One of the most well-known commercial
implementations of the computer language Prolog
, and one of the few that is still maintained
. It is written by the SICS company in Sweden
It includes lots of nifty tools, e.g. for integrating Prolog in C and C in Prolog. Also, it includes a wide variety of extensions, so that you have a Prolog that can make TCP/IP connections and so on. It can compile Prolog programs so that they can run without the necessity of a Prolog interpreter.
It is expensive -- and is far more likely to be purchased by a university than by an individual, but SICS has an excellent reputation for support.
More information can be found at its Web page: http://www.sics.se/sicstus/