Its descendant, "Visual Prolog"[0], appears to have a free edition for personal use[1]. [0] https://en.wikipedia.org/wiki/Visual_Prolog https://en.wikipedia.or

Its descendant, "Visual Prolog"[0], appears to have a free edition for personal use[1]. [0] https://en.wikipedia.org/wiki/Visual_Prolog https://en.wikipedia.org/wiki/Visual_Prolog "Visual Prolog, also formerly known as PDC Prolog and Turbo Prolog, is a strongly typed object-oriented extension of Prolog. As Turbo Prolog it was marketed by Borland, but it is now developed and marketed by the Danish firm Prolog Development Center (PDC) that originally developed it. " [1] http://www.visual-prolog.com/vip/download/default.htm http://www.visual-prolog.com/vip/download/default.htm