On Sun, May 10, 2015 at 12:11 PM, Rob Stewart <rob.stewart@verizon.net> wrote:
Create customization points. Implement the default access method and permit customization for other types. You could provide some common specializations in separate headers so users don't always have to reinvent the same wheel.
So I worked on this a little bit. What I did was make a function pointer to allow the user to define their own access function. They could write something along the lines of template<typename T> void* get_boost_any(boost::any* data) { return (void*)boost::any_cast<T>(data); } template<typename U, typename T1, typename T2, ... typename TN> void* get_boost_variant(boost::variant<T1,T2,...,TN>* data) { return (void*)boost::get<U>(data); } The problem with this is there is a separate function for each T created so a single function pointer doesn't quite work. To get around that, I am thinking of having an array of function pointers, and the user will have to set the function pointer for each type explicitly. typedef data_type boost::any; // typedef data_type boost::variant<int, double, std::string> typedef container_type std::vector<data_type>; // typedef container_type std::list<data_type> container_type my_container; // fill my_container with data poly_adaptor<container_type, data_type> p(my_container); p.set_get_function(get_boost_any<int>); p.set_get_function(get_boost_any<double>); p.set_get_function(get_boost_any<std::string>); // p.set_get_function(get_boost_variant<int, int, double, std::string>); // p.set_get_function(get_boost_variant<double, int, double, std::string>); // p.set_get_function(get_boost_variant<std::string, int, double, std::string>); // now we can access data in p for int, double, and std::string //iterate over all ints for( auto itr = p.begin<int>(); itr != p.end<int>; ++p) { std::cout << *itr << std::endl } Interested in hearing ideas on a better implementation besides this. This is my first time really coding anything along these lines, so its really fun/interesting thinking through these issues. But, I am sure that lack of experience means I am overlooking some more elegant methods ;)