src/main/java/com/basistech/tclre/Nfa.java
long analyze() {
        Arc a;
        Arc aa;

        if (pre.outs == null) {
            return Flags.REG_UIMPOSSIBLE;
        }
        for (a = pre.outs; a != null; a = a.outchain) {
            for (aa = a.to.outs; aa != null; aa = aa.outchain) {
                if (aa.to == post) {
                    return Flags.REG_UEMPTYMATCH;
                }
            }
        }
        return 0;
    }
long analyze() {
        Arc a;
        Arc aa;

        if (pre.outs == null) {
            return Flags.REG_UIMPOSSIBLE;
        }
        for (a = pre.outs; a != null; a = a.outchain) {
            for (aa = a.to.outs; aa != null; aa = aa.outchain) {
                if (aa.to == post) {
                    return Flags.REG_UEMPTYMATCH;
                }
            }
        }
        return 0;
    }
analyze - ascertain potentially-useful facts about an optimized NFA

@return re_info bits.