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