turings-tarpit/fsmtest.cpp

#include <fmt/core.h>

using namespace fmt;

template<typename S, typename E>
class DeadSimpleFSM {
protected:
  S _state = S::START;

public:
  virtual void event(E event) = 0;

  void state(S next_state) {
    _state = next_state;
  }
};

#define T(S, F) case S: F(); break

enum MyState {
  START, RUNNING, END
};

enum MyEvent {
  STARTED, PUSH, QUIT
};

class MyFSM : DeadSimpleFSM<MyState, MyEvent> {
public:
  void event(MyEvent ev) override {
    switch(ev) {
      T(STARTED, start);
      T(PUSH, push);
      T(QUIT, stop);
    }
  }

  void start() {
    println("<<< START");
    state(RUNNING);
  }

  void push() {
    println("<<< RUN");
    state(RUNNING);
  }

  void quit() {
    println("<<< STOP");
    state(END);
  }
};

int main() {
  MyFSM fsm;

  fsm.event(STARTED);
  fsm.event(PUSH);
  fsm.event(PUSH);
  fsm.event(PUSH);
  fsm.event(QUIT);
}