1f19ac4da5
The unit test for this fails with GNU 4.6: Building CXX object CMakeFiles/test_cxx_variadic_templates.dir/cxx_variadic_templates.cpp.o CompileFeatures/cxx_variadic_templates.cpp: In static member function ‘static int Interface<I, Is>::accumulate()’: CompileFeatures/cxx_variadic_templates.cpp:18:31: sorry, unimplemented: cannot expand ‘Is ...’ into a fixed-length argument list CMakeFiles/test_cxx_variadic_templates.dir/build.make:54: recipe for target 'CMakeFiles/test_cxx_variadic_templates.dir/cxx_variadic_templates.cpp.o' failed The workaround is to use a specialization: http://stackoverflow.com/questions/1989552 http://stackoverflow.com/questions/11297376
66 lines
1.3 KiB
C++
66 lines
1.3 KiB
C++
template<int... Is>
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struct Interface;
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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()
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{
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return I;
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}
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};
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template<int I, int... Is>
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struct Interface<I, Is...>
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{
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static int accumulate()
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{
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return I + Interface<Is...>::accumulate();
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}
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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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enum {
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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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enum {
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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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template<typename T>
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struct B {
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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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template<typename T, typename U, typename...>
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struct D {
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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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