+IMPLEMENT_ARITHMETIC_OPERATOR (Moment, +);
+IMPLEMENT_ARITHMETIC_OPERATOR (Moment, -);
+IMPLEMENT_ARITHMETIC_OPERATOR (Moment, /);
+IMPLEMENT_ARITHMETIC_OPERATOR (Moment, *);
+IMPLEMENT_ARITHMETIC_OPERATOR (Moment, %);
+
+DECLARE_UNSMOB (Moment, moment);
+int compare (Moment const &, Moment const &);
+INSTANTIATE_COMPARE (Moment const &, Moment::compare);