In Python 3.6, PEP 487 added the __init_subclass__
special method, which simplifies and extends class customization without using metaclasses. Consequently, this feature allows for creating simple plugins. Here we demonstrate this feature by modifying a prior example:
class Base:
plugins = []
def __init_subclass__(cls, **kwargs):
super().__init_subclass__(**kwargs)
cls.plugins.append(cls)
def test(self):
print("Base.")
class PluginA(Base):
def test(self):
super().test()
print("Plugin A.")
class PluginB(Base):
def test(self):
super().test()
print("Plugin B.")
Results:
PluginA().test()
# Base.
# Plugin A.
PluginB().test()
# Base.
# Plugin B.
Base.plugins
# [__main__.PluginA, __main__.PluginB]