Christoph Heindl wrote:
Hi all,
I couldn't find any boost::get<T> style accessors for boost::any, so I came up with an implementation that looks something along the following lines.
#include <boost/any.hpp> #include <boost/call_traits.hpp>
namespace boost {
template<class T> typename boost::call_traits<T>::reference get(any &a) { return boost::any_cast<typename boost::call_traits<T>::reference>(a); }
template<class T> typename boost::call_traits<T>::const_reference get(const any &a) { return boost::any_cast<typename boost::call_traits<T>::const_reference>(a); } }
In case it cannot be converted to the desired destination type a bad_any_cast exception is thrown.
The above code enables boost.any and boost.variant to be used interchangeably as far as boost::get<T> is concerned.
Any thoughts?
Best regards, Christoph _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
You may want to extend this by adding support for get(any*) and get(any const*). Also, for making them usable interchangeably via boost::get, you need them to throw the same exception. Therefore, in case you are using boost::any, you probably want to rethrow bad_any_cast to bad_get. namespace boost { template<class T> typename boost::call_traits<T>::reference get(any &a) { try { return boost::any_cast<typename boost::call_traits<T>::reference>(a); } catch (boost::bad_any_cast const &) { throw(boost::bad_get()); } } template<class T> typename boost::call_traits<T>::const_reference get(const any &a) { try { return boost::any_cast<typename boost::call_traits<T>::const_reference>(a); } catch (boost::bad_any_cast const &) { throw(boost::bad_get()); } } template <class T> T* get (any *a) { return boost::any_cast<T>(a); } template <class T> T const* get (const any *a) { return boost::any_cast<T>(a); } } Yours, Stefan P.S. While looking through [1] I noticed that boost::bad_get is missing a nothrow virtual dtor: virtual ~bad_get() throw() { } Unless I'm wrong, someone should probably add that there.