AMDG Joe Gottman wrote:
Mathias Gaunard wrote:
Arno Schödl wrote:
As a further extension, boost::get<S> where S is a base class of a T contained in the variant, should also work. I believe this would also be implementable with enable_if/disable_if, but we have not done it, so no guarantee.
Actually, it should work with all types that are convertible from any of the types of the variant.
Would it work for a type that is convertible from two or more of the types of the variant?
It had better not compile in that case, unless one of the types is a better match than the rest. How about implementing get along these lines (untested): template<class T, class Variant, class Base> struct get_impl : Base { operator typename mpl::at_c<typename Variant::types>::type&() const { return(get<T>(*this->variant)); } }; template<class Variant> struct get_impl_base { Variant* variant; }; template<class T, class Variant> T checked_get(const Variant& variant) { typename mpl::fold<typename Variant::types, get_impl_base<Variant>, get_impl<_1, Variant, _2> >::type impl; impl.variant = &variant; return T(impl); } In Christ, Steven Watanabe