## 1.2 Status

This manual describes version 5.6.59 of SWI-Prolog. SWI-Prolog has been used now for many years. The application range includes Prolog course material, meta-interpreters, simulation of parallel Prolog, learning systems, natural language processing, complex interactive systems, web-server and web-server components. Although in our experience rather obvious and critical bugs can remain unnoticed for a remarkable long period, we assume the basic Prolog system is fairly stable. Bugs can be expected in infrequently used built-in predicates.

Some bugs are known to the author. They are described as footnotes in this manual.