public static class StateFactory {
protected State refLabel(State parent,StartTagInfo tag) { return new ElementRefState(); }
protected State hedgeRef(State parent,StartTagInfo tag) { return new HedgeRefState(); }
protected State choice(State parent,StartTagInfo tag) { return new ChoiceState(); }
protected State none(State parent,StartTagInfo tag) { return new TerminalState(Expression.nullSet); }
protected State empty(State parent,StartTagInfo tag) { return new TerminalState(Expression.epsilon); }