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  1. #include <utility>
  2. #include <iostream>
  3. #include <tuple>    
  4.  
  5.  
  6. template<int...> struct seq {};
  7. template<int Min, int Max, int... s> struct make_seq:make_seq<Min, Max-1, Max-1, s...> {};
  8. template<int Min, int... s> struct make_seq<Min, Min, s...> {
  9.   typedef seq<s...> type;
  10. };
  11. template<int Max, int Min=1>
  12. using MakeSeq = typename make_seq<Min, Max>::type;
  13.  
  14. template<typename Func, typename Tuple, int... s>
  15. void do_call( Func&& f, seq<s...>, Tuple&& tup ) {
  16.   std::forward<Func>(f)( std::get<s>(std::forward<Tuple>(tup))... );
  17. }
  18.  
  19. typedef void(*pvoidary)(void*);
  20.  
  21. template<typename Lambda>
  22. struct pvoidary_factory {
  23.   Lambda func;
  24.   pvoidary_factory( Lambda const& f ):func(f) {}
  25.   pvoidary_factory( pvoidary_factory const& ) = default;
  26.   pvoidary_factory( pvoidary_factory && ) = default;
  27.   template<typename... Args>
  28.   std::tuple<pvoidary, void*> operator()(Args&&... args) const {
  29.     typedef std::tuple<Lambda, Args...> package;
  30.     void* pVoid = new package(func, std::forward<Args>(args)...);
  31.     return std::make_tuple(
  32.       [](void* pVoid) {
  33.         package* pPack = reinterpret_cast<package*>(pVoid);
  34.         do_call( std::get<0>(*pPack), MakeSeq<sizeof...(Args)+1, 1>(), *pPack );
  35.       },
  36.       pVoid
  37.     );
  38.   }
  39. };
  40. template<typename Lambda>
  41. pvoidary_factory<Lambda> Wrap( Lambda const& func ) {
  42.   return {func};
  43. }
  44.  
  45. int main() {
  46.   int x = 7;
  47.   auto factory = Wrap( [x]( int y, double d ) {
  48.     std::cout << "X:" << x << "Y:" << y << "D:" << d << "\n";
  49.   } );
  50.   void* pvoid;
  51.   pvoidary pfunc; // void(*)(void*)
  52.   std::tie( pfunc, pvoid ) = factory( 10, 3.14 ); // bind y and d here
  53.   pfunc( pvoid ); // calls the wrapped method
  54. }
Success #stdin #stdout 0s 2984KB
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X:7Y:10D:3.14
https://ideone.com/fbR3CQ
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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