adam@1: datatype readiness a = Ready of a | Waiting | Invalid of string
adam@1: datatype rpcResult a = Success of a | Failure of string
adam@1: 
adam@1: fun warning [a] (s : signal (readiness a)) =
adam@1:     <xml><dyn signal={v <- s;
adam@1:                       return (case v of
adam@1:                                   Invalid s => <xml><b>{[s]}</b></xml>
adam@1:                                 | _ => <xml/>)}/></xml>
kkallio@9: 
kkallio@9: fun warningFmt [a ::: Type] [ctx ::: {Unit}] [ctx ~ body] 
kkallio@9:                (wrap : string -> xml (body ++ ctx) [] []) 
kkallio@9:                (s : signal (readiness a)) =
kkallio@9:     <xml><dyn signal={v <- s;
kkallio@9:                       return (case v of
kkallio@9:                                   Invalid s => wrap s
kkallio@9:                                 | _ => <xml/>)}/></xml>