From e6c5eae4a8057b76869195c6ba10e655df8e449e Mon Sep 17 00:00:00 2001
From: Helmut Merz <helmutm@cy55.de>
Date: Tue, 28 Jul 2026 19:46:21 +0200
Subject: [PATCH] message handlers: upon change of scope return new bhv, use
 this for next actor loop

---
 lib/core/actor.ex   | 5 +++--
 lib/core/core.ex    | 4 +++-
 lib/core/environ.ex | 4 +++-
 lib/core/program.ex | 3 ++-
 4 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/core/actor.ex b/lib/core/actor.ex
index 2262d95..24bffbf 100644
--- a/lib/core/actor.ex
+++ b/lib/core/actor.ex
@@ -8,8 +8,8 @@ defmodule Scopes.Core.Actor do
         Logger.debug([msg: inspect(msg)])
         case msg do
           {:message, msg} ->
-            bhv.(msg)
-            loop(bhv)
+            bhv_n = bhv.(msg)
+            loop(bhv_n || bhv)
           {:register, reg, name, value} -> 
             Registry.register(reg, name, value)
             loop(bhv)
@@ -39,6 +39,7 @@ defmodule Scopes.Core.Actor do
 
   def become(ac, bhv) do
     Kernel.send(ac, {:become, bhv})
+    bhv
   end
 
   def register(ac, reg, name, value \\ []) do
diff --git a/lib/core/core.ex b/lib/core/core.ex
index 1f1ad68..1fe0395 100644
--- a/lib/core/core.ex
+++ b/lib/core/core.ex
@@ -12,7 +12,9 @@ defmodule Scopes.Core do
   end
 
   def update(scope) do
-    Actor.become(self(), fn msg -> process(msg, scope) end)
+    bhv_n = fn msg -> process(msg, scope) end
+    Actor.become(self(), bhv_n)
+    bhv_n
   end
 
   def synapse(rcvr, op, delay \\ 0) do
diff --git a/lib/core/environ.ex b/lib/core/environ.ex
index d910d2d..101c700 100644
--- a/lib/core/environ.ex
+++ b/lib/core/environ.ex
@@ -37,6 +37,7 @@ defmodule Scopes.Core.Environ do
       [:csys, :created | _rest] -> process_created(msg, scope)
       _ -> send(Core.env(scope), msg) # forward message to application
     end
+    nil
   end
 
   def process_created(msg, {state, proc, syns, env}) do
@@ -49,11 +50,12 @@ defmodule Scopes.Core.Environ do
     end
     {step, seq} = List.pop_at(state.init_seq, 0)
     state1 = %State{init_seq: seq}
-    Core.update({state1, proc, syns, env})
+    n_bhv = Core.update({state1, proc, syns, env})
     if step do
       Process.sleep(1)
       step.()
     end
+    n_bhv
   end
 
   # accessing cell registry
diff --git a/lib/core/program.ex b/lib/core/program.ex
index e7a7a71..23df7a0 100644
--- a/lib/core/program.ex
+++ b/lib/core/program.ex
@@ -62,7 +62,7 @@ defmodule Scopes.Core.Program do
         [:csys, :connect | _rest] -> Core.connect(msg, scope)
         [:csys, :create | _rest] -> create(msg, scope)
         #[:csys, :next | _rest] -> next(msg, scope)
-        _ -> Core.forward(msg, scope) || Core.notify(msg, scope)
+        _ -> Core.forward(msg, scope) || Core.notify(msg, scope); nil
       end
     end
   end
@@ -98,6 +98,7 @@ defmodule Scopes.Core.Program do
       :pred -> Core.send_message(new, ~w(csys connect)a, Map.put(data, :target, self()))
       _ -> nil
     end
+    nil
   end
 
   # synapse operations