As I mentioned in another comment, SLG resolution (implemented in XSB Prolog and more recently in SWI-Prolog) does alter the execution model in a way that makes

As I mentioned in another comment, SLG resolution (implemented in XSB Prolog and more recently in SWI-Prolog) does alter the execution model in a way that makes it easier to avoid extralogical constructs. And the wide availability of deeply integrated CLP modules for eg SWI-Prolog also makes it easier to keep programs purely logical.