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  1. #include <iostream>
  2. #include <functional>
  3. #include <string>
  4.  
  5. namespace fx {
  6.     template<int I> struct placeholder{};
  7. }
  8.  
  9. namespace std{
  10.     template<int I>
  11.     struct is_placeholder< ::fx::placeholder<I>> : std::integral_constant<int, I>{};
  12. }
  13.  
  14. namespace fx {
  15.     template <size_t... Is>
  16.     struct indices {};
  17.  
  18.     template <size_t N, std::size_t... Is>
  19.     struct build_indices : build_indices<N-1, N-1, Is...> {};
  20.  
  21.     template <size_t... Is>
  22.     struct build_indices<0, Is...> : indices<Is...> {};
  23.  
  24.     template<std::size_t... Is, class F, class... Args>
  25.     auto easy_bind(indices<Is...>, F const& f, Args&&... args)
  26.     -> decltype(std::bind(f, std::forward<Args>(args)..., placeholder<Is + 1>{}...))
  27.     {
  28.         return std::bind(f, std::forward<Args>(args)..., placeholder<Is + 1>{}...);
  29.     }
  30.  
  31.     template<class R, class... FArgs, class... Args>
  32.     auto easy_bind(std::function<R(FArgs...)> f, Args&&... args)
  33.     -> decltype(fx::easy_bind(build_indices<sizeof...(FArgs) - sizeof...(Args)>{}, f, std::forward<Args>(args)...)) {
  34.     return fx::easy_bind(build_indices<sizeof...(FArgs) - sizeof...(Args)>{}, f, std::forward<Args>(args)...);
  35.     }
  36.  
  37.     template<class R, class... FArgs, class... Args>
  38.     auto easy_bind(R (*f)(FArgs...), Args&&... args)
  39.     -> decltype(fx::easy_bind(build_indices<sizeof...(FArgs) - sizeof...(Args)>{}, f, std::forward<Args>(args)...)) {
  40.     	return fx::easy_bind(build_indices<sizeof...(FArgs) - sizeof...(Args)>{}, f, std::forward<Args>(args)...);
  41.     }
  42.  
  43.     template <typename R, typename T, typename... FArgs, typename... Args>
  44. 	auto easy_bind(R (T::*mf)(FArgs...), Args&&... args)
  45. 	-> decltype(fx::easy_bind(std::function<R(T*,FArgs...)>(mf), args...))
  46. 	{
  47. 	    return fx::easy_bind(std::function<R(T*,FArgs...)>(mf), args...);
  48. 	}
  49.  
  50. }
  51.  
  52. //Test Case:
  53. struct SomeStruct {
  54.     void function(int x, float y, std::string str) {
  55.         std::cout << x << " " << y << " " << str << std::endl;    
  56.     }
  57. };
  58.  
  59.  
  60. int main() {
  61. 	auto f = fx::easy_bind(&SomeStruct::function, new SomeStruct);
  62. 	f(5,2.5,"test");
  63.  
  64.     return 0;
  65. }
Success #stdin #stdout 0s 3432KB
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5 2.5 test
https://ideone.com/FtkVBg
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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