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.
XGP is an integrated development environment that extends GNU Prolog to work with Cocoa under Macintosh OS X. It provides user interface and graphics facilities largely compatible with MacProlog32 by LPA. Requires Mac OS X version 10.2.1 or greater.
Mercury is a modern logic/functional programming language. The Mercury system includes a
compiler, debugger, libraries, sample code, profilers, etc. Mercury is designed to be the successor
of logic programming languages such as Prolog.
MatForce is a compiler that translates MatLab scripts into self-contained C++ code, producing human-readable, extensible C++ sources that can be fitted to the needs of the encapsulating application.