public Pack fromDefault(Pack pack) {
Rule rule = pack.getRule();
Target target = rule.getTarget();
TuplePrototype targetPrototype = target.getPrototype();
Function call = pack.getPriorCall();
if (call == null) {
throw new DefaultPackExpansionException("Cannot use implicit pack in a call-free chain.");
}
TuplePrototype callPrototype = target.getPrototype();
if (callPrototype.size() != targetPrototype.size()) {
throw new DefaultPackExpansionException(
"Default pack cannot be created because tuple prototypes are of different lengths.");
}
Pack newPack = (Pack) adaptor.dupNode(pack);
for (int i = 0; i < targetPrototype.size(); i++) {
TupleRef ref = (TupleRef) adaptor.create(TUPLE_REF, "");
adaptor.addChild(ref, adaptor.create(NUMBER, Integer.toString(i)));
adaptor.addChild(newPack, ref);
}
return newPack;
}
