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

1 files changed, 115 insertions, 0 deletions

diff --git a/lib/tinyfsm/examples/elevator/elevator.cpp b/lib/tinyfsm/examples/elevator/elevator.cpp
new file mode 100644
index 00000000..6e792f64
--- /dev/null
+++ b/lib/tinyfsm/examples/elevator/elevator.cpp
@@ -0,0 +1,115 @@
+#include <tinyfsm.hpp>
+
+#include "elevator.hpp"
+#include "fsmlist.hpp"
+
+#include <iostream>
+
+class Idle; // forward declaration
+
+
+// ----------------------------------------------------------------------------
+// Transition functions
+//
+
+static void CallMaintenance() {
+  std::cout << "*** calling maintenance ***" << std::endl;
+}
+
+static void CallFirefighters() {
+  std::cout << "*** calling firefighters ***" << std::endl;
+}
+
+
+// ----------------------------------------------------------------------------
+// State: Panic
+//
+
+class Panic
+: public Elevator
+{
+  void entry() override {
+    send_event(MotorStop());
+  }
+};
+
+
+// ----------------------------------------------------------------------------
+// State: Moving
+//
+
+class Moving
+: public Elevator
+{
+  void react(FloorSensor const & e) override {
+    int floor_expected = current_floor + Motor::getDirection();
+    if(floor_expected != e.floor)
+    {
+      std::cout << "Floor sensor defect (expected " << floor_expected << ", got " << e.floor << ")" << std::endl;
+      transit<Panic>(CallMaintenance);
+    }
+    else
+    {
+      std::cout << "Reached floor " << e.floor << std::endl;
+      current_floor = e.floor;
+      if(e.floor == dest_floor)
+        transit<Idle>();
+    }
+  };
+};
+
+
+// ----------------------------------------------------------------------------
+// State: Idle
+//
+
+class Idle
+: public Elevator
+{
+  void entry() override {
+    send_event(MotorStop());
+  }
+
+  void react(Call const & e) override {
+    dest_floor = e.floor;
+
+    if(dest_floor == current_floor)
+      return;
+
+    /* lambda function used for transition action */
+    auto action = [] { 
+      if(dest_floor > current_floor)
+        send_event(MotorUp());
+      else if(dest_floor < current_floor)
+        send_event(MotorDown());
+    };
+
+    transit<Moving>(action);
+  };
+};
+
+
+// ----------------------------------------------------------------------------
+// Base state: default implementations
+//
+
+void Elevator::react(Call const &) {
+  std::cout << "Call event ignored" << std::endl;
+}
+
+void Elevator::react(FloorSensor const &) {
+  std::cout << "FloorSensor event ignored" << std::endl;
+}
+
+void Elevator::react(Alarm const &) {
+  transit<Panic>(CallFirefighters);
+}
+
+int Elevator::current_floor = Elevator::initial_floor;
+int Elevator::dest_floor    = Elevator::initial_floor;
+
+
+// ----------------------------------------------------------------------------
+// Initial state definition
+//
+FSM_INITIAL_STATE(Elevator, Idle)