Re: iterator adaptor and pure virutal classes

From: rogeeff (rogeeff_at_[hidden])
Date: 2001-12-14 19:26:47

--- In boost_at_y..., "David Abrahams" <david.abrahams_at_r...> wrote:
> 
> ----- Original Message -----
> From: "rogeeff" <rogeeff_at_m...>
> 
> >
> > int main()
> > {
> >     std::list<A*> lst;
> >
> >     // ... populate lst
> >
> >     typedef
> > boost::indirect_iterator_generator<std::list<A*>::iterator,A>
> > generator;
> >
> >     generator::type it = lst.begin();
> 
> generator::type it(lst.begin());
> 
> >
> >     it->foo();
> >
> >     return 0;
> > }
> >
> > I can't compile this example.
> 
> Next time, please give the reader some clue by posting at least one 
of the
> error messages ;-)
> 
> -Dave

I thought you would deduce from the example.

Here first error that gives me MSVC:
... \boost_1_25_0\boost\type_traits\conversion_traits.hpp(61) : error 
C2259: 'A' : cannot instantiate abstract class due to following 
members:

I played with it a bit. But I still can't overcome compiler attempts 
to instantiate class A. For example, iterator_adaptor::operator[] 
need value_type to be non-abstract.

Gennadiy.