Hi, I update Multimethod. I make Multimethod::ApplyTraits to control method's dispatching. https://svn.boost.org/trac/boost/attachment/ticket/2749/Multimethod.4.hpp Samples: ______________________________________________________________________ struct Method10 { // MultiMethod string operator()(const int a) const { return string("int: "+lexical_cast<string>(a)); }; string operator()(const double a) const { return string("double: "+lexical_cast<string>(a)); }; }; struct Method11 : public Method10 {}; struct Apply10 { // ApplyTraits to change int <-> double template<typename A00> string operator()(A00& a00, const double a01) { return a00(static_cast<int>(a01)); }; template<typename A00> string operator()(A00& a00, const int a01) { return a00(static_cast<double>(a01)); }; }; // you can set ApplyTraits to each type combination. // custom ApplyTraits bool m10(Multimethod::entry<string, any, Method10, const int>(Apply10())); bool m11(Multimethod::entry<string, any, Method10, const double>(Apply10())); // use default ApplyTraits bool m12(Multimethod::entry<string, any, Method11, const int>()); bool m13(Multimethod::entry<string, any, Method11, const double>()); BOOST_AUTO_TEST_CASE(test01) { Method10 m10; any mm(m10); BOOST_CHECK_EQUAL(Multimethod::apply<string>(mm, 1), "double: 1"); BOOST_CHECK_EQUAL(Multimethod::apply<string>(mm, 1.0), "int: 1"); Method11 m11; mm = m11; BOOST_CHECK_EQUAL(Multimethod::apply<string>(mm, 1), "int: 1"); BOOST_CHECK_EQUAL(Multimethod::apply<string>(mm, 1.0), "double: 1"); } // you can also use ApplyTraits to fit functions to multi methods. struct Method00 { // MultiMethod string operator()() const { return string("string()"); }; }; struct Apply00 { // ApplyTraits template<typename A00> shared_ptr<any> operator()(A00& a00) { return shared_ptr<any>(new any(a00())); }; }; // entry Method00::operator()() with ApplyTraits bool m00(Multimethod::entry<shared_ptr<any>, any, Method00>(Apply00())); BOOST_AUTO_TEST_CASE(test00) { Method00 m; any mm(m); shared_ptr<any> r(Multimethod::apply<shared_ptr<any> >(mm)); BOOST_CHECK_EQUAL(any_cast<string>(*r), "string()"); } _____________________________________________________________________ Regrads. Nowake