is_functor_argument_immutable.h

/*  This file is part of the Vc library. {{{
Copyright © 2014-2015 Matthias Kretz <kretz@kde.org>
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#ifndef VC_TRAITS_IS_FUNCTOR_ARGUMENT_IMMUTABLE_H_
#define VC_TRAITS_IS_FUNCTOR_ARGUMENT_IMMUTABLE_H_

namespace Vc_VERSIONED_NAMESPACE
{
namespace Traits
{
namespace is_functor_argument_immutable_impl
{
// this indirection for decltype is required for EDG based compilers
template <typename F, typename A> struct workaround_edg
{
    typedef decltype(&F::template operator()<A>) type;
};

template <typename F, typename A,
          typename MemberPtr = typename workaround_edg<F, A>::type,
          typename = decltype((std::declval<F &>().*
                               (std::declval<MemberPtr>()))(std::declval<const A &>()))>
std::true_type test(int);
template <typename F, typename A> std::false_type test(...);
}  // namespace is_functor_argument_immutable_impl

template <typename F, typename A>
using is_functor_argument_immutable =
    decltype(is_functor_argument_immutable_impl::test<F, A>(1));

}  // namespace Traits
}  // namespace Vc

#endif  // VC_TRAITS_IS_FUNCTOR_ARGUMENT_IMMUTABLE_H_

// vim: foldmethod=marker