done merging draw thread with update thread

shell/search-thread.sml

@@ -3,13 +3,13 @@ struct
   open CML
 
   (* Prerequisite to sending message: move buffer to end. *)
-  fun loop (searchMailbox, inputMailbox) =
+  fun loop () =
     let
-      val (buffer, searchString, time) = Mailbox.recv searchMailbox
+      val (buffer, searchString, time) = Mailbox.recv SearchMailbox.mailbox
       val searchList = SearchList.build (buffer, searchString)
       val msg = InputMsg.WITH_SEARCH_LIST (searchList, time)
-      val () = Mailbox.send (inputMailbox, msg)
+      val () = InputMailbox.append msg
     in
-      loop (searchMailbox, inputMailbox)
+      loop ()
     end
 end