Separate iterator operators from iterator traits?

From: Daryle Walker (darylew_at_[hidden])
Date: 2001-09-03 13:42:56

In <boost/operators.hpp>, we have templates like:

//==========================================================================
template <class T,
          class V,
          class D = std::ptrdiff_t,
          class P = V*,
          class R = V&>
struct bidirectional_iterator_helper
  : equality_comparable1<T
  , unit_steppable<T
  , dereferenceable<T, P
  , boost::iterator<std::bidirectional_iterator_tag, V, D, P, R
    > > > > {};
//==========================================================================

where the operator helpers are attached to the iterator base.  Maybe we can
do a separation like:

//==========================================================================
template <class T, class P, class B = ::boost::detail::empty_base>
struct bidirectional_iterator_operators
    : equality_comparable1<T
    , unit_steppable<T
    , dereferenceable<T, P, B
      > > > {};

//...

template <class T,
          class V,
          class D = std::ptrdiff_t,
          class P = V*,
          class R = V&>
struct bidirectional_iterator_helper
  : bidirectional_iterator_operators <T, P
  , boost::iterator<std::bidirectional_iterator_tag, V, D, P, R
    > > {};
//==========================================================================

in case we need to supply the iterator base in a different manner (like now
when I'm trying to use these operators with an iterator based off a reverse
iterator of another iterator class I defined).

-- 
Daryle Walker
Mac, Internet, and Video Game Junkie
darylew AT mac DOT com