has_subscript_operator.h

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

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}}}*/

#ifndef VC_TRAITS_HAS_SUBSCRIPT_OPERATOR_H_
#define VC_TRAITS_HAS_SUBSCRIPT_OPERATOR_H_

namespace has_subscript_operator_impl
{

template <typename T, typename I, typename = decltype(std::declval<T &>()[std::declval<I>()])> std::true_type test(int);
template <typename T, typename I> std::false_type test(float);

}  // namespace has_subscript_operator_impl

template <typename T, typename I = std::size_t>
struct has_subscript_operator : public decltype(has_subscript_operator_impl::test<T, I>(1))
{
};

static_assert(has_subscript_operator<int[]>::value, "");
static_assert(has_subscript_operator<int[], int>::value, "");
static_assert(!has_subscript_operator<int[], void *>::value, "");

#endif // VC_TRAITS_HAS_SUBSCRIPT_OPERATOR_H_