Hello, I'm having trouble when adding elements to a ptr_map. If I use a ptr_vector instead, it works (code for ptr_map and ptr_vector follows). * With ptr_map: =============== #include <iostream> #include <string> #include <boost/function.hpp> #include <boost/any.hpp> #include <boost/ptr_container/ptr_map.hpp> class Base { }; class X : public Base { public: std::string text() { std::cout<< std::string("hello world!") << std::endl; return std::string("hello world!"); } }; class Y : public Base { public: int value() { return 5; } }; class Z : public Base { public: bool isEnabled() { return true; } }; // [...] // There will be hundreds of classes like X, Y and Z, only quite more complex class ProxyBase { public: virtual boost::any field() = 0; }; template<class T> class Proxy : public ProxyBase { typedef T result_type; public: Proxy(T& inst, boost::function<boost::any ( T )> f) : inst_(inst), f_(f) { ; }; boost::any field() { return boost::any( f_(inst_) ); } T& inst_; boost::function<boost::any ( T )> f_; }; int main() { boost::ptr_map<std::string, ProxyBase> m; X x; Proxy<X>* px = new Proxy<X>(x, boost::mem_fn(&X::text)); std::cout << "Calling a proxy object Proxy<X> outputs: " << boost::any_cast<std::string>( px->field() ) << std::endl; // m.insert(std::string("test"), px ); // FIXME Why does this 'insert' fail? // std::cout << "PTR_MAP Calling a proxy object Proxy<X> outputs: " << boost::any_cast<std::string>( m["test"].field() ) << std::endl; Y y; Proxy<Y>* py = new Proxy<Y>(y, boost::mem_fn(&Y::value)); std::cout << "Calling a proxy object Proxy<Y> outputs: " << boost::any_cast<int>( py->field() )<< std::endl; // m.insert(std::string("test2"), py); // FIXME Why does this 'insert' fail? // std::cout << "PTR_VECTOR Calling a proxy object Proxy<Y> outputs: " << boost::any_cast<int>( m["test2"].field() ) << std::endl; Z z; Proxy<Z>* pz = new Proxy<Z>(z, boost::mem_fn(&Z::isEnabled)); std::cout << "Calling a proxy object Proxy<Z> outputs: " << boost::any_cast<bool>( pz->field() )<< std::endl; // m.insert(std::string("test3"), pz); // FIXME Why does this 'insert' fail? // std::cout << "PTR_VECTOR Calling a proxy object Proxy<Z> outputs: " << boost::any_cast<bool>( m["test3"].field() ) << std::endl; return 0; } * With ptr_vector: ================== #include <iostream> #include <string> #include <boost/function.hpp> #include <boost/any.hpp> #include <boost/ptr_container/ptr_vector.hpp> class Base { }; class X : public Base { public: std::string text() { std::cout<< std::string("hello world!") << std::endl; return std::string("hello world!"); } }; class Y : public Base { public: int value() { return 5; } }; class Z : public Base { public: bool isEnabled() { return true; } }; // [...] // There will be hundreds of classes like X, Y and Z, only quite more complex class ProxyBase { public: virtual boost::any field( std::string name ) = 0; }; template<class T> class Proxy : public ProxyBase { typedef T result_type; public: Proxy(std::string name, T& inst, boost::function<boost::any ( T )> f) : name_(name), inst_(inst), f_(f) { ; }; boost::any field( std::string name ) { if( name == name_ ) { // Just a stub to simulate a container lookup return boost::any( f_(inst_) ); } } std::string name_; T& inst_; boost::function<boost::any ( T )> f_; }; int main() { boost::ptr_vector<ProxyBase> vec; X x; Proxy<X>* px = new Proxy<X>("test", x, boost::mem_fn(&X::text)); vec.push_back(px); std::cout << "Calling a proxy object Proxy<X> outputs: " << boost::any_cast<std::string>( px->field("test") ) << std::endl; std::cout << "PTR_VECTOR Calling a proxy object Proxy<X> outputs: " << boost::any_cast<std::string>( vec[0].field("test") ) << std::endl; Y y; Proxy<Y>* py = new Proxy<Y>("test2", y, boost::mem_fn(&Y::value)); vec.push_back(py); std::cout << "Calling a proxy object Proxy<Y> outputs: " << boost::any_cast<int>( py->field( "test2" ) )<< std::endl; std::cout << "PTR_VECTOR Calling a proxy object Proxy<Y> outputs: " << boost::any_cast<int>( vec[1].field("test2") ) << std::endl; Z z; Proxy<Z>* pz = new Proxy<Z>("test3", z, boost::mem_fn(&Z::isEnabled)); vec.push_back(pz); std::cout << "Calling a proxy object Proxy<Z> outputs: " << boost::any_cast<bool>( pz->field( "test3" ) )<< std::endl; std::cout << "PTR_VECTOR Calling a proxy object Proxy<Z> outputs: " << boost::any_cast<bool>( vec[2].field("test3") ) << std::endl; return 0; } -- Pau Garcia i Quiles http://www.elpauer.org (Due to my workload, I may need 10 days to answer)