adam@10: (** Reactive view of the current time *)
adam@10: 
adam@10: type t = { Source : source time,
adam@10:            Period : int }
adam@10: 
adam@10: fun create ms =
adam@10:     tm <- now;
adam@10:     t <- source tm;
adam@10:     return {Source = t, Period = ms}
adam@10: 
adam@10: fun start t =
adam@10:     let
adam@10:         fun loop () =
adam@10:             sleep t.Period;
adam@10:             tm <- now;
adam@10:             set t.Source tm;
adam@10:             loop ()
adam@10:     in
adam@10:         spawn (loop ())
adam@10:     end
adam@10: 
adam@10: fun signal t = Basis.signal t.Source