31   auto last = m_backrefs.size();
    32   m_backrefs.emplace_back(matcher);
    36 shared_ptr<RegexMatcher>
    39   auto backref = m_backrefs[i].lock();
    40   BOOST_ASSERT(backref != 
nullptr);
 
size_t pushRef(const shared_ptr< RegexMatcher > &matcher)
shared_ptr< RegexMatcher > getBackref(size_t i) const