Efficient support for reactive rules in prolog

FW-rules is a Prolog library which provides efficient support for forward (reactive) rules in Prolog. The library is based on an indexing mechanism to achieve efficiency, it supports interoperability between the forward chaining language and the underlying Prolog engine, and it can be embedded in any Prolog application. The implementation is based on a runtime support written in C to perform indexing efficiently, and it relies on Prolog for the evaluation of rules. In this paper we describe the library, the compiler and the indexing mechanism. Finally, we compare FW_rules with other approaches to the implementation of production rules in Prolog and with other public-domain production systems, presenting a set of benchmarks.