> However, often it happens that the system does it in a way that's somehow horribly inefficient and makes it totally unusable. And then I have to redeclare my

> However, often it happens that the system does it in a way that's somehow horribly inefficient and makes it totally unusable. And then I have to redeclare my requirements in a slightly different way to nudge the system into doing it differently - and this is much harder, then I have to worry about much more moving parts than just my code. Why would you expect this not to happen for complex programs? Declarative languages are never going to have a compiler so smart you can completely forget about optimising. They let you get certain tasks done easily when performance isn't essential and when optimal performance is essential you need to know what's going on underneath. Prolog execution is essentially navigating a massive search tree. There's always going to be plenty of ways to prune the tree and optimise traversal.