Mercury is a promising logic programming language that's under development https://github.com/Mercury-Language/mercury
Tutorial available here (the "Ralph Becket Murcury tutorial" pdf) http://mercurylang.org/documentation/documentation.html
Tutorial available here (the "Ralph Becket Murcury tutorial" pdf) http://mercurylang.org/documentation/documentation.html
And just to tie this back to the original topic, Leon Sterling (first author of The Art of Prolog) was the head of the Department of Computer Science at the University of Melbourne when the development of Mercury began there.