lol took me forever to understand lwt but finally have concurrency in the actor event processing handlers

topinf.ml

@@ -44,7 +44,7 @@ let toplevel_value_bindings : Obj.t String.Map.t ref =
   ref String.Map.empty
 
 let ppf = ref Format.std_formatter
-let eval = ref None
+let eval = ref (fun _ _ -> ())
 
 let getvalue name =
   try String.Map.find name !toplevel_value_bindings
@@ -2398,5 +2398,5 @@ let init ppf =
   Location.input_phrase_buffer := Some phrase_buffer ;
   Sys.catch_break true ;
   run_hooks After_setup ;
-  eval := Some (eval_fun lb) ;
+  eval := eval_fun lb ;
   eval_fun lb