Options
\dlpindex{options}
It is possible to declare how many solutions may be produced
by setting the option sol as in
.ds nat7.pl
that will, when evaluating number, only produce the first seven
natural numbers, including zero.
It is important to note
that backtracking occurs on the resumption goal
and not over the statement creating the process for evaluating a goal.
For example the declaration
.ds a.pl
will effect that the goal
:- Q = a!g(X), (X=3; X=2), Q?.
fails, whereas the goal
:- Q = a!g(X), Q?, (X=3; X=2).
succeeds, since the binding in the first goal cannot be reached
due to the fact that a produces only the solutions and .