+ // What we would really like to do here is simply use a
+ // deque<StartTag>. But we want to store both StartTags and
+ // sub-classes thereof on this stack, which means we run into the
+ // so-called polymorphic class problem with the STL. We therefore have
+ // to use a deque<StartTag *>, which leads to the question who will
+ // own these pointers and how they will be deleted, so we use shared
+ // pointers.
+ ///
+ typedef shared_ptr<html::StartTag> TagPtr;
+ typedef std::deque<TagPtr> TagDeque;
+ ///
+ template <typename T>
+ shared_ptr<T> makeTagPtr(T const & tag)
+ { return shared_ptr<T>(new T(tag)); }
+ ///
+ TagDeque pending_tags_;
+ ///
+ TagDeque tag_stack_;