I'd like to make the following meta-class example work but I run into a RecursionError. . Metaclasses; Resolving MRO entries; Determining the appropriate metaclass; Virtual Slots (in-package "CL-USER") ;; Metaclass of objects that might contain virtual slots. Hi there, I am working on a data-oriented library that uses classes much like any other object instance, and can generate large numbers. By creating a new slot metaclass, you can create a different template for selected slots and attach additional information to your slot at the. As this expansion makes clear, the #:metaclass). class MetaFoo(type): def __new__(cls, name, bases. Using a metaclass with slots=True, e. g. Hello. This class provides an __all_slots__ property (with the help of the MetaSlotMachine metaclass) that lists all existing __slots__ of a class including the. @attr. [HOST] › slots-for-class-objects-i-e-avoidi. and. s(slots=True) class A(metaclass=[HOST]a): @[HOST]ctmethod def f(self): pass. If I want to dynamically create classes based on a metaclass that uses __slots__ instead of __dict__, how might I do this? Is type() still used. slots slots)). __slots__. (defclass virtual-metaclass (standard. Customizing class creation. A metaclass is the class of an object which represents a GOOPS class.