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  1. #include <functional>
  2. #include <vector>
  3. #include <iostream>
  4. #include <memory>
  5.  
  6. template < typename CB > struct event
  7. {
  8.     std::vector< std::function<CB> > call_back ;
  9.  
  10.     template < typename FN > event<CB>& operator+= ( FN fn )
  11.     {
  12.        call_back.emplace_back(fn) ;
  13.        return *this ;
  14.     }
  15.  
  16. };
  17.  
  18. struct test
  19. {
  20.     const std::string& name() const { return name_ ; }
  21.  
  22.     void name( const std::string& new_name )
  23.     { name_ = new_name ; fire_name_changed() ; }
  24.  
  25.     event< void( const test&, const std::string& ) > name_changed ;
  26.  
  27.     template < typename FN, typename... ARGS > void subscribe( FN fn, ARGS&&... args )
  28.     {
  29.         using namespace std::placeholders ;
  30.         name_changed.call_back.emplace_back( std::bind( fn, args..., _1, _2 ) ) ;
  31.     }
  32.  
  33.     private:
  34.  
  35.          std::string name_ = "anonymous" ;
  36.  
  37.          void fire_name_changed()
  38.          { for( const auto& f : name_changed.call_back ) f( *this, name() ) ; }
  39. };
  40.  
  41. void a_function( const test& sender, const std::string& value )
  42. {
  43.     std::cout << "a_function: -\n    name of object at "
  44.                << std::addressof(sender) << "  changed to: '" << value << "'\n\n" ;
  45. }
  46.  
  47. void another_fun( const std::string& msg, const test& sender, const std::string& value )
  48. {
  49.     std::cout << "another_fun: -\n    msg: '" << msg
  50.                << "'\n    sender: " << std::addressof(sender)
  51.                << "\n    value: '" << value << "'\n\n" ;
  52. }
  53.  
  54. int main()
  55. {
  56.     test t ;
  57.     t.name_changed += []( const test& sender, const std::string& value )
  58.                       {
  59.                           std::cout << "lambda: -\n    name of object at "
  60.                                      << std::addressof(sender)
  61.                                      << "  changed to: '" << value << "'\n\n" ;
  62.                       } ;
  63.  
  64.     t.name_changed += a_function ;
  65.  
  66.     t.subscribe( another_fun, "**** name of object is changed! ****" ) ;
  67.  
  68.     struct recvr
  69.     {
  70.         void handle_it( const test& sender, const std::string& value ) const
  71.                       {
  72.                           std::cout << "recvr::handle_it -\n    name of object at "
  73.                                      << std::addressof(sender)
  74.                                      << "  changed to: '" << value << "'\n\n" ;
  75.                       }
  76.     };
  77.  
  78.     recvr r ;
  79.     t.subscribe( &recvr::handle_it, r ) ;
  80.  
  81.     t.name( "Cambalinho" ) ; // change the name to test it
  82. }
  83.  
Success #stdin #stdout 0s 3480KB
comments (?)
stdin
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Standard input is empty
stdout
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lambda: -
    name of object at 0xbfb05f70  changed to: 'Cambalinho'

a_function: -
    name of object at 0xbfb05f70  changed to: 'Cambalinho'

another_fun: -
    msg: '**** name of object is changed! ****'
    sender: 0xbfb05f70
    value: 'Cambalinho'

recvr::handle_it -
    name of object at 0xbfb05f70  changed to: 'Cambalinho'
https://ideone.com/OBmXFf
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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