/**
* Initialize the choice point state.
*
* @param interpreter the parent interpreter whose state is to be preserved here, its arg stack
* defines the parameters for the target goal
*/
@Override
public void init(LPInterpreter interpreter) {
super.init(interpreter);
context = interpreter.getContext();
generator = interpreter.getEngine().generatorFor(goal);
generator.addConsumer(this);
resultIndex = 0;
}
/** Restore the state of an interpreter from this frame */
public void restoreState(LPInterpreter interp) {
interp.unwindTrail(0);
for (int i = 0; i < trailLength; i++) {
interp.bind(trailVars[i], trailValues[i]);
}
if (pVars != null) {
System.arraycopy(pVars, 0, envFrame.pVars, 0, pVars.length);
}
}
/** Return a safe copy of the list of matched subgoals in this subderivation. */
public List<Triple> getMatchList() {
ArrayList<Triple> matchList = new ArrayList<>();
for (TriplePattern matche : matches) {
matchList.add(LPInterpreter.deref(matche));
}
return matchList;
}
/** Return the final instantiated goal given the current binding state. */
public Triple getResult() {
return new Triple(
LPInterpreter.deref(argVars[0]),
LPInterpreter.deref(argVars[1]),
LPInterpreter.derefPossFunctor(argVars[2]));
}