Ur/Web: tests/rpcDE.ur annotate

Fix a read-after-free bug using a timestamp check

author	Adam Chlipala <adam@chlipala.net>
date	Thu, 19 Nov 2015 13:18:58 -0500
parents	3ee6bb48f6e8
children

rev	line source
adamc@638	1 datatype result = Neg \| Zero \| Pos
adamc@638	2
adamc@638	3 table t : {A : int}
adamc@638	4
adamc@638	5 fun main () : transaction page =
adamc@638	6 let
adamc@638	7 fun check () =
adamc@638	8 r <- oneRow (SELECT SUM(t.A) AS X FROM t);
adamc@638	9 return (if r.X < 0 then
adamc@638	10 Neg
adamc@638	11 else if r.X = 0 then
adamc@638	12 Zero
adamc@638	13 else
adamc@638	14 Pos)
adamc@638	15
adamc@638	16 fun show r =
adamc@638	17 case r of
adamc@638	18 Neg => <xml>-</xml>
adamc@638	19 \| Zero => <xml>0</xml>
adamc@638	20 \| Pos => <xml>+</xml>
adamc@638	21 in
adamc@638	22 s <- source Zero;
adamc@638	23 return <xml><body>
adamc@638	24 <button value="Get It On!"
adamc@638	25 onclick={r <- check ();
adamc@638	26 set s r}/><br/>
adamc@638	27 <br/>
adamc@638	28 Current: <dyn signal={r <- signal s; return (show r)}/>
adamc@638	29 </body></xml>
adamc@638	30 end

Mercurial > urweb