It's hard to use Prolog without understanding its evaluation strategy, but what trips up beginners coming from other programming language is mostly getting the

It's hard to use Prolog without understanding its evaluation strategy, but what trips up beginners coming from other programming language is mostly getting the declarative reading correct. Ordering effects are not, in my experience, all that counter-intuitive, but Mercury removed multiple clauses to solve this problem. The actual language certainly does have a lot of complexity and mastery depends on understanding it, but this isn't really all that different from other systems, it just presents a very early stumbling block to seasoned programmers. You could still stuff fifteen Prolog's worth of complexity into C++.