The way I see it, a key attraction of Prolog and logic programming languages in general is that different evaluation strategies are possible, and in fact also s

The way I see it, a key attraction of Prolog and logic programming languages in general is that different evaluation strategies are possible, and in fact also starting to be implemented in several systems to various degrees. For example, an increasing number of Prolog systems provide, in addition to SLDNF resolution (which is the the default evaluation strategy), also SLG resolution (tabling) as an evaluation strategy with different termination and performance characteristics. These different strategies are very useful in practical programs, and it would be limiting if one were to prevent them by using extra-logical predicates.