1 /*============================================================================= 2 Copyright (c) 2012 Joel falcou 3 4 Distributed under the Boost Software License, Version 1.0. (See accompanying 5 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6 ==============================================================================*/ 7 #include <iostream> 8 #include <boost/mpl/transform.hpp> 9 #include <boost/fusion/include/mpl.hpp> 10 #include <boost/fusion/adapted/mpl.hpp> 11 #include <boost/fusion/include/at.hpp> 12 #include <boost/fusion/include/as_vector.hpp> 13 #include <boost/type_traits/add_reference.hpp> 14 #include <boost/fusion/include/adapt_struct.hpp> 15 16 struct foo 17 { 18 double d; float f; short c; 19 }; 20 21 BOOST_FUSION_ADAPT_STRUCT(foo,(double,d)(float,f)(short,c)) 22 23 template<class T> 24 class composite_reference 25 : public boost::mpl:: 26 transform < typename boost::fusion::result_of:: 27 as_vector<T>::type 28 , boost::add_reference<boost::mpl::_> 29 >::type 30 { 31 public: 32 typedef typename boost::mpl:: 33 transform < typename boost::fusion::result_of:: 34 as_vector<T>::type 35 , boost::add_reference<boost::mpl::_> 36 >::type parent; 37 composite_reference(T & src)38 composite_reference(T& src) : parent( src ) {} composite_reference(parent & src)39 composite_reference(parent& src) : parent(src) {} 40 operator =(T & src)41 composite_reference& operator=(T& src) 42 { 43 static_cast<parent&>(*this) = static_cast<parent&>(src); 44 return *this; 45 } 46 operator =(parent const & src)47 composite_reference& operator=(parent const& src) 48 { 49 static_cast<parent&>(*this) = src; 50 return *this; 51 } 52 }; 53 main(int,char **)54int main(int,char**) 55 { 56 foo f; 57 composite_reference<foo> ref_f(f); 58 59 boost::fusion::at_c<0>(ref_f) = 1.2; 60 boost::fusion::at_c<1>(ref_f) = 1.2f; 61 boost::fusion::at_c<2>(ref_f) = 12; 62 63 std::cout << f.d << " " << f.f << " " << f.c << "\n"; 64 } 65