I have just uploaded Language::XSB to CPAN, a module to interface
Perl with the XSB system.
From the XSB manual:
XSB is a research-oriented Logic Programming and Deductive
Database System developed at SUNY Stony Brook. In
addition to providing all the functionality of Prolog, it
contains features not usually found in Logic Programming
Systems such as evaluation according to the Well Founded
Semantics through full SLG resolution, constraint handling
for tabled programs, a compiled HiLog implementation,
unification factoring and interfaces to other systems such
as ODBC, C, Java, Perl, and Oracle.