re2post(void)
{
    if (nfa_reg(REG_NOPAREN) == FAIL)
	return NULL;
    EMIT(NFA_MOPEN);
    return post_start;
}
re2post(void)
{
    if (nfa_reg(REG_NOPAREN) == FAIL)
	return NULL;
    EMIT(NFA_MOPEN);
    return post_start;
}