Boost C++ Libraries

boost/foreach_fwd.hpp

///////////////////////////////////////////////////////////////////////////////
// foreach.hpp header file
//
// Copyright 2010 Eric Niebler.
// 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)
// See http://www.boost.org/libs/foreach for documentation
//
// Credits:
// Kazutoshi Satoda: for suggesting the need for a _fwd header for foreach's
//                      customization points.

#ifndef BOOST_FOREACH_FWD_HPP
#define BOOST_FOREACH_FWD_HPP

#include <utility> // for std::pair

// This must be at global scope, hence the uglified name
enum boost_foreach_argument_dependent_lookup_hack
{
    boost_foreach_argument_dependent_lookup_hack_value
};

namespace boost
{

namespace foreach
{
    template<typename T>
    std::pair<T, T> in_range(T begin, T end);

    ///////////////////////////////////////////////////////////////////////////////
    // boost::foreach::tag
    //
    typedef boost_foreach_argument_dependent_lookup_hack tag;

    ///////////////////////////////////////////////////////////////////////////////
    // boost::foreach::is_lightweight_proxy
    //   Specialize this for user-defined collection types if they are inexpensive to copy.
    //   This tells BOOST_FOREACH it can avoid the rvalue/lvalue detection stuff.
    template<typename T>
    struct is_lightweight_proxy;

    ///////////////////////////////////////////////////////////////////////////////
    // boost::foreach::is_noncopyable
    //   Specialize this for user-defined collection types if they cannot be copied.
    //   This also tells BOOST_FOREACH to avoid the rvalue/lvalue detection stuff.
    template<typename T>
    struct is_noncopyable;

} // namespace foreach

// Workaround for unfortunate https://svn.boost.org/trac/boost/ticket/6131
namespace BOOST_FOREACH
{
    using foreach::in_range;
    using foreach::tag;

    template<typename T>
    struct is_lightweight_proxy
      : foreach::is_lightweight_proxy<T>
    {};

    template<typename T>
    struct is_noncopyable
      : foreach::is_noncopyable<T>
    {};

} // namespace BOOST_FOREACH

} // namespace boost

#endif