Prolog: store solutions in a list

Question

This is a very simple question ;)

---

fact(a).

fact(b).

test(X):-fact(X).

---

the solutions are X=a; X=b. OK

I'm trying to create: test(X,L):-fact(X), ??? that returns L=[a,b]

can someone help me? Thanks.

Answer 1

Use findall/3 to aggregate solutions:

test(L):-
  findall(X, fact(X), L).