boost_iterator/include/boost/iterator/interoperable.hpp

// (C) Copyright David Abrahams 2002.
// (C) Copyright Jeremy Siek    2002.
// (C) Copyright Thomas Witt    2002.
// 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)
#ifndef BOOST_INTEROPERABLE_23022003THW_HPP
# define BOOST_INTEROPERABLE_23022003THW_HPP

# include <boost/iterator/detail/type_traits/disjunction.hpp>

namespace boost {
namespace iterators {

  //
  // Meta function that determines whether two
  // iterator types are considered interoperable.
  //
  // Two iterator types A,B are considered interoperable if either
  // A is convertible to B or vice versa.
  // This interoperability definition is in sync with the
  // standards requirements on constant/mutable container
  // iterators (23.1 [lib.container.requirements]).
  //
  // For compilers that don't support is_convertible
  // is_interoperable gives false positives. See comments
  // on operator implementation for consequences.
  //
  template <typename A, typename B>
  struct is_interoperable
    : detail::disjunction<std::is_convertible<A, B>, std::is_convertible<B, A>>
  {
  };

} // namespace iterators

using iterators::is_interoperable;

} // namespace boost

#endif // BOOST_INTEROPERABLE_23022003THW_HPP