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- // Copyright 2010 Christophe Henry
- // henry UNDERSCORE christophe AT hotmail DOT com
- // This is an extended version of the state machine available in the boost::mpl library
- // Distributed under the same license as the original.
- // Copyright for the original version:
- // Copyright 2005 David Abrahams and Aleksey Gurtovoy. 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)
- #include <vector>
- #include <iostream>
- #include <boost/phoenix/phoenix.hpp>
- // add phoenix support in eUML
- #define BOOST_MSM_EUML_PHOENIX_SUPPORT
- #include <boost/msm/back/state_machine.hpp>
- #include <boost/msm/front/euml/euml.hpp>
- using namespace std;
- using namespace boost::msm::front::euml;
- namespace msm = boost::msm;
- using namespace boost::phoenix;
- // entry/exit/action/guard logging functors
- #include "logging_functors.h"
- namespace // Concrete FSM implementation
- {
- // events
- BOOST_MSM_EUML_EVENT(end_pause)
- BOOST_MSM_EUML_EVENT(stop)
- BOOST_MSM_EUML_EVENT(pause)
- BOOST_MSM_EUML_EVENT(open_close)
- struct play_event : boost::msm::front::euml::euml_event<play_event>
- {
- };
- play_event play;
- enum DiskTypeEnum
- {
- DISK_CD=0,
- DISK_DVD=1
- };
- // A "complicated" event type that carries some data.
- struct cd_detected_event : boost::msm::front::euml::euml_event<cd_detected_event>
- {
- cd_detected_event(){}
- cd_detected_event(std::string const& name,DiskTypeEnum disk):cd_name(name),cd_type(disk){}
- std::string cd_name;
- DiskTypeEnum cd_type;
- };
- // define an instance for a nicer transition table
- cd_detected_event cd_detected;
- // Concrete FSM implementation
- // The list of FSM states
- // state not needing any entry or exit
- BOOST_MSM_EUML_STATE((),Paused)
- // states with standard eUML actions
- BOOST_MSM_EUML_STATE(( Stopped_Entry,Stopped_Exit ),Stopped)
- BOOST_MSM_EUML_STATE(( Playing_Entry,Playing_Exit ),Playing)
- // a "standard" msm state
- struct Empty_impl : public msm::front::state<> , public euml_state<Empty_impl>
- {
- // this allows us to add some functions
- void foo() {std::cout << "Empty::foo " << std::endl;}
- // standard entry behavior
- template <class Event,class FSM>
- void on_entry(Event const& evt,FSM& fsm)
- {
- std::cout << "entering: Empty" << std::endl;
- }
- template <class Event,class FSM>
- void on_exit(Event const& evt,FSM& fsm)
- {
- std::cout << "leaving: Empty" << std::endl;
- }
- };
- //instance for use in the transition table
- Empty_impl const Empty;
- // entry and exit actions as phoenix functions
- struct open_entry_impl
- {
- typedef void result_type;
- void operator()()
- {
- cout << "entering: Open" << endl;
- }
- };
- boost::phoenix::function<open_entry_impl> open_entry;
- struct open_exit_impl
- {
- typedef void result_type;
- void operator()()
- {
- cout << "leaving: Open" << endl;
- }
- };
- boost::phoenix::function<open_exit_impl> open_exit;
- // a state using phoenix for entry/exit actions
- BOOST_MSM_EUML_STATE(( open_entry(),open_exit() ),Open)
- // actions and guards using boost::phoenix
- struct start_playback_impl
- {
- typedef void result_type;
- void operator()()
- {
- cout << "calling: start_playback" << endl;
- }
- };
- boost::phoenix::function<start_playback_impl> start_playback;
- // a guard taking the event as argument
- struct good_disk_format_impl
- {
- typedef bool result_type;
- template <class Event>
- bool operator()(Event const& evt)
- {
- // to test a guard condition, let's say we understand only CDs, not DVD
- if (evt.cd_type!=DISK_CD)
- {
- std::cout << "wrong disk, sorry" << std::endl;
- return false;
- }
- std::cout << "good disk" << std::endl;
- return true;
- }
- };
- boost::phoenix::function<good_disk_format_impl> good_disk_format;
- // a simple action
- struct store_cd_info_impl
- {
- typedef void result_type;
- void operator()()
- {
- cout << "calling: store_cd_info" << endl;
- }
- };
- boost::phoenix::function<store_cd_info_impl> store_cd_info;
- // an action taking the fsm as argument and sending it a new event
- struct process_play_impl
- {
- typedef void result_type;
- template <class Fsm>
- void operator()(Fsm& fsm)
- {
- cout << "queuing a play event" << endl;
- fsm.process_event(play);
- }
- };
- // it is also possible to use BOOST_PHOENIX_ADAPT_CALLABLE to avoid defining a global variable
- BOOST_PHOENIX_ADAPT_CALLABLE(process_play, process_play_impl, 1)
-
- // transition table. Actions and guards are written as phoenix functions
- BOOST_MSM_EUML_TRANSITION_TABLE((
- //an action without arguments
- Playing == Stopped + play / start_playback() ,
- Playing == Paused + end_pause ,
- // +------------------------------------------------------------------------------+
- Empty == Open + open_close ,
- // +------------------------------------------------------------------------------+
- Open == Empty + open_close ,
- Open == Paused + open_close ,
- Open == Stopped + open_close ,
- Open == Playing + open_close ,
- // +------------------------------------------------------------------------------+
- Paused == Playing + pause ,
- // +------------------------------------------------------------------------------+
- Stopped == Playing + stop ,
- Stopped == Paused + stop ,
- // a guard taking the event as argument
- // and an action made of a phoenix expression of 2 actions
- // _event is a placeholder for the current event
- // _fsm is a placeholder for the current state machine
- Stopped == Empty + cd_detected [good_disk_format(_event)]
- / (store_cd_info(),process_play(_fsm)),
- Stopped == Stopped + stop
- // +------------------------------------------------------------------------------+
- ),transition_table)
- // create a state machine "on the fly"
- BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
- init_ << Empty, // Init State
- no_action, // Entry
- no_action, // Exit
- attributes_ << no_attributes_, // Attributes
- configure_ << no_configure_, // configuration
- Log_No_Transition // no_transition handler
- ),
- player_) //fsm name
- // or simply, if no no_transition handler needed:
- //BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
- // Empty // Init State
- // ),player_)
- // choice of back-end
- typedef msm::back::state_machine<player_> player;
- //
- // Testing utilities.
- //
- static char const* const state_names[] = { "Stopped", "Paused", "Open", "Empty", "Playing" };
- void pstate(player const& p)
- {
- std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
- }
- void test()
- {
- player p;
- // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
- p.start();
- // go to Open, call on_exit on Empty, then action, then on_entry on Open
- p.process_event(open_close); pstate(p);
- p.process_event(open_close); pstate(p);
- // will be rejected, wrong disk type
- p.process_event(
- cd_detected_event("louie, louie",DISK_DVD)); pstate(p);
- p.process_event(
- cd_detected_event("louie, louie",DISK_CD)); pstate(p);
- // no need to call play as the previous event does it in its action method
- //p.process_event(play);
- // at this point, Play is active
- p.process_event(pause); pstate(p);
- // go back to Playing
- p.process_event(end_pause); pstate(p);
- p.process_event(pause); pstate(p);
- p.process_event(stop); pstate(p);
- // event leading to the same state
- // no action method called as none is defined in the transition table
- p.process_event(stop); pstate(p);
- // test call to no_transition
- p.process_event(pause); pstate(p);
- }
- }
- int main()
- {
- test();
- return 0;
- }
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