A Simple near-Horn Prolog Interpreter
Tristan B. Smith, W D Loveland · International Conference on Lightning Protection · 1988
We describe a simple interpreter for {\em near-Horn Prolog (nH-Prolog)}, an extension of Prolog that allows multiple-head clauses and negated facts. Our interpreter demonstrates that the operational semantics of nH-Prolog is as simple as originally promised - indeed, quite close to Prolog. We present the inner loop of our interpreter in the form of a Prolog meta-interpreter. The performance of this simple interpreter (within a factor of 4 of the underlying Prolog system on interpreting definite clause programs) is sufficient to experiment with nH-Prolog programming. The design of the interpreter suggests that inner loop speed close to Prolog''s is possible.