rxcpp-fsm is a library implementing a feature complete1 UML2 state machine in C++, using reactive extensions observables as events. Based on an idea by furuholm.
You need a C++ compiler that supports C++11. The library is developed and tested with gcc 7.4.0 and clang 8.
Complete UML2 feature set, including:
- All pseodostate types: Initial, Terminate, Entry point, Exit point, Choice, Join, Fork, Junction, Shallow History, Deep History
- Composite states
- Orthogonal states
- Sub-machine states
auto sm = rxcpp::fsm::make_state_machine("philosopher");
auto initial = rxcpp::fsm::make_initial_pseudostate("initial");
auto thinking = rxcpp::fsm::make_state("thinking");
auto hungry = rxcpp::fsm::make_state("hungry");
auto eating = rxcpp::fsm::make_state("eating");
auto eat_subject = rxcpp::subjects::subject<int>();
auto eat = eat_subject.get_observable();
initial.with_transition("initial", thinking);
thinking.with_on_entry([]() {
std::cout << "Thinking" << std::endl;
}).with_transition("thinking_to_hungry", hungry, std::chrono::milliseconds(500));
hungry.with_on_entry([]() {
std::cout << "Hungry" << std::endl;
}).with_transition("hungry_to_eating", eating, eat);
eating.with_on_entry([]() {
std::cout << "Eating" << std::endl;
}).with_transition("eating_to_thinking", thinking, std::chrono::milliseconds(500));
sm.with_state(initial, thinking, hungry, eating);
auto scheduler = rxcpp::schedulers::make_new_thread();
auto o = sm.assemble(rxcpp::serialize_one_worker(scheduler.create_worker()));
o.subscribe([](const rxcpp::fsm::transition& t) {
std::cout << "Taking transition " << t.name() << std::endl;
});1 Pseudostate Junction is currently implemented exactly as Choice which does not conform to the UML2 standard.