Python 带有_init_子类和子类注册表的注册表模式

我想创建一个设置注册表。我还希望能够在宏类别中分组设置

以下简化示例适用于单个注册表：

class RegistryHolder:
    registry = {}

    def __init_subclass__(cls, setting_name=None, **kwargs):
        super().__init_subclass__(**kwargs)
        cls.registry[setting_name] = cls

class SettingOne(RegistryHolder, setting_name='SettingOne'):
    pass

class SettingTwo(RegistryHolder, setting_name='SettingTwo'):
    pass

结果是：

print(RegistryHolder.registry)

{'SettingOne': <class '__main__.SettingOne'>,
 'SettingTwo': <class '__main__.SettingTwo'>}

这显然不起作用，因为当我将

RegistryHolder

子类化时，我正在将

User/System

类作为注册表的一部分进行“注册”，例如，对于

UserRegistryHolder.registry

我得到：

{'SettingOne': <class '__main__.SettingTwo'>, 
 'SettingTwo': <class '__main__.SettingTwo'>, 
 None: <class '__main__.UserRegistryHolder'>}

{'SettingOne'：，
“设置二”：，
无：}

所以有几个问题：

• 我问错问题了吗
• 我是不是想得太多了
• 您将如何干净地创建这样一个接口（欢迎使用替代方案）

---

假设

RegistryHolder

只是一个基类（模板），不应累加所有设置，而其子持有人

UserRegistryHolder/SystemRegistryHolder

应保留“各自的”设置：

class RegistryHolder:
    registry = {}

    def __init_subclass__(cls, setting_name=None, **kwargs):
        super().__init_subclass__(**kwargs)
        parent = cls.__bases__[0]
        if setting_name:
            parent.registry[setting_name] = cls  # add setting to parent sub-holder
        else:
            cls.registry = {}   # init registry for sub-holder


class UserRegistryHolder(RegistryHolder):
    pass

class SettingOne(UserRegistryHolder, setting_name='SettingOne'):
    pass

class SettingTwo(UserRegistryHolder, setting_name='SettingTwo'):
    pass

class SystemRegistryHolder(RegistryHolder):
    pass

class SettingA(SystemRegistryHolder, setting_name='SettingA'):
    pass

class SettingB(SystemRegistryHolder, setting_name='SettingB'):
    pass


print(RegistryHolder.registry)
print(UserRegistryHolder.registry)
print(SystemRegistryHolder.registry)

输出（连续）：

{}
{'SettingOne'：，'SettingTwo'：}
{'SettingA'：，'SettingB'：}

让我们详细说明一下：

RegistryHolder

只是一个基类，不应该累加所有设置，而它的子持有者

User/System

应该这样做，对吧？看起来你没有区分注册表和注册表持有者<代码>设置a是注册表，而不是注册表持有者。（或者，您可能希望区分注册表持有者和注册表持有者。）您希望宏类别中具有分组设置的此设置注册表看起来像什么？

{'SettingOne': <class '__main__.SettingTwo'>, 
 'SettingTwo': <class '__main__.SettingTwo'>, 
 None: <class '__main__.UserRegistryHolder'>}

class RegistryHolder:
    registry = {}

    def __init_subclass__(cls, setting_name=None, **kwargs):
        super().__init_subclass__(**kwargs)
        parent = cls.__bases__[0]
        if setting_name:
            parent.registry[setting_name] = cls  # add setting to parent sub-holder
        else:
            cls.registry = {}   # init registry for sub-holder


class UserRegistryHolder(RegistryHolder):
    pass

class SettingOne(UserRegistryHolder, setting_name='SettingOne'):
    pass

class SettingTwo(UserRegistryHolder, setting_name='SettingTwo'):
    pass

class SystemRegistryHolder(RegistryHolder):
    pass

class SettingA(SystemRegistryHolder, setting_name='SettingA'):
    pass

class SettingB(SystemRegistryHolder, setting_name='SettingB'):
    pass


print(RegistryHolder.registry)
print(UserRegistryHolder.registry)
print(SystemRegistryHolder.registry)

{}
{'SettingOne': <class '__main__.SettingOne'>, 'SettingTwo': <class '__main__.SettingTwo'>}
{'SettingA': <class '__main__.SettingA'>, 'SettingB': <class '__main__.SettingB'>}