Ur/Web: demo/subforms.ur annotate

Avoid redundant rollbacks

author	Adam Chlipala <adam@chlipala.net>
date	Sat, 02 Jun 2012 10:54:49 -0400
parents	0084af7af35a
children	be0c4e2e488a

rev	line source
adamc@780	1 fun sub r =
adamc@780	2 let
adamc@780	3 fun sub' ls =
adamc@780	4 case ls of
adamc@780	5 [] => <xml/>
adamc@780	6 \| r :: ls => <xml>
adamc@780	7 <li>{[r.Num]} = {[r.Text]}</li>
adamc@780	8 {sub' ls}
adamc@780	9 </xml>
adamc@780	10 in
adamc@780	11 return <xml><body>
adamc@780	12 {sub' r.Lines}
adamc@780	13 </body></xml>
adamc@780	14 end
adamc@780	15
adamc@780	16 fun subforms n =
adamc@780	17 if n <= 0 then
adamc@780	18 <xml/>
adamc@780	19 else
adamc@780	20 <xml>
adamc@780	21 <entry>
adamc@780	22 <hidden{#Num} value={show n}/>
adamc@780	23 <li>{[n]}: <textbox{#Text}/></li>
adamc@780	24 </entry>
adamc@780	25 {subforms (n - 1)}
adamc@780	26 </xml>
adamc@780	27
adamc@780	28 fun form n = return <xml><body>
adamc@780	29 <form>
adamc@780	30 <subforms{#Lines}>
adamc@780	31 {subforms n}
adamc@780	32 </subforms>
adamc@780	33 <submit action={sub}/>
adamc@780	34 </form>
adamc@780	35
adamc@780	36 <a link={form (n + 1)}>One more blank</a><br/>
adamc@780	37 {if n > 0 then
adamc@780	38 <xml><a link={form (n - 1)}>One fewer blank</a></xml>
adamc@780	39 else
adamc@780	40 <xml/>}
adamc@780	41 </body></xml>
adamc@780	42
adamc@780	43 fun main () = form 1

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