Overview

Metaclasses¶

• Understanding Python Classes
• Dynamic Class Creation
• More Accurate Dynamic Class Creation
• Metaclasses in Python
• Run Methods Order in Python
• Run Methods Order in Python with More Explanation
• Invisible Metaclasses in Python
• Meta Classes without type
• More Accurate Meta Classes without type

Examples¶

• Register Classes in Python
• Singleton in Python
• Auto Slots
• Logging Namespace
• Modeling a Class with a Metaclass
• Define Method If Condition True

Example on CPython

>>> import enum
>>> enum.Enum


>>> import abc
>>> abc.ABC


>>> import typing
>>> typing.Any

Example on 3.party libs

• https://github.com/django/django/blob/main/django/db/models/base.py#L92
• https://github.com/pydantic/pydantic/blob/main/pydantic/main.py#L47

Tutorial, Docs, Videos¶

• https://www.youtube.com/watch?v=yWzMiaqnpkI
• https://realpython.com/python-metaclasses/
• https://www.python.org/doc/essays/metaclasses/
• https://docs.python.org/3/reference/datamodel.html#customizing-class-creation
• https://peps.python.org/pep-3115/
• https://stackoverflow.com/questions/100003/what-are-metaclasses-in-python
• https://jfreeman.dev/blog/2020/12/07/python-metaclasses/
• https://blog.ionelmc.ro/2015/02/09/understanding-python-metaclasses/
• https://jfreeman.dev/blog/2020/12/07/python-metaclasses/
• https://peps.python.org/pep-3115/

CPython Implementation¶

• https://github.com/python/cpython/blob/main/Python/bltinmodule.c#L89