外有效负载无的功能。。。
接收到对int/float消息None的调用，带有（），{}
赛尔夫2岁
正在调度到具有消息True和额外有效负载None的函数。。。
已收到对bool消息None的调用，其中包含（），{}
自我是真实的
发送到带有消息5.6和额外有效负载的功能无。。。
接收到对int/float消息None的调用，带有（），{}
赛尔夫是5.6

---

如何不丢失

self

并将消息内容分派到

message

变量？

正如

def send\u message（self，message，*args，**kwargs）等Python方法签名所建议的那样，方法的第一个参数必须是
self
对象。通常，通过执行
obj.send_message
，您可以访问对象的方法，而不是类。请尝试以下操作：

>>> class Foo():
...     def bar(self):
...         pass

>>> Foo.bar
<function __main__.Foo.bar>

>>> Foo().bar
<bound method Foo.bar of <__main__.Foo object at 0x7f5fd927cc18>>

输出：

Dispatching to function <function Sender.send_message at 0x7f1e427e5488> with message 1 and extra payload None...
received call for int/float message 1 with (None,), {}
self is <__main__.Sender object at 0x7f1e4277b0f0>
Dispatching to function <function Sender.send_message at 0x7f1e427e5488> with message 2 and extra payload None...
received call for int/float message 2 with (None,), {}
self is <__main__.Sender object at 0x7f1e4277b0f0>
Dispatching to function <function Sender.send_message at 0x7f1e427e5598> with message True and extra payload None...
received call for bool message True with (None,), {}
self is <__main__.Sender object at 0x7f1e4277b0f0>
Dispatching to function <function Sender.send_message at 0x7f1e427e5488> with message 5.6 and extra payload None...
received call for int/float message 5.6 with (None,), {}
self is <__main__.Sender object at 0x7f1e4277b0f0>

调度到具有消息1和额外有效负载无的功能。。。
接收到对int/float消息1的调用，其中包含（无、）、{}
自我是
正在调度到具有消息2和额外有效负载无的功能。。。
接收到对int/float消息2的调用，其中包含（无、）、{}
自我是
正在调度到具有消息True和额外有效负载None的函数。。。
接收到对bool消息True的调用，带有（无，），{}
自我是
发送到带有消息5.6和额外有效负载的功能无。。。
接收到对int/float消息5.6的调用，其中包含（无、）、{}
自我是
除了我的答案之外，我建议您在这里查看：，特别是
核心
和
调度程序
，了解更完整实现的代码和/或灵感。
Dispatching to function <function Sender.send_message at 0x7f1e427e5488> with message 1 and extra payload None...
received call for int/float message 1 with (None,), {}
self is <__main__.Sender object at 0x7f1e4277b0f0>
Dispatching to function <function Sender.send_message at 0x7f1e427e5488> with message 2 and extra payload None...
received call for int/float message 2 with (None,), {}
self is <__main__.Sender object at 0x7f1e4277b0f0>
Dispatching to function <function Sender.send_message at 0x7f1e427e5598> with message True and extra payload None...
received call for bool message True with (None,), {}
self is <__main__.Sender object at 0x7f1e4277b0f0>
Dispatching to function <function Sender.send_message at 0x7f1e427e5488> with message 5.6 and extra payload None...
received call for int/float message 5.6 with (None,), {}
self is <__main__.Sender object at 0x7f1e4277b0f0>