AI::Prolog is a predicate logic engine implemented in pure Perl. In predicate logic, instead of telling the computer how to do something, you tell the computer what something is and let it figure out how to do it. Conceptually, this is similar to regular expressions. The AI::Prolog distribution contains a Prolog shell called aiprolog and two short adventure games, spider.pro and sleepy.pro.
Pixy is a declarative graph query language that works on any Blueprints-compatible graph database. The Blueprints API provides a common interface to over a dozen graph databases, including Neo4J, Titan, Infinite Graph, OrientDB, DEX, and Bitsy. Pixy enables complex pattern matching and logic programming on graph databases by translating PROLOG-style rules and goals to Gremlin pipelines that represent graph traversal operations. Queries in Pixy can also be seemlessly integrated into Gremlin expressions. The combination of Pixy and Gremlin gives the programmer the full power of two graph querying paradigms, viz. graph pattern matching and graph traversal.