Finally, at the predicate creation level of the program, the ordering of predicate specifications is important for Prolog. The issue is to utilize the built in depth-first left-to-right goal reduction...

Finally, at the predicate creation level of the program, the ordering of predicate specifications is important for Prolog. The issue is to utilize the built in depth-first left-to-right goal reduction of the Prolog interpreter. Understanding the action of the interpreter has important implications for using the order idiom. Along with order of specifications for efficient search, of course, is understanding and using wisely the predicate cut, !.