edu_video_gen

""" meta.py Some useful metaclasses. """ from __future__ import annotations from typing import TYPE_CHECKING if TYPE_CHECKING: from typing import Any class LeafClassesMeta(type): """ A metaclass for classes that keeps track of all of them that aren't base classes. >>> Parent = LeafClassesMeta('MyParentClass', (), {}) >>> Parent in Parent._leaf_classes True >>> Child = LeafClassesMeta('MyChildClass', (Parent,), {}) >>> Child in Parent._leaf_classes True >>> Parent in Parent._leaf_classes False >>> Other = LeafClassesMeta('OtherClass', (), {}) >>> Parent in Other._leaf_classes False >>> len(Other._leaf_classes) 1 """ _leaf_classes: set[type[Any]] def __init__( cls, name: str, bases: tuple[type[object], ...], attrs: dict[str, object], ) -> None: if not hasattr(cls, '_leaf_classes'): cls._leaf_classes = set() leaf_classes = getattr(cls, '_leaf_classes') leaf_classes.add(cls) # remove any base classes leaf_classes -= set(bases) class TagRegistered(type): """ As classes of this metaclass are created, they keep a registry in the base class of all classes by a class attribute, indicated by attr_name. >>> FooObject = TagRegistered('FooObject', (), dict(tag='foo')) >>> FooObject._registry['foo'] is FooObject True >>> BarObject = TagRegistered('Barobject', (FooObject,), dict(tag='bar')) >>> FooObject._registry is BarObject._registry True >>> len(FooObject._registry) 2 '...' below should be 'jaraco.classes' but for pytest-dev/pytest#3396 >>> FooObject._registry['bar'] <class '....meta.Barobject'> """ attr_name = 'tag' def __init__( cls, name: str, bases: tuple[type[object], ...], namespace: dict[str, object], ) -> None: super(TagRegistered, cls).__init__(name, bases, namespace) if not hasattr(cls, '_registry'): cls._registry = {} meta = cls.__class__ attr = getattr(cls, meta.attr_name, None) if attr: cls._registry[attr] = cls