template <typename varT>
const std::string & x2str(varT x, std::string & s);
template <typename varT>
+const std::string & x2str(varT x) { std::string s; return x2str(x, s); }
+template <typename varT>
const std::string & unsigned2str(varT x, std::string & s);
+template <typename varT>
+const std::string & unsigned2str(varT x) { std::string s; return unsigned2str(x, s); }
//-----------------------------------------------------------------------------
template <typename varT>