src/Pure/System/session.scala

   val global_settings = new Event_Bus[Session.Global_Settings.type]
   val perspective = new Event_Bus[Session.Perspective.type]
   val assignments = new Event_Bus[Session.Assignment.type]
   val commands_changed = new Event_Bus[Session.Commands_Changed]
   val phase_changed = new Event_Bus[Session.Phase]
+  val syslog_messages = new Event_Bus[Isabelle_Process.Result]
+  val raw_output_messages = new Event_Bus[Isabelle_Process.Result]
   val raw_messages = new Event_Bus[Isabelle_Process.Message]  // potential bottle-neck
 
 
 
   /** buffered command changes (delay_first discipline) **/

             case input: Isabelle_Process.Input =>
               raw_messages.event(input)
 
             case result: Isabelle_Process.Result =>
               handle_result(result)
+              if (result.is_syslog) syslog_messages.event(result)
+              if (result.is_stdout) raw_output_messages.event(result)
               raw_messages.event(result)
           }
 
         case bad => System.err.println("session_actor: ignoring bad message " + bad)
       }