Prolog+CG is a Java implementation of Prolog with extensions implementing a subset of the Conceptual Graph (CG) theory of John Sowa. CGs are first-class datatypes on a par with terms. Object oriented extensions are also included.
Both forward-chaining and backward-chaining rules (which may include python code) are compiled into python. Can also automatically assemble python programs out of python functions which are attached to backward-chaining rules. See pyke.sourceforge.ne