Re: indirect_iterator_generator<list<shared_ptr<X> >::iterator> again

David Abrahams writes:

Raoul Gough writes: [snip]

...

Really seems a bit weird that boost::referent wasn't already invented in the type_traits portion of the library, since it can be applied to any kind of pointer, iterator, etc... Anyway, it has neatened up my code quite a bit, thanks.

It's a little quirky, yet. If you define an iterator with a nested element_type member it will do the wrong thing.

I guess in an ideal world, we would have something like this: template<typename T> struct handle_traits { typedef typename T::value_type value_type; typedef typename T::pointer_type pointer_type; typedef typename T::reference_type reference_type; }; template<typename T> struct iterator_traits : public handle_traits<T> { typedef typename T::iterator_category iterator_category; typedef typename T::difference_type difference_type; }; Since an iterator is-a handle with additional functionality (i.e. movability to one extent or another). In the case of indirect_iterator<T>, we would need valid instantiations for iterator_traits<T> and handle_traits BTW, does it ever make sense to have pointer_type != (value_type *) or reference_type != (value_type &) ?? -- Raoul Gough "Let there be one measure for wine throughout our kingdom, and one measure for ale, and one measure for corn" - Magna Carta