// add to the list of characters to read before actually reading
// the stream
- void putback(docstring s);
+ void putback(const docstring &s);
/// Like std::istream::get()
iparserdocstream & get(char_type &c);
///
std::string verbatimOption();
///
- void error(std::string const & msg);
+ void error(std::string const & msg) const;
/// The previous token.
Token const prev_token() const;
/// The current token.