High-performance Prolog System

 High-performance Prolog compiler developed at LIACC/Universidade
 do Porto and at COPPE Sistemas/UFRJ. The YAP Prolog engine is based in the
 Warren Abstract Machine, with several optimizations for better
 performance. YAP follows the Edinburgh tradition, and is largely
 compatible with the ISO-Prolog standard and with Quintus and SICStus Prolog.
 .
 YAP features a constraint solver over real numbers, and support for
 constraint handling rules (CHR).