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  1. #include <iostream>
  2. #include <memory>
  3. #include <utility>
  4. #include <vector>
  5. #include <algorithm>
  6.  
  7. template <typename Signature>
  8. struct delegate;
  9.  
  10. template <typename... Args>
  11. struct delegate<void(Args...)>
  12. {
  13.     struct base {
  14.         virtual ~base() {}
  15.         virtual bool do_cmp(base* other) = 0;
  16.         virtual void do_call(Args... args) = 0;
  17.     };
  18.     template <typename T>
  19.     struct call: base {
  20.         T d_callback;
  21.         template <typename S>
  22.         call(S&& callback): d_callback(std::forward<S>(callback)) {}
  23.  
  24.         bool do_cmp(base* other) {
  25.             call<T>* tmp = dynamic_cast<call<T>*>(other);
  26.             return tmp && this->d_callback == tmp->d_callback;
  27.         }
  28.         void do_call(Args... args) {
  29.             return this->d_callback(std::forward<Args>(args)...);
  30.         }
  31.     };
  32.     std::vector<std::unique_ptr<base>> d_callbacks;
  33.  
  34.     delegate(delegate const&) = delete;
  35.     void operator=(delegate const&) = delete;
  36. public:
  37.     delegate() {}
  38.     template <typename T>
  39.     delegate& operator+= (T&& callback) {
  40.         this->d_callbacks.emplace_back(new call<T>(std::forward<T>(callback)));
  41.         return *this;
  42.     }
  43.     template <typename T>
  44.     delegate& operator-= (T&& callback) {
  45.         call<T> tmp(std::forward<T>(callback));
  46.         auto it = std::remove_if(this->d_callbacks.begin(),
  47.                                  this->d_callbacks.end(),
  48.                                  [&](std::unique_ptr<base>& other) {
  49.                                      return tmp.do_cmp(other.get());
  50.                                  });
  51.         this->d_callbacks.erase(it, this->d_callbacks.end());
  52.         return *this;
  53.     }
  54.  
  55.     void operator()(Args... args) {
  56.         for (auto& callback: this->d_callbacks) {
  57.             callback->do_call(args...);
  58.         }
  59.     }
  60. };
  61.  
  62. // ----------------------------------------------------------------------------
  63.  
  64. template <typename RC, typename Class, typename... Args>
  65. class member_call {
  66.     Class* d_object;
  67.     RC (Class::*d_member)(Args...);
  68. public:
  69.     member_call(Class* object, RC (Class::*member)(Args...))
  70.         : d_object(object)
  71.         , d_member(member) {
  72.     }
  73.     RC operator()(Args... args) {
  74.         return (this->d_object->*this->d_member)(std::forward<Args>(args)...);
  75.     }
  76.     bool operator== (member_call const& other) const {
  77.         return this->d_object == other.d_object
  78.             && this->d_member == other.d_member;
  79.     }
  80.     bool operator!= (member_call const& other) const {
  81.         return !(*this == other);
  82.     }
  83. };
  84.  
  85. template <typename RC, typename Class, typename... Args>
  86. member_call<RC, Class, Args...> mem_call(Class& object,
  87.                                          RC     (Class::*member)(Args...)) {
  88.     return member_call<RC, Class, Args...>(&object, member);
  89. }
  90.  
  91. // ----------------------------------------------------------------------------
  92.  
  93. void foobar(int number) { std::cout << "foobar(" << number << ")\n"; }
  94.  
  95. // ----------------------------------------------------------------------------
  96.  
  97. int main()
  98. {
  99. 	delegate<void(int)> testDel;
  100.  
  101. 	testDel += foobar;
  102.  
  103. 	testDel(5);
  104. }
Success #stdin #stdout 0s 3476KB
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Standard input is empty
stdout
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foobar(5)
https://ideone.com/G4Yybr
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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