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Prolog in JavaScript.

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Prolog in Javascript

Here we collect the accumulated library functions of the previous versions.

This prolog is enhanced with the JavaScript callout capability though a rudimentary external/3 call; see the arithmetic functions for examples.

Licensing and so on

These days the kids are all about the licenses. I typically get a request or two every year from a keen undergrad who wants to turn this into something interesting. Consider this code to be under a two-clause (non-advertising) BSD-style license.

Having said that... I'm always interested to hear what people are up to with this, so if you feel keen or want a natter, drop me a line: logic@ioctl.org. I think that ideas are more important than kudos, but if you want to credit then I won't blush (and I'm sure my employer at the time I wrote this, the University of Bristol, wouldn't mind you mentioning them).

Good luck!

# Enter your ruleset in here. triple(sc, a, b). triple(sc, b, c). triple(sc, c, d). triple(sc, d, e). triple(sc, e, f). triple(sc, f, g). triple(type, sc, transitive). triple(P, X, Y) :- NOTTHIS triple(type, P, transitive), NOTTHIS triple(P, X, Z), triple(P, Z, Y). arcsOut(X, L) :- bagof(O, triple(P, X, O), L). ### Accumulated standard library lives under here! # unification and ( x, y, z; w ) support unify(X, X). # ( a, b, c ) --> conjunction([a, b, c]) conjunction([]). conjunction([X | Rest]) :- call(X), conjunction(Rest). # ( a; b; c ) --> disjunction([a, b, c]) disjunction([X | Rest]) :- call(X). disjunction([X | Rest]) :- disjunction(Rest). # Arithmetic add(A, B, C) :- external("$1 + $2", [A, B], C). # A + B = C, etc. sub(A, B, C) :- external("$1 - $2", [A, B], C). mul(A, B, C) :- external("$1 * $2", [A, B], C). div(A, B, C) :- external("$1 / $2", [A, B], C). # The canonical quicksort qsort([], []). qsort([X|Rest], Answer) :- partition(X, Rest, [], Before, [], After), qsort(Before, Bsort), qsort(After, Asort), append(Bsort, [X | Asort], Answer). partition(X, [], Before, Before, After, After). partition(X, [Y | Rest], B, [Y | Brest], A, Arest) :- leq(X, Y), partition(X, Rest, B, Brest, A, Arest). partition(X, [Y | Rest], B, Brest, A, [Y | Arest]) :- gtr(X, Y), partition(X, Rest, B, Brest, A, Arest). leq(X, Y) :- compare(X, Y, gt). leq(X, Y) :- compare(X, Y, eq). gtr(X, Y) :- compare(X, Y, lt). # Some list-processing stuff... append([], Z, Z). append([A|B], Z, [A|ZZ]) :- append(B, Z, ZZ). reverse([], []). reverse([A|B], Z) :- reverse(B, Brev), append(Brev, [A], Z). length([], 0). length([H|T], N) :- length(T, M), add(M, 1, N). # Standard prolog not/1 not(Term) :- call(Term), !, fail. not(Term). # Standard prolog var/1 var(X) :- bagof(l, varTest(X), [l, l]). varTest(a). tarTest(b).