How about defining path/4 like this? path(R_2, Xs, A,Z) :- % A path `Xs` from `A` to `Z` is … walk(R_2, Xs, A,Z), % … a walk `Xs` from `A` to `Z` … all_dif(Xs). % … with no duplicates in `Xs`. To aid universal termination, we swap the two goals in above conjunction … path(R_2, … Read more
What are the names of the algorithms and concepts used in Prolog? Logic programming Depth-first, backtracking search Unification See Sterling & Shapiro, The Art of Prolog (MIT Press) for the theory behind Prolog. Probably it builds some kind of tree structure or directed object graph, and then upon queries it traveres that graph with a … Read more
Single quoted items are always atoms. The meaning of double quotes depends on the Prolog flag double_quotes: atom — with this value “a” = a. Nowadays, this is rarely used. But you will find Prolog books where [“abc.pl”] is written. codes — a list of character codes. This is frequently the default, but it leads … Read more
avs_term_rearranged(AVs, T, AVsR) :- term_variables(T, Vs), copy_term(Vs+AVs, Vs1+AVs1), bind_names(AVs1), build_vn_list(Vs, Vs1, AVsR). bind_names([]). bind_names([N=V|AVs]) :- N = V, bind_names(AVs). build_vn_list([], [], []). build_vn_list([V|Vs],[N|Ns],NVs) :- ( atom(N) -> NVs = [N=V|NVs1] ; var(N) -> NVs = NVs1 ), build_vn_list(Vs, Ns, NVs1).
Adventure in Prolog Dennis Merritt | Springer Published in 1990, 186 pages An Introduction to Logic Programming through Prolog Michael Spivey | Prentice Hall Published in 2008, 258 pages Applications of Prolog Attila Csenki | BookBoon Published in 2009, 203 pages Artificial Intelligence through Prolog Neil C. Rowe | Prentice-Hall Published in 1988, 481 pages … Read more
Yes, there is such a control construct in ISO Prolog, called ->. You use it like this: ( condition -> then_clause ; else_clause ) Here is an example that uses a chain of else-if-clauses: ( X < 0 -> writeln(‘X is negative. That’s weird! Failing now.’), fail ; X =:= 0 -> writeln(‘X is zero.’) … Read more
First, allow me to compliment you on your fine pw0n1e icon. This is a tricky question to answer, largely because there are so many variants of both miniKanren and Prolog. miniKanren and Prolog are really families of languages, which makes it difficult to compare their features, or even how they are used in practice. Because … Read more