Get the full sources of the reference implementation of Kernel Prolog, a lightweight Java based Prolog interpreter with an innovative system of built-ins based on Fluents, a Prolog extension providing reflection and smooth interoperation with external objects. Or take a quick look at this White Paper. first!
How to participate in the Open Source development process:
Kernel Prolog is available in Open Source form under the GNU Public License (GPL) as described at: http://www.fsf.org/copyleft/gpl.html As a convenience to developers of non-GPL commercial applications, BinNet Corporation, who holds the copyright on the original Kernel Prolog code, will provide for a fee, an alternative commercial license, going beyond GPL, to developers preferring to build proprietary components embedding BinNet's version of Kernel Prolog in binary form. Contact BinNet Corporation at firstname.lastname@example.org for requests on arranging a customized commercial licensing model and for pricing of support services.
What's new in Kernel Prolog
Kernel Prolog replaces conventional side effects in Prolog by introducing first-class engines and FLUENTS - stateful objects which give a uniform view on external Java objects file streams, the Prolog database and resolution process. Still, the look and feel of basic Prolog and its (Horn Clause) syntax are preserved.
Kernel Prolog can be seen as an executable specification of how
a next generation Prolog can look - despite its compact design, it has features
going far beyond ISO Prolog.