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  1. #include <iostream>
  2. #include <tuple>
  3. #include <type_traits>
  4.  
  5. #if 1 // Not in C++11 // make_index_sequence
  6. #include <cstdint>
  7.  
  8. template <std::size_t...> struct index_sequence {};
  9.  
  10. template <std::size_t N, std::size_t... Is>
  11. struct make_index_sequence : make_index_sequence<N - 1, N - 1, Is...> {};
  12.  
  13. template <std::size_t... Is>
  14. struct make_index_sequence<0u, Is...> : index_sequence<Is...> {};
  15.  
  16. #endif // make_index_sequence
  17.  
  18. template <typename TReturn, typename...TArgs>
  19. struct SomeFunction{
  20.     using ReturnType = TReturn;
  21.     using ArgTypes = std::tuple<TArgs...>;
  22.  
  23.     TReturn operator () (TArgs... args) const
  24.     {
  25.         const int dummy[] = {0, ((std::cout << args),0 )...};
  26.         static_cast<void>(dummy);
  27.     }
  28. };
  29.  
  30.  
  31.  
  32. template <typename TFunction, typename TupleArg = typename TFunction::ArgTypes>
  33. class Task;
  34.  
  35.  
  36. template <typename TFunction, typename... TArgs>
  37. class Task<TFunction, std::tuple<TArgs...>>
  38. {
  39. public:
  40.     Task(TFunction fun, TArgs...args) : fun_(fun), args_(args...) {}
  41.     void operator()()
  42.     {
  43.         call(make_index_sequence<sizeof...(TArgs)>{});
  44.     }
  45. private:
  46.     template <std::size_t ... Is>
  47.     void call(index_sequence<Is...>)
  48.     {
  49.         fun_(std::get<Is>(args_)...);
  50.     }
  51. private:
  52.     TFunction fun_;
  53.     std::tuple<TArgs...> args_;
  54. };
  55.  
  56. int main()
  57. {
  58.     SomeFunction<void, int, char> f;
  59.     Task<SomeFunction<void, int, char>> task(f, 42, 'c');
  60.  
  61.     task();
  62.  
  63.     return 0;
  64. }
  65.  
Success #stdin #stdout 0s 3296KB
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stdin
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Standard input is empty
stdout
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42c
https://ideone.com/ZzGUZ2
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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