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Re: nested templates and partial specialization

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On 11/12/2011 02:07 PM, ld wrote:
> But it is not anymore a specialization for B<T>  but just T, that is
> why it works. Assume that another class C<T>  wants to specialize it
> too. How does it make the difference? Moreover, in this case, typename
> and class have the same meaning (not always the case though).

Yes, right, sorry.

Actually I think you are trying a member specialisation by a weird
specialisation of the class (just the method, not whole class). It
works with sfinae, but not for virtual methods, and I am not sure
about partial class specialisations.

The below uses inheritance to get the example working - I don't know
if this fits your usage, but inheritance is one way of doing such
things.

Edek

// type declaration
template <typename T, typename I>
struct E; // line 3

// abstract class
struct D {
   virtual void doit() const = 0;
};

template <class T, class TT> struct helper {
     void doitInternal (T const&) const;
};


// partial specialization
template <class T>
struct E<T, D>  : public helper<T,D> {
   virtual void doit() const;

   explicit E(T = T());
   T& e;
};



// simple class
struct A {
   void doit() const;
   int a;
};

// template class
template <typename T>
struct B {
   void doit() const;
   T b;
};

// specialization with class, ok
template <>
void E<A, D>::doit() const
{
   e.doit();
}

template <class T>
struct helper<B<T>, D> {
     void doitInternal (B<T> const&) const;
};

template <class T>
void E<T, D>::doit() const
{
    doitInternal(e);
}

template <class T, class TT>
void helper<T,TT>::doitInternal(T const&) const {}

template <class T>
void helper<B<T>, D>::doitInternal(B<T> const& e) const // line 43
{
   // for B<T>
   e.doit();
}

	

int main() {
   E<A, D> a;
   E<B<int>, D> b;
}

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nested templates and partial specialization ld <laurent.deniau@gmail.com> - 2011-11-11 15:45 -0800
  Re: nested templates and partial specialization ld <laurent.deniau@gmail.com> - 2011-11-11 23:41 -0800
    Re: nested templates and partial specialization Edek <edek.pienkowski@gmail.com> - 2011-11-12 10:16 +0100
      Re: nested templates and partial specialization ld <laurent.deniau@gmail.com> - 2011-11-12 03:33 -0800
        Re: nested templates and partial specialization Edek <edek.pienkowski@gmail.com> - 2011-11-12 13:52 +0100
          Re: nested templates and partial specialization ld <laurent.deniau@gmail.com> - 2011-11-12 05:03 -0800
        Re: nested templates and partial specialization Edek <edek.pienkowski@gmail.com> - 2011-11-12 14:02 +0100
          Re: nested templates and partial specialization ld <laurent.deniau@gmail.com> - 2011-11-12 05:07 -0800
            Re: nested templates and partial specialization Edek <edek.pienkowski@gmail.com> - 2011-11-12 16:18 +0100

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