I'm beginner in SWI-Prolog (but have some experience in Borland Prolog), and I've faced with a strange behavior for the following test code:
test(10).
test(1).
It is expected for query ?-test(A) to get 2 solutions, something like A = 10; A = 1. However, only A = 10 is produced. I don't use the cut here. Maybe backtracking is off by default in SWI-Prolog?
Thanks in advance
bagof/3 is probably what you're looking for.
?- bagof(X, test(X), Xs).
where Xs is a list of all matching results.
Know that anonymous variables don't work how you might expect with bagof. In the following example:
test(1,odd).
test(2,even).
test(3,odd).
test(4,even).
bagof(X, test(X,_), Xs) will only give values of X where the second term is uniform; in this case only the even numbers. If you want to return all matching value you need to do something like
?- bagof(X, A^test(X,A), Xs).