table t : {A : int} fun main () : transaction page = let fun check () = r <- oneRow (SELECT SUM(t.A) AS X FROM t); return (if r.X < 0 then (Some 3, None) else (None, Some "Hi")) fun show (t ::: Type) (_ : show t) (opt : option t) = case opt of None => None | Some v => {[v]} in s <- source (None, None); return