instance_eval.cc

#include <iostream>
#include <functional>

using namespace std;

class Object
{
  friend int main();
public:
  Object(string data) : _data(data) {}

  void instance_eval(function<void(Object*)> block)
  {
    block(this);
  }
private:
  string _data;
};

int main()
{
  Object obj("SECRET"), obj2("DATA");

  auto block = [](Object *_this){ cout << _this->_data << endl; };

  obj.instance_eval( block );
  obj2.instance_eval( block );
}