Consider Soufflé, designed for large scale program analysis. Or LogiQL, designed for efficient incremental evaluation.
You also failed to disclose that you are not exactly unbiased individual here.
I have now looked up these systems: They are far removed from standard Prolog syntax, much farther than the system outlined in the posted article, which uses almost Prolog syntax to such an extreme extent that one of the given examples is already valid Prolog syntax and even a valid Prolog program without any changes. Therefore, the question I posted above ("If you are that close to using Prolog syntax, ...") does not apply to the same extent to these systems.
> You also failed to disclose that you are not exactly unbiased individual here.
Personally, I believe I have a solid grasp on the benefits of using standard Prolog syntax and the disadvantages of so slightly deviating from it, and I also believe that the question I asked is justified and what I stated in this thread is true.
If you see a need for any disclosure beyond what I stated above, please add it and what you believe to be the nature of my bias as your reply to this post for everyone to see. Thank you a lot!