73 lines
1.4 KiB
C++
73 lines
1.4 KiB
C++
#if defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 407)
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#define OLD_GNU
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#endif
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#ifdef OLD_GNU
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template <int... Is>
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struct Interface;
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#endif
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template <int I, int... Is>
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struct Interface
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#ifdef OLD_GNU
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<I, Is...>
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#endif
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{
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static int accumulate() { return I + Interface<Is...>::accumulate(); }
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};
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template <int I>
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struct Interface<I>
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{
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static int accumulate() { return I; }
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};
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// Note: split this into a separate test if a
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// cxx_variadic_template_template_parameters feature is added.
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template <typename T>
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struct eval
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{
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enum
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{
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Matched = 0
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};
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};
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template <template <typename...> class T, typename... U>
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struct eval<T<U...> >
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{
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enum
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{
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Matched = 1
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};
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};
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template <typename...>
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struct A
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{
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};
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template <typename T>
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struct B
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{
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};
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template <typename T, typename U>
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struct C
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{
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};
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template <typename T, typename U, typename...>
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struct D
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{
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};
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// Note: This test assumes that a compiler supporting this feature
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// supports static_assert. Add a workaround if that does not hold.
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static_assert(eval<A<> >::Matched, "A Matches");
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static_assert(eval<A<int> >::Matched, "A Matches");
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static_assert(eval<A<int, char> >::Matched, "A Matches");
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static_assert(eval<B<int> >::Matched, "B Matches");
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static_assert(eval<C<int, char> >::Matched, "C Matches");
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static_assert(eval<D<int, char> >::Matched, "D Matches");
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static_assert(eval<D<int, char, bool> >::Matched, "D Matches");
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static_assert(eval<D<int, char, bool, double> >::Matched, "D Matches");
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