Mercurial > urweb
view demo/noisy.ur @ 726:6fc633d990e7
onError
author | Adam Chlipala <adamc@hcoop.net> |
---|---|
date | Thu, 16 Apr 2009 12:36:01 -0400 |
parents | 1a317a707d71 |
children | 15ddd64a5113 |
line wrap: on
line source
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 <- lookup id; alert (case ao of None => "Nada" | Some a => a); check ls' fun main () = idAdd <- source ""; aAdd <- source ""; idDel <- source ""; return <xml><body> <button value="Check values of 1, 2, and 3" onclick={check (Cons (1, Cons (2, Cons (3, Nil))))}/><br/> <br/> <button value="Add" onclick={id <- get idAdd; a <- get aAdd; add (readError id) a}/> <ctextbox source={idAdd}/> <ctextbox source={aAdd}/><br/> <br/> <button value="Delete" onclick={id <- get idDel; del (readError id)}/> <ctextbox source={idDel}/> </body></xml>