模板奇异递归+扩展方法

#include <iostream>

template<class derived>
struct base
{
    derived getDerivedType(){};
 void interface(){ static_cast<derived*>(this)->interface();};
};

struct derived1:public base<derived1>
{
    using base::getDerivedType;
 void interface()
 {
     std::cout<< "derived1 interface \n";
 }

};
struct derived2:public base<derived2>
{
 void interface()
 {
     std::cout<< "derived2 interface \n";
 }

};

template <class T>
struct interface_t {
    base<T> operator()( base<T>& s) const
    {
        s.interface();
        return s;
    }
};
template<class T>
const interface_t<T> ext_interface ={}; 

template<class T>
base<T> operator|(base<T>& that,interface_t<T> ext)
{
    return ext(that);
}

struct extension_interface
{
    extension_interface& operator-(void)
    {
    return *this;
    }
    template <class T>
    friend const base<T>&  operator >(base<T>& that,extension_interface& ex)
    {
        that.interface();
        return that;
    }
};




int main()
{
    derived1*  d1 = new derived1();
    derived2 d2;
    //d2| ext_interface<decltype(d2.getDerivedType())> ; //boost这种扩展模板类不方便
    d2>-extension_interface(); 
    *d1>-extension_interface();
    return 0;

}