#include <iostream>
#include <string>
#include <functional>

class Foo
{
  public:

    Foo () = default;
    ~Foo () = default;

    void set (const std::string & v)
    {
        value = v;
    }

    void set ()
    {
        lambda = [](Foo* self)
        {
            return self->value;
        };
    }

    std::string get ()
    {
        return lambda(this);
    }


    std::string value;
    std::function <std::string (Foo*)> lambda;
};

int main ()
{
    Foo foo;

    foo.set ();
    foo.set ("first");

    std::cerr << foo.get () << std::endl; // prints "first"

    foo.set ("captures change");

    std::cerr << foo.get () << std::endl; // prints "captures change"

    Foo foo2 (foo);
    foo2.set ("second");

    std::cerr << foo.get () << std::endl; // prints "captures change" (as desired)
    std::cerr << foo2.get () << std::endl; // prints "captures change" (I would want "second" here)

    return 0;
}