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  1. #include <memory>
  2. #include <functional>
  3.  
  4. //all done assuming interface is `void (*)()`
  5.  
  6. struct function_interface {
  7.     virtual void operator()()=0;
  8.     virtual std::unique_ptr<function_interface> copy()=0;
  9. };
  10. template<class T>
  11. class function_impl : public function_interface  {
  12.     T t;
  13. public:
  14.     function_impl(T t_) : t(std::move(t_)) {};
  15.     void operator()() {t();}
  16.     virtual std::unique_ptr<function_interface> copy()
  17.     {return std::unique_ptr<function_interface>(new function_impl(t));}
  18. };
  19.  
  20. class function {
  21.     std::unique_ptr<function_interface> ptr;
  22. public: 
  23.     template<class T>
  24.     function(T t) : ptr(new function_impl<T>(std::move(t))) {}
  25.     function(const function& rhs) : ptr(rhs.ptr->copy()) {}
  26.     function(function&& rhs) : ptr(std::move(rhs.ptr)) {}
  27.     void operator()() {(*ptr)();}
  28. };
  29.  
  30. #include <iostream>
  31. struct oid {
  32.     void operator()() {std::cout << "oid";}
  33. };
  34. void func() {std::cout << "function";}
  35.  
  36. int main() {
  37.     function a(func);
  38.     function b(a);
  39.     b();    
  40.     function c((oid()));
  41.     c();
  42.     function d(c);
  43.     d();    
  44. }
Success #stdin #stdout 0s 3016KB
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functionoidoid
https://ideone.com/21JUw
language:
C++14 (gcc 8.3)
created:
13 years ago
visibility:
public

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