Add signal to handle state change

gui.py

@@ -335,6 +335,11 @@ def gui():
         encoder_backend.msc_callback = MSCHandler()
         encoder_backend.msc_callback.msc_box.connect(msc.addCondition)
         encoder_backend.tm_callback.got_tm.connect(editor.receivedTM)
+        # Callback in the backend to update the state of the SDL diagram
+        SDLHandler = type('SDLHandler', (QObject,), {'change_state':
+                                                      Signal(unicode)})
+        encoder_backend.sdl_callback = SDLHandler()
+        encoder_backend.sdl_callback.change_state.connect(sdl.change_state)
 
         encoder_backend.log = log
         encoder_backend.statusbar = statusbar

sdlHandler.py

@@ -69,3 +69,8 @@ class sdlHandler(object):
             self.dock.show()
         else:
             self.dock.hide()
+
+    @Slot(unicode)
+    def change_state(self, new_state):
+        ''' Highlight the current state on the statechart diagram '''
+        print 'changed state to ', new_state