datatype list t = Nil | Cons of t * list t table t : { Id : int, A : string } PRIMARY KEY Id fun add id s = dml (INSERT INTO t (Id, A) VALUES ({[id]}, {[s]})) fun del id = dml (DELETE FROM t WHERE t.Id = {[id]}) fun lookup id = ro <- oneOrNoRows (SELECT t.A FROM t WHERE t.Id = {[id]}); case ro of None => return None | Some r => return (Some r.T.A) fun check ls = case ls of Nil => return () | Cons (id, ls') => ao <- rpc (lookup id); alert (case ao of None => "Nada" | Some a => a); check ls' fun main () = idAdd <- source ""; aAdd <- source ""; idDel <- source ""; return