I'm new to Prolog. I'm just trying simple examples to learn. I have this .pl
file with these lines:
parent(pam,bob).
parent(tom,bob).
parent(tom,lio).
parent(bob,ann).
parent(bob,pat).
parent(pat,jim).
After consulting and testing, it only shows the first answer. For example:
5 ?- parent(X,Y).
X = pam,
Y = bob .
Isn't it supposed to give all the combinations that satisfy the relation parent
?
Do anyone have idea what the problem is?
don't hit enter after your first results shows, use spacebar instead
[Enter]
stops execution even if the backtracking is not completed yet[Spacebar]
or[;]
continues with backtracking from your last result to the next result orfalse
if there are no other results left.
来源:https://stackoverflow.com/questions/34463248/why-does-swi-prolog-only-give-me-the-first-answer