Mac users interested in Xgp from lindsey spratt generally download:
XGP is an integrated development environment the extends gprolog to work with Cocoa under Macintosh OS X (10.6). It extends gprolog with builtins predicates for dialog, menu, and graphics facilities.
gprolog (GNU Prolog) is primarily the work of Daniel Diaz, It is a largely ISO standard-compliant Prolog, extended with constraint logic programming. It runs on many platforms.
