Download of setup-gprolog-1.4.3-mingw-x86.exe (setup-gprolog-1.4.3-mingw-x86.exe ( external link: SF.net): 4,702,215 octetos) will begin shortly. If not so, click link on the left.
GNU Prolog is a free implementation (under GPL) of the logic programming language PROLOG. It can compile to native machine code which is extremely fast in execution. Another feature is the included constraint solver.