Add tinyfsm, start converting core functions to an FSM-based event loop

lib/tinyfsm/examples/api/resetting_switch.cpp

@@ -0,0 +1,110 @@
+#include <tinyfsm.hpp>
+#include <iostream>
+
+class Off; // forward declaration
+
+
+// ----------------------------------------------------------------------------
+// 1. Event Declarations
+//
+struct Toggle : tinyfsm::Event { };
+
+
+// ----------------------------------------------------------------------------
+// 2. State Machine Base Class Declaration
+//
+class Switch
+: public tinyfsm::Fsm<Switch>
+{
+  // entry(), exit() and react() are called from Fsm<Switch>::transit()
+  // in derived states, make friends:
+  friend class tinyfsm::Fsm<Switch>;
+
+  /* default reaction for unhandled events */
+  void react(tinyfsm::Event const &) { };
+
+  virtual void react(Toggle const &) { };
+  virtual void entry(void) { };  /* entry actions in some states */
+  void         exit(void)  { };  /* no exit actions */
+
+public:
+  static void reset(void);   /* implemented below */
+};
+
+
+// ----------------------------------------------------------------------------
+// 3. State Declarations
+//
+class On
+: public Switch
+{
+  void entry() override { counter++; std::cout << "* Switch is ON, counter=" << counter << std::endl; };
+  void react(Toggle const &) override { transit<Off>(); };
+  int counter;
+
+public:
+  On() : counter(0) { std::cout << "** RESET State=On" << std::endl; }
+};
+
+class Off
+: public Switch
+{
+  void entry() override { counter++; std::cout << "* Switch is OFF, counter=" << counter << std::endl; };
+  void react(Toggle const &) override { transit<On>(); };
+  int counter;
+
+public:
+  Off() : counter(0) { std::cout << "** RESET State=Off" << std::endl; }
+};
+
+
+void Switch::reset() {
+  std::cout << "** RESET Switch" << std::endl;
+  // Reset all states (calls constructor on all states in list)
+  tinyfsm::StateList<Off, On>::reset();
+
+  // Alternatively, make counter public above and reset the values
+  // here instead of using a copy-constructor with StateList<>:
+  //state<On>().counter = 0;
+  //state<Off>().counter = 0;
+}
+
+FSM_INITIAL_STATE(Switch, Off)
+
+
+// ----------------------------------------------------------------------------
+// 4. State Machine List Declaration (dispatches events to multiple FSM's)
+//
+// In this example, we only have a single state machine, no need to use FsmList<>:
+//using fsm_handle = tinyfsm::FsmList< Switch >;
+using fsm_handle = Switch;
+
+
+// ----------------------------------------------------------------------------
+// Main
+//
+int main()
+{
+  fsm_handle::start();
+
+  while(1)
+  {
+    char c;
+    std::cout << std::endl << "t=Toggle, r=Restart, q=Quit ? ";
+    std::cin >> c;
+    switch(c) {
+    case 't':
+      std::cout << "> Toggling switch..." << std::endl;
+      fsm_handle::dispatch(Toggle());
+      break;
+    case 'r':
+      fsm_handle::reset();
+      fsm_handle::start();
+      break;
+    case 'q':
+      return 0;
+    default:
+      std::cout << "> Invalid input" << std::endl;
+    };
+  }
+}