#ifndef BOOST_STATECHART_RESULT_HPP_INCLUDED

#define BOOST_STATECHART_RESULT_HPP_INCLUDED

//////////////////////////////////////////////////////////////////////////////

// Copyright 2002-2006 Andreas Huber Doenni

// Distributed under the Boost Software License, Version 1.0. (See accompany-

// ing file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

//////////////////////////////////////////////////////////////////////////////

#include <boost/assert.hpp>

namespace boost

{

namespace statechart

{

namespace detail

{

//////////////////////////////////////////////////////////////////////////////

enum reaction_result

{

  no_reaction,

  do_forward_event,

  do_discard_event,

  do_defer_event,

  consumed

};

struct result_utility;

//////////////////////////////////////////////////////////////////////////////

class safe_reaction_result

{

  public:

    //////////////////////////////////////////////////////////////////////////

    safe_reaction_result( const safe_reaction_result & other ) :

      reactionResult( other.reactionResult )

    {

      // This assert fails when an attempt is made to make multiple copies of

      // a result value. This makes little sense, given the requirement that

      // an obtained result value must be returned out of the react function.

      BOOST_ASSERT( reactionResult != consumed );

      other.reactionResult = consumed;

    }

    ~safe_reaction_result()

    {

      // This assert fails when an obtained result value is not returned out

      // of the react() function. This can happen if the user accidentally

      // makes more than one call to reaction functions inside react() or

      // accidentally makes one or more calls to reaction functions outside

      // react()

      BOOST_ASSERT( reactionResult == consumed );

    }

  private:

    //////////////////////////////////////////////////////////////////////////

    safe_reaction_result( reaction_result reactionResult ) :

      reactionResult( reactionResult )

    {

    }

    operator reaction_result() const

    {

      const reaction_result val = reactionResult;

      reactionResult = consumed;

      return val;

    }

    safe_reaction_result & operator=( const safe_reaction_result & );

    mutable reaction_result reactionResult;

    friend struct result_utility;

};

} // namespace detail

#ifdef NDEBUG

  typedef detail::reaction_result result;

#else

  typedef detail::safe_reaction_result result;

#endif

namespace detail

{

//////////////////////////////////////////////////////////////////////////////

struct result_utility

{

  static ::boost::statechart::result make_result( reaction_result value )

  {

    return value;

  }

  static reaction_result get_result( ::boost::statechart::result value )

  {

    return value;

  }

};

} // namespace detail

} // namespace statechart

} // namespace boost

#endif