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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 <iostream>
// back-end
#include <boost/msm/back/state_machine.hpp>
//front-end
#include <boost/msm/front/state_machine_def.hpp>
namespace msm = boost::msm;
namespace mpl = boost::mpl;
using namespace boost::msm::front;
namespace
{
// events
struct event1 {};
// front-end: define the FSM structure
struct my_machine_ : public msm::front::state_machine_def<my_machine_>
{
// The list of FSM states
struct State1 : public msm::front::state<>
{
// every (optional) entry/exit methods get the event passed.
template <class Event,class FSM>
void on_entry(Event const&,FSM& ) {std::cout << "entering: State1" << std::endl;}
template <class Event,class FSM>
void on_exit(Event const&,FSM& ) {std::cout << "leaving: State1" << std::endl;}
};
struct State2 : public msm::front::state<>
{
template <class Event,class FSM>
void on_entry(Event const& ,FSM&) {std::cout << "entering: State2" << std::endl;}
template <class Event,class FSM>
void on_exit(Event const&,FSM& ) {std::cout << "leaving: State2" << std::endl;}
};
struct State3 : public msm::front::state<>
{
// when stopped, the CD is loaded
template <class Event,class FSM>
void on_entry(Event const& ,FSM&) {std::cout << "entering: State3" << std::endl;}
template <class Event,class FSM>
void on_exit(Event const&,FSM& ) {std::cout << "leaving: State3" << std::endl;}
};
struct State4 : public msm::front::state<>
{
template <class Event,class FSM>
void on_entry(Event const&,FSM& ) {std::cout << "entering: State4" << std::endl;}
template <class Event,class FSM>
void on_exit(Event const&,FSM& ) {std::cout << "leaving: State4" << std::endl;}
};
// the initial state of the player SM. Must be defined
typedef State1 initial_state;
// transition actions
void State2ToState3(none const&) { std::cout << "my_machine::State2ToState3\n"; }
void State3ToState4(none const&) { std::cout << "my_machine::State3ToState4\n"; }
// guard conditions
bool always_true(none const& evt)
{
std::cout << "always_true" << std::endl;
return true;
}
bool always_false(none const& evt)
{
std::cout << "always_false" << std::endl;
return false;
}
typedef my_machine_ p; // makes transition table cleaner
// Transition table for player
struct transition_table : mpl::vector<
// Start Event Next Action Guard
// +---------+-------------+---------+---------------------+----------------------+
_row < State1 , none , State2 >,
a_row < State2 , none , State3 , &p::State2ToState3 >,
// +---------+-------------+---------+---------------------+----------------------+
row < State3 , none , State4 , &p::State3ToState4 , &p::always_true >,
g_row < State3 , none , State4 , &p::always_false >,
_row < State4 , event1 , State1 >
// +---------+-------------+---------+---------------------+----------------------+
> {};
// Replaces the default no-transition response.
template <class FSM,class Event>
void no_transition(Event const& e, FSM&,int state)
{
std::cout << "no transition from state " << state
<< " on event " << typeid(e).name() << std::endl;
}
};
// Pick a back-end
typedef msm::back::state_machine<my_machine_> my_machine;
//
// Testing utilities.
//
static char const* const state_names[] = { "State1", "State2", "State3", "State4" };
void pstate(my_machine const& p)
{
std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
}
void test()
{
my_machine p;
// needed to start the highest-level SM. This will call on_entry and mark the start of the SM
// in this case it will also immediately trigger all anonymous transitions
p.start();
// this event will bring us back to the initial state and thus, a new "loop" will be started
p.process_event(event1());
}
}
int main()
{
test();
return 0;
}
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