passing a writable method

updater.cpp

#include <exception>
#include <iostream>
#include <string>

using namespace std;

struct GetterOfThings
{
    virtual ~GetterOfThings() {}

    virtual string& getWritableName() = 0;
};

struct ThingUpdater
{
    static void update(GetterOfThings& getter, const string& updatedName)
    {
        getter.getWritableName() = updatedName;
    }
};

class Thing : protected virtual GetterOfThings
{
public:
    Thing(const string& name = string()) : m_name(name) {}
    const string& getName() const { return m_name; }

    void update()
    {
        ThingUpdater::update(*this, "updated name");
    }

protected:
    string& getWritableName() { return m_name; }
    // This prevents the compiler from picking up the public method
    // string& getName() { return m_name; }

private:
    string m_name;
};

int
main(int arc, char** argv)
{
    try
    {
        Thing thing;

        cout << "name = " << thing.getName() << endl;
        cout << "updating" << endl;

        thing.update();

        cout << "name = " << thing.getName() << endl;

        return 0;
    }
    catch (const exception& e)
    {
        cerr << "exception in main: " << e.what() << endl;
    }
    catch (...)
    {
        cerr << "unexpected exception in main" << endl;
    }

    return -1;
}