From 534fcc6ebeb60679be5875886df65af3c4c3545e Mon Sep 17 00:00:00 2001
From: John Wellbelove <john.wellbelove@asterconsulting.co.uk>
Date: Wed, 13 Aug 2025 10:46:14 +0100
Subject: [PATCH] Updated fsm generator

---
 include/etl/generators/fsm_generator.h | 79 ++++++++++++++++++--------
 1 file changed, 54 insertions(+), 25 deletions(-)

diff --git a/include/etl/generators/fsm_generator.h b/include/etl/generators/fsm_generator.h
index f3481e2f..161c413b 100644
--- a/include/etl/generators/fsm_generator.h
+++ b/include/etl/generators/fsm_generator.h
@@ -72,7 +72,9 @@ cog.outl("//********************************************************************
 #include "message_router.h"
 #include "integral_limits.h"
 #include "largest.h"
-#include "tuple.h"
+#if ETL_USING_CPP11
+  #include "tuple.h"
+#endif
 
 #include <stdint.h>
 
@@ -242,6 +244,7 @@ namespace etl
 
   class ifsm_state;
 
+#if ETL_USING_CPP11
   //***************************************************************************
   /// A class to store FSM states.
   //***************************************************************************
@@ -298,6 +301,7 @@ namespace etl
     /// Pointers to the states.
     etl::ifsm_state* states[sizeof...(TStates)]{ &etl::get<TStates>(storage)... };
   };
+#endif
 
   //***************************************************************************
   /// Interface class for FSM states.
@@ -536,30 +540,7 @@ namespace etl
       {
         etl::fsm_state_id_t next_state_id = p_state->process_event(message);
 
-        if (have_changed_state(next_state_id))
-        {
-          ETL_ASSERT_OR_RETURN_VALUE(next_state_id < number_of_states, ETL_ERROR(etl::fsm_state_id_exception), p_state->get_state_id());
-          etl::ifsm_state* p_next_state = state_list[next_state_id];
-
-          do
-          {
-            p_state->on_exit_state();
-            p_state = p_next_state;
-
-            next_state_id = p_state->on_enter_state();
-
-            if (have_changed_state(next_state_id))
-            {
-              ETL_ASSERT_OR_RETURN_VALUE(next_state_id < number_of_states, ETL_ERROR(etl::fsm_state_id_exception), p_state->get_state_id());
-              p_next_state = state_list[next_state_id];
-            }
-          } while (p_next_state != p_state); // Have we changed state again?
-        }
-        else if (is_self_transition(next_state_id))
-        {
-          p_state->on_exit_state();
-          p_state->on_enter_state();
-        }
+        process_state_change(next_state_id); 
       }
       else
       {
@@ -567,6 +548,21 @@ namespace etl
       }
     }
 
+    //*******************************************
+    /// Invoke a state transition.
+    //*******************************************
+    etl::fsm_state_id_t transition_to(etl::fsm_state_id_t new_state_id)
+    {
+      if (is_started())
+      {
+        return process_state_change(new_state_id);
+      }
+      else
+      {
+        return ifsm_state::No_State_Change;
+      }
+    }
+
     using imessage_router::accepts;
 
     //*******************************************
@@ -661,6 +657,39 @@ namespace etl
       return (next_state_id == ifsm_state::Self_Transition);
     }
 
+    //*******************************************
+    /// Core function to process a state change.
+    //*******************************************
+    virtual etl::fsm_state_id_t process_state_change(etl::fsm_state_id_t next_state_id)
+    {
+      if (have_changed_state(next_state_id))
+      {
+        ETL_ASSERT_OR_RETURN_VALUE(next_state_id < number_of_states, ETL_ERROR(etl::fsm_state_id_exception), p_state->get_state_id());
+        etl::ifsm_state* p_next_state = state_list[next_state_id];
+
+        do
+        {
+          p_state->on_exit_state();
+          p_state = p_next_state;
+
+          next_state_id = p_state->on_enter_state();
+
+          if (have_changed_state(next_state_id))
+          {
+            ETL_ASSERT_OR_RETURN_VALUE(next_state_id < number_of_states, ETL_ERROR(etl::fsm_state_id_exception), p_state->get_state_id());
+            p_next_state = state_list[next_state_id];
+          }
+        } while (p_next_state != p_state); // Have we changed state again?
+      }
+      else if (is_self_transition(next_state_id))
+      {
+        p_state->on_exit_state();
+        p_state->on_enter_state();
+      }
+
+      return p_state->get_state_id();
+    }
+
     etl::ifsm_state*    p_state;          ///< A pointer to the current state.
     etl::ifsm_state**   state_list;       ///< The list of added states.
     etl::fsm_state_id_t number_of_states; ///< The number of states.