SICStus

SICStus Prolog is a commercial Prolog implementation developed by the Swedish Institute of Computer Science (SICS). It provides a high-performance Prolog runtime that aims for compatibility with the ISO Prolog standard while offering a set of extensions for applications in industry and research.

The system includes a multi-threaded engine, a module system for encapsulation and reuse, and a foreign language interface that allows embedding Prolog in C and calling C libraries from Prolog. It also offers libraries for constraint programming, including CLP(FD), CLP(Q), and CLP(R), enabling constraint-based problem solving within Prolog programs. The runtime emphasizes fast term indexing, backtracking, and garbage collection to support large-scale applications.

SICStus Prolog is available on major platforms, including Windows and Unix-like systems, with 32- and 64-bit builds. It provides development tools such as an interactive top-level, a debugger, and a profiler to aid software development and performance tuning.

Licensing is commercial, with academic and evaluation licenses typically available for non-commercial use. The product is used in both industry and academia, in domains such as artificial intelligence, scheduling, and knowledge representation.

A short history: SICStus Prolog originated in the 1990s from SICS and has since become a widely used Prolog system in research and industry, known for its reliability and performance.