int setId(int id)
{
if (m_set_id) return id;
id = m_lhs->setId(id);
id = m_rhs->setId(id);
m_id = id;
m_set_id = true;
return m_id + 1;
}
int setId(int id)
{
if (m_set_id) return id;
id = m_child->setId(id);
m_id = id;
m_set_id = true;
return m_id + 1;
}