Dear Eduardo,
Do you need to manage a specific expert system ? Could you be more specific about your needs ?
I would say that Prolog could be considered as an expert system too, and using hashes we can simulate Prolog's logic. We published several examples here using hashes that mimics prolog's way of working. Very interesting
But to me, OpenAI GPT3 is far more powerful than those old systems. With OpenAI GPT3 you can have really impressive conversations, explanations, briefs, etc