Re: Templates and derivation

Lars Jordan wrote:


I have stripped out extras, leaving the minimum. What I have given
compiles successfully, even when using your Holder class. Essentially,
two lines change: the addition of a template operator to template class
MF, and the need for the explicit invocation of this operator to get
the compiler to recognise the conversion.

template<typename T> class MF : public T
{
public:
   template<typename B> operator MF<B>& () { return *this; }
};

class Base
{
public:
   virtual ~Base() { }
};

class Derived : public Base
{
public:
   virtual ~Derived() { }
};

int main( int, char*[] )
{
   MF<Derived>* pMFD = new MF<Derived>;
   MF<Base>* pMFB = &(MF<Base>&)*pMFD;
   return 0;
}

I do not know if it can be done without explicitly invoking a
conversion operator. I hope this is something like what you are
looking for.

Manfred

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