sl@0: #ifndef BOOST_STATECHART_TRANSITION_HPP_INCLUDED
sl@0: #define BOOST_STATECHART_TRANSITION_HPP_INCLUDED
sl@0: //////////////////////////////////////////////////////////////////////////////
sl@0: // Copyright 2002-2006 Andreas Huber Doenni
sl@0: // Distributed under the Boost Software License, Version 1.0. (See accompany-
sl@0: // ing file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
sl@0: //////////////////////////////////////////////////////////////////////////////
sl@0: 
sl@0: 
sl@0: 
sl@0: #include <boost/statechart/result.hpp>
sl@0: 
sl@0: #include <boost/mpl/if.hpp>
sl@0: 
sl@0: #include <boost/cast.hpp> // boost::polymorphic_downcast
sl@0: #include <boost/type_traits/is_same.hpp>
sl@0: 
sl@0: 
sl@0: 
sl@0: namespace boost
sl@0: {
sl@0: namespace statechart
sl@0: {
sl@0: namespace detail
sl@0: {
sl@0: 
sl@0: 
sl@0: 
sl@0: //////////////////////////////////////////////////////////////////////////////
sl@0: template< class Event >
sl@0: struct no_context
sl@0: {
sl@0:   void no_function( const Event & );
sl@0: };
sl@0: 
sl@0: 
sl@0: 
sl@0: } // namespace detail
sl@0: 
sl@0: 
sl@0: 
sl@0: class event_base;
sl@0: 
sl@0: //////////////////////////////////////////////////////////////////////////////
sl@0: template< class Event, class Destination,
sl@0:           class TransitionContext = detail::no_context< Event >,
sl@0:           void ( TransitionContext::*pTransitionAction )( const Event & ) =
sl@0:             &detail::no_context< Event >::no_function >
sl@0: class transition
sl@0: {
sl@0:   private:
sl@0:     //////////////////////////////////////////////////////////////////////////
sl@0:     struct react_without_transition_action_impl
sl@0:     {
sl@0:       template< class State, class EventBase >
sl@0:       static detail::reaction_result react( State & stt, const EventBase & )
sl@0:       {
sl@0:         return detail::result_utility::get_result(
sl@0:           stt.template transit< Destination >() );
sl@0:       }
sl@0:     };
sl@0: 
sl@0:     struct react_base_with_transition_action_impl
sl@0:     {
sl@0:       template< class State, class EventBase >
sl@0:       static detail::reaction_result react(
sl@0:         State & stt, const EventBase & toEvent )
sl@0:       {
sl@0:         return detail::result_utility::get_result(
sl@0:           stt.template transit< Destination >( pTransitionAction, toEvent ) );
sl@0:       }
sl@0:     };
sl@0: 
sl@0:     struct react_base
sl@0:     {
sl@0:       template< class State, class EventBase, class IdType >
sl@0:       static detail::reaction_result react(
sl@0:         State & stt, const EventBase & evt, const IdType & )
sl@0:       {
sl@0:         typedef typename mpl::if_<
sl@0:           is_same< TransitionContext, detail::no_context< Event > >,
sl@0:           react_without_transition_action_impl,
sl@0:           react_base_with_transition_action_impl
sl@0:         >::type impl;
sl@0:         return impl::react( stt, evt );
sl@0:       }
sl@0:     };
sl@0: 
sl@0:     struct react_derived_with_transition_action_impl
sl@0:     {
sl@0:       template< class State, class EventBase >
sl@0:       static detail::reaction_result react(
sl@0:         State & stt, const EventBase & toEvent )
sl@0:       {
sl@0:         return detail::result_utility::get_result(
sl@0:           stt.template transit< Destination >(
sl@0:             pTransitionAction,
sl@0:             *polymorphic_downcast< const Event * >( &toEvent ) ) );
sl@0:       }
sl@0:     };
sl@0: 
sl@0:     struct react_derived
sl@0:     {
sl@0:       template< class State, class EventBase, class IdType >
sl@0:       static detail::reaction_result react(
sl@0:         State & stt, const EventBase & evt, const IdType & eventType )
sl@0:       {
sl@0:         if ( eventType == Event::static_type() )
sl@0:         {
sl@0:           typedef typename mpl::if_<
sl@0:             is_same< TransitionContext, detail::no_context< Event > >,
sl@0:             react_without_transition_action_impl,
sl@0:             react_derived_with_transition_action_impl
sl@0:           >::type impl;
sl@0:           return impl::react( stt, evt );
sl@0:         }
sl@0:         else
sl@0:         {
sl@0:           return detail::no_reaction;
sl@0:         }
sl@0:       }
sl@0:     };
sl@0: 
sl@0:   public:
sl@0:     //////////////////////////////////////////////////////////////////////////
sl@0:     // The following declarations should be private.
sl@0:     // They are only public because many compilers lack template friends.
sl@0:     //////////////////////////////////////////////////////////////////////////
sl@0:     template< class State, class EventBase, class IdType >
sl@0:     static detail::reaction_result react(
sl@0:       State & stt, const EventBase & evt, const IdType & eventType )
sl@0:     {
sl@0:       typedef typename mpl::if_<
sl@0:         is_same< Event, event_base >, react_base, react_derived
sl@0:       >::type impl;
sl@0: 
sl@0:       return impl::react( stt, evt, eventType );
sl@0:     }
sl@0: };
sl@0: 
sl@0: 
sl@0: 
sl@0: } // namespace statechart
sl@0: } // namespace boost
sl@0: 
sl@0: 
sl@0: 
sl@0: #endif