@Override
public V<T> reduce(@Nonnull FeatureExpr reducedConfigSpace) {
assert reducedConfigSpace != null;
FeatureExpr newCondition = configSpace.and(reducedConfigSpace);
if (newCondition.isSatisfiable()) return new One(newCondition, value);
else return VEmpty.instance();
}
@Override
public V<T> select(FeatureExpr selectConfigSpace) {
assert selectConfigSpace.implies(configSpace).isTautology()
: "selecting under broader condition ("
+ selectConfigSpace
+ ") than the configuration space described by One ("
+ configSpace
+ ")";
FeatureExpr newCondition = configSpace.and(selectConfigSpace);
if (newCondition.isSatisfiable()) return new One(newCondition, value);
else return VEmpty.instance();
}