B-Prolog is a high-performance implementation of the standard Prolog language with several extended features including matching clauses, action rules for event handling, finite-domain constraint solving, arrays and hash tables, declarative loops, and tabling. First released in 1994, B-Prolog is now a widely used CLP system. The constraint solver of B-Prolog was ranked top in two categories in the Second International Solvers Competition, and it also took the second place in P class in the second ASP solver competition and the second place overall in the third ASP solver competition. B-Prolog underpins the PRISM system, a logic-based probabilistic reasoning and learning system. B-Prolog is a commercial product, but it can be used for learning and non-profit research purposes free of charge (since version 7.8 for individual users, including commercial individual users, B-Prolog is free of charge ).
Read more about B-Prolog: Matching Clauses, Action Rules, CLP(FD), Arrays and The Array Subscript Notation, Loops With Foreach and List Comprehension, Tabling