.. Copyright David Abrahams 2006. Distributed under the Boost
.. Software License, Version 1.0. (See accompanying
.. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

``iterator_facade`` is a base class template that implements the
interface of standard iterators in terms of a few core functions
and associated types, to be supplied by a derived iterator class.