Hi everyone. Last time I shared a post about Interface programming using abs in Python, and it got a lot of positive feedback—thank you!

Several people mentioned protocols, so I wrote a new article exploring that topic. In it, I compare protocols with abstract base classes and share my thoughts and experiences with both. You can check it out here: https://www.tk1s.com/python/protocols-vs-abstract-base-classes-in-python Hope you'll like it! Thanks!

Hello, if one finds interfaces useful in Python (>=3.8) and is convinced that static type-checking is a must, then why not ditch ABC and always use Protocols? I understand that the fundamental idea of a protocol is slightly different from an interface, but in practice, I had great success replacing abc's with Protocols without regrets.

With abc you would write (https://docs.python.org/3/library/abc.html) :

from abc import ABC, abstractmethod

class Animal(ABC):
   @abstractmethod
   def eat(self, food) -> float:
       pass

Whereas with Protocols it's gonna be (good tutorial):

from typing import Protocol

class Animal(Protocol):
   def eat(self, food) -> float:
       ...

Scores in my subjective scoring system :)

So I do not quite see why one should ever use ABC except for legacy reasons. Other (IMHO minor) points in favour of ABC I've seen were about interactions with code editors.

Did I miss anything?

I put more detailed arguments into a Medium. There are many tutorials on using Protocols, but not many on ABC vs Protocols comparisons. I found a battle of Protocols vs Zope, but we are not using Zope, so it's not so relevant.