[Boost-users] [FunctionTypes] Getting functor/lambda parameters (VS2012)

Subject: [Boost-users] [FunctionTypes] Getting functor/lambda parameters (VS2012)
From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2013-06-23 16:44:21

Hi,

I'm using C++ compiler from the latest VS2012.

I'm trying this simple technique to determined type of
functor or lambda call parameter, it works well:

#include <boost/function_types/parameter_types.hpp>
int main()
{
    auto foo = [](int) -> void {};
    typedef decltype(foo) foo_type;

    typedef boost::function_types::parameter_types
        <
        decltype(&foo_type::operator())
        >::type parameter_types;
}

Next, I move the typedef into class template, in constructor body,
it works well too:

template <typename T>
struct A
{

    A(T t)
    {
        typedef typename boost::function_types::parameter_types
            <
            decltype(&T::operator())
            >::type parameter_types;
    }
};

Finally, I move further with the technique, so I can access parameter types
within class template scope:

template <typename T>
struct B
{
    typedef typename boost::function_types::parameter_types
        <
        decltype(&T::operator())
        >::type parameter_types;
};

This example does compile with clang 3.4 (svn trunk) and GCC 4.8.1,
but it does not compile with Visual C++ 11.0.

Does anyone understand what C++11 feaure VS2012 is lacking
so it prevents compilation of the sample with B template above?

Here is complete .cpp file https://gist.github.com/mloskot/5846468

Best regards,
--
Mateusz  Loskot, http://mateusz.loskot.net