Re: SFINAE and non member functions detection.
Am 09.12.2010 19:51, schrieb Daniel Kr?gler:
On 2010-12-09 01:15, Daniel Kr?gler wrote:
The following is somewhat less intrusive: All internals have been moved
into "non-public" namespaces. I also replaced your deduction mechanism
by a different approach. Assuming the three used C++0x components are
replaced by corresponding C++03 versions, this should work well with
e.g. the Comeau compiler.
We can do a bit better by ensuring that the fallback function is even worse than a function whose parameter-declaration-clause terminates with an ellipsis:
#include <type_traits>
#include <utility>
namespace details {
struct never{};
Add here:
struct everything { everything(...); };
}
#define DEFINE_HAS_FREE_FUNCTION_TRAIT(name) \
namespace details_##name {\
details::never name(...);\
.... and replace above declaration by:
details::never name(details::everything);\
}\
namespace details {\
using namespace details_##name;\
\
template<class T>\
struct has_free_function_##name##_impl {\
typedef std::integral_constant<bool,\
!std::is_same<decltype(name(std::declval<T>())),\
details::never>::value> result;\
};\
}\
template<class T>\
struct has_free_function_##name :\
details::has_free_function_##name##_impl<T>::result {}
HTH & Greetings from Bremen,
Daniel Kr?gler
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