On Sun, May 10, 2015 at 12:11 PM, Rob Stewart
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
void* get_boost_variant(boost::variant* 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
typedef container_type std::vector;
// typedef container_type std::list
container_type my_container;
// fill my_container with data
poly_adaptor 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_anystd::string);
// p.set_get_function(get_boost_variant);
// p.set_get_function(get_boost_variant);
// p.set_get_function(get_boost_variant);
// 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 ;)
