/// This function is called when the buffer structure has been updated.
virtual void updateTocItem(std::string const &, DocIterator const &) = 0;
/// This function is called when some parsing error shows up.
/// This function is called when the buffer structure has been updated.
virtual void updateTocItem(std::string const &, DocIterator const &) = 0;
/// This function is called when some parsing error shows up.
/// This function is called when some message shows up.
virtual void message(docstring const &) = 0;
/// This function is called when the buffer busy status change.
/// This function is called when some message shows up.
virtual void message(docstring const &) = 0;
/// This function is called when the buffer busy status change.