1 // Copyright 2010 Christophe Henry
2 // henry UNDERSCORE christophe AT hotmail DOT com
3 // This is an extended version of the state machine available in the boost::mpl library
4 // Distributed under the same license as the original.
5 // Copyright for the original version:
6 // Copyright 2005 David Abrahams and Aleksey Gurtovoy. Distributed
7 // under the Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at
9 // http://www.boost.org/LICENSE_1_0.txt)
10
11 #include <iostream>
12 // back-end
13 #include <boost/msm/back/state_machine.hpp>
14 //front-end
15 #include <boost/msm/front/state_machine_def.hpp>
16
17 namespace msm = boost::msm;
18 namespace mpl = boost::mpl;
19 using namespace boost::msm::front;
20
21 namespace
22 {
23 // events
24 struct event1 {};
25
26
27 // front-end: define the FSM structure
28 struct my_machine_ : public msm::front::state_machine_def<my_machine_>
29 {
30 // The list of FSM states
31 struct State1 : public msm::front::state<>
32 {
33 // every (optional) entry/exit methods get the event passed.
34 template <class Event,class FSM>
on_entry__anon30fd97320111::my_machine_::State135 void on_entry(Event const&,FSM& ) {std::cout << "entering: State1" << std::endl;}
36 template <class Event,class FSM>
on_exit__anon30fd97320111::my_machine_::State137 void on_exit(Event const&,FSM& ) {std::cout << "leaving: State1" << std::endl;}
38 };
39 struct State2 : public msm::front::state<>
40 {
41 template <class Event,class FSM>
on_entry__anon30fd97320111::my_machine_::State242 void on_entry(Event const& ,FSM&) {std::cout << "entering: State2" << std::endl;}
43 template <class Event,class FSM>
on_exit__anon30fd97320111::my_machine_::State244 void on_exit(Event const&,FSM& ) {std::cout << "leaving: State2" << std::endl;}
45 };
46
47 struct State3 : public msm::front::state<>
48 {
49 // when stopped, the CD is loaded
50 template <class Event,class FSM>
on_entry__anon30fd97320111::my_machine_::State351 void on_entry(Event const& ,FSM&) {std::cout << "entering: State3" << std::endl;}
52 template <class Event,class FSM>
on_exit__anon30fd97320111::my_machine_::State353 void on_exit(Event const&,FSM& ) {std::cout << "leaving: State3" << std::endl;}
54 };
55
56 struct State4 : public msm::front::state<>
57 {
58 template <class Event,class FSM>
on_entry__anon30fd97320111::my_machine_::State459 void on_entry(Event const&,FSM& ) {std::cout << "entering: State4" << std::endl;}
60 template <class Event,class FSM>
on_exit__anon30fd97320111::my_machine_::State461 void on_exit(Event const&,FSM& ) {std::cout << "leaving: State4" << std::endl;}
62 };
63
64 // the initial state of the player SM. Must be defined
65 typedef State1 initial_state;
66
67 // transition actions
State2ToState3__anon30fd97320111::my_machine_68 void State2ToState3(none const&) { std::cout << "my_machine::State2ToState3\n"; }
State3ToState4__anon30fd97320111::my_machine_69 void State3ToState4(none const&) { std::cout << "my_machine::State3ToState4\n"; }
70 // guard conditions
always_true__anon30fd97320111::my_machine_71 bool always_true(none const& evt)
72 {
73 std::cout << "always_true" << std::endl;
74 return true;
75 }
always_false__anon30fd97320111::my_machine_76 bool always_false(none const& evt)
77 {
78 std::cout << "always_false" << std::endl;
79 return false;
80 }
81
82 typedef my_machine_ p; // makes transition table cleaner
83
84 // Transition table for player
85 struct transition_table : mpl::vector<
86 // Start Event Next Action Guard
87 // +---------+-------------+---------+---------------------+----------------------+
88 _row < State1 , none , State2 >,
89 a_row < State2 , none , State3 , &p::State2ToState3 >,
90 // +---------+-------------+---------+---------------------+----------------------+
91 row < State3 , none , State4 , &p::State3ToState4 , &p::always_true >,
92 g_row < State3 , none , State4 , &p::always_false >,
93 _row < State4 , event1 , State1 >
94 // +---------+-------------+---------+---------------------+----------------------+
95 > {};
96 // Replaces the default no-transition response.
97 template <class FSM,class Event>
no_transition__anon30fd97320111::my_machine_98 void no_transition(Event const& e, FSM&,int state)
99 {
100 std::cout << "no transition from state " << state
101 << " on event " << typeid(e).name() << std::endl;
102 }
103 };
104 // Pick a back-end
105 typedef msm::back::state_machine<my_machine_> my_machine;
106
107 //
108 // Testing utilities.
109 //
110 static char const* const state_names[] = { "State1", "State2", "State3", "State4" };
pstate(my_machine const & p)111 void pstate(my_machine const& p)
112 {
113 std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
114 }
115
test()116 void test()
117 {
118 my_machine p;
119
120 // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
121 // in this case it will also immediately trigger all anonymous transitions
122 p.start();
123 // this event will bring us back to the initial state and thus, a new "loop" will be started
124 p.process_event(event1());
125
126 }
127 }
128
main()129 int main()
130 {
131 test();
132 return 0;
133 }
134