change type of SEARCH message to take a DFA, instead of a searchString

shell/search-thread.sml

@@ -5,8 +5,9 @@ struct
   (* Prerequisite to sending message: move buffer to end. *)
   fun loop () =
     let
-      val (buffer, searchString, time) = Mailbox.recv SearchMailbox.mailbox
-      val searchList = SearchList.build (buffer, searchString)
+      val (buffer, dfa, time) = Mailbox.recv SearchMailbox.mailbox
+      val searchList =
+        raise Fail "todo: reimplement full builder for searchList"
       val msg = InputMsg.WITH_SEARCH_LIST (searchList, time)
       val () = InputMailbox.append msg
     in