Sandbox/Bind.cpp

   1 #include "Bind.h"
   2
   3 #include <iostream>
   4 #include <functional>
   5 using namespace std;
   6
   7 // https://en.cppreference.com/w/cpp/utility/functional/bind
   8 // Ep 15: https://www.youtube.com/watch?v=JtUZmkvroKg & https://www.youtube.com/watch?v=ZlHi8txU4aQ
   9
  10 namespace Bind
  11 {
  12     template <typename T>
  13     void print(T i, const string& s)
  14     {
  15         cout << i << ' ' << s << endl;
  16     }
  17
  18     void bind()
  19     {
  20         int i = 5;
  21
  22         // The given function must be a concrete one (the generic parameter of 'print' must be specified in this case).
  23         // 'ref' is to create a standard reference to 'i'.
  24         // the second parameter create a parameter in the new created function.
  25         // 'bind' were originaly from the Boost library.
  26         const auto f = bind(&print<int>, ref(i), placeholders::_1);
  27
  28         f("Hello");
  29
  30         i = 6;
  31         f(", World");
  32
  33         function<void(const string&)> f2(f); // Create a 'std::function'.
  34         i = 7;
  35         f2("!");
  36     }
  37
  38     // Prefer lambdas instead of bind.
  39     void lambda()
  40     {
  41         // Swapping arguments.
  42         const auto f = [](auto&& arg1, auto&& arg2)
  43         {
  44             // Perfect forwarding (not necessary).
  45             print(forward<decltype(arg2)>(arg2), forward<decltype(arg1)>(arg1));
  46         };
  47
  48         f("Hello", 42);
  49     }
  50 }
  51
  52 void Bind::tests()
  53 {
  54     Bind::bind();
  55     cout << "-----" << endl;
  56     Bind::lambda();
  57 }