Swi-prolog is a fast and powerful iso/edinburgh-style prolog compiler with a rich set of built-in predicates. it offers a fast, robust and small environment which enables substantial applications to be developed with it.

swi-prolog additionally offers:

* a powerful module system
* garbage collection
* unicode character set handling
* unbounted integer and rational number arithmetic
* multithreading support
* a powerful c/c++ interface
* gnu readline interface
this package provides libraries to parse sgml, xml and html data into prolog data structures. the high-level interface defined in sgml provides access at the file level, while the low-level interface defined in a foreign module works with prolog streams.