Re: iterator_adaptor const iterator question

From: dave_abrahams (david.abrahams_at_[hidden])
Date: 2002-01-13 22:40:11

--- In Boost-Users_at_y..., Duane Murphy <duanemurphy_at_m...> wrote:
> I have now built a couple of iterators using 
boost::iterator_adaptor.
> These are not adapted iterators but rather iterators developed to 
iterate
> over interfaces that have not iterators.
> 
> I havent found a good example of how to declare the equivalent of a
> const_iterator like in vector. What would the declartion look like?
> 
> If the definition of an iterator is:
> 
> typedef boost::iterator_adaptor< Base, Policy > iterator;
> 
> What would the declartion for a const_iterator look like?

depending on your compiler and requirements, it might look like:

   boost::iterator_adaptor<Base
        , Policy, std::iterator_traits<Base>::value_type const>
   const_iterator;

The library is full of iterator pair generators which generate a 
const/mutable iterator pair. You could look at those for examples.

This paper http://www.boost.org/libs/utility/iterator_adaptors.pdf is 
also helpful in understanding how a constant iterator should be 
declared.

-Dave