Test of concept. How to extend API for advanced users (via GetSpell), and hide dangerous functions from beginners.

HogwartAPI.cpp

#include <memory>

//Interface
class IMagician
{
	protected:
		virtual ~IMagician() {};
		typedef void(IMagician::*Spell_t)();
	
	public:
		virtual void Hi() = 0;
		virtual Spell_t GetSpell(const char* spell) = 0;
};

//Advaced usage, typedefs and strings for GetSpell
const char* WingardiumLeviosa_s = "Wingardium Leviosa!";
const char* Accio_s             = "Accio!";

typedef void(IMagician::*WingardiumLeviosa_t)();
typedef bool(IMagician::*Accio_t)(const char* what);

//IMPLEMENTATION
class HogwartMagician : public IMagician
{
	public:
		virtual ~HogwartMagician() {}
		virtual void Hi();
		IMagician::Spell_t GetSpell(const char* spell);
	private:
		void WingardiumLeviosa();
		bool Accio(const char* what);
};

IMagician* CreateMagician()
{
	return new HogwartMagician();
}

void DestroyMagician(IMagician* p_magician)
{
	delete dynamic_cast<HogwartMagician*>(p_magician);
}

HogwartMagician::Spell_t HogwartMagician::GetSpell(const char* spell)
{
	if (spell == "Accio!") 
		return (Spell_t)(&HogwartMagician::Accio);
	
	if (spell == "Wingardium Leviosa!")
		return (Spell_t)(&HogwartMagician::WingardiumLeviosa);

	return nullptr;
}

void HogwartMagician::Hi()			{ printf("Hi! \n"); }
void HogwartMagician::WingardiumLeviosa()	{ printf("Everything is flying! \n"); }
bool HogwartMagician::Accio(const char* what)	{ printf("I want %s \n", what); return 1; }

int main()
{
	std::shared_ptr<IMagician> me(CreateMagician(),DestroyMagician);

	WingardiumLeviosa_t Say_WingardiumLeviosa = (WingardiumLeviosa_t)me->GetSpell(WingardiumLeviosa_s);
	Accio_t             Say_Accio             = (Accio_t)            me->GetSpell(Accio_s);
	
	auto meAdv = me.get();
	(meAdv->*Say_Accio)("Book");
	(meAdv->*Say_WingardiumLeviosa)();

	return 0;
}