+$ model [xs=(list @t) draft=@t error=(unit @t)]
+$ message
  %start
  %stop
++ main (program init update view subs)
++ init |= ts=(list @t) [ts "" ~]
++ update |= [msg=message state=model]
  ^- [model (list (cmd message))] [state ~]
++ view |= state=model ^- (element message) (text "view")
++ subs |= state=model
  ^- (list (sub message))
    (~)