Use int for transition event instead of string

Using a string for the event identifier is costly as it requires
a lot more space than an int.

Fsm.cpp

@@ -38,7 +38,7 @@ Fsm::~Fsm()
 }
 
 
-void Fsm::add_transition(State* state_from, State* state_to, String event,
+void Fsm::add_transition(State* state_from, State* state_to, int event,
                          void (*on_transition)())
 {
   if (state_from == NULL || state_to == NULL)
@@ -57,7 +57,7 @@ void Fsm::add_transition(State* state_from, State* state_to, String event,
 }
 
 
-void Fsm::trigger(String event)
+void Fsm::trigger(int event)
 {
   // Find the transition with the current state and given event.
   Transition transition;

Fsm.h

@@ -39,16 +39,16 @@ class Fsm
   Fsm(State* initial_state);
   ~Fsm();
 
-  void add_transition(State* state_from, State* state_to, String event,
+  void add_transition(State* state_from, State* state_to, int event,
                       void (*on_transition)());
-  void trigger(String event);
+  void trigger(int event);
 
 private:
   struct Transition
   {
     State* state_from;
     State* state_to;
-    String event;
+    int event;
     void (*on_transition)();
   };
 

README.md

@@ -20,6 +20,7 @@ feature branch.
 * Add library.properties
 * Add keywords.txt
 * Remove name attribute from state
+* Use int for transition event instead of string
 
 **1.0.0 - 24/12/2013**
 

examples/light_switch/light_switch.ino

@@ -1,5 +1,13 @@
 #include <Fsm.h>
 
+// State machine variables
+#define FLIP_LIGHT_SWITCH 1
+
+State state_light_on(on_light_on_enter, &on_light_on_exit);
+State state_light_off(on_light_off_enter, &on_light_off_exit);
+Fsm fsm(&state_light_off);
+
+// Transition callback functions
 void on_light_on_enter()
 {
   Serial.println("Entering LIGHT_ON");
@@ -30,24 +38,23 @@ void on_trans_light_off_light_on()
   Serial.println("Transitioning from LIGHT_OFF to LIGHT_ON");
 }
 
-State state_light_on(on_light_on_enter, &on_light_on_exit);
-State state_light_off(on_light_off_enter, &on_light_off_exit);
-Fsm fsm(&state_light_off);
-
+// standard arduino functions
 void setup()
 {
   Serial.begin(9600);
 
-  fsm.add_transition(&state_light_on, &state_light_off, "flip_switch",
+  fsm.add_transition(&state_light_on, &state_light_off,
+                     FLIP_LIGHT_SWITCH,
                      &on_trans_light_on_light_off);
-  fsm.add_transition(&state_light_off, &state_light_on, "flip_switch",
+  fsm.add_transition(&state_light_off, &state_light_on,
+                     FLIP_LIGHT_SWITCH,
                      &on_trans_light_off_light_on);
 }
 
 void loop()
 {
   delay(2000);
-  fsm.trigger("flip_switch");
+  fsm.trigger(FLIP_LIGHT_SWITCH);
   delay(2000);
-  fsm.trigger("flip_switch");
+  fsm.trigger(FLIP_LIGHT_SWITCH);
 }