Mercurial > urweb
view tests/dlist2.ur @ 1774:27fdd78bd2f5
Avoid redundant rollbacks
author | Adam Chlipala <adam@chlipala.net> |
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date | Sat, 02 Jun 2012 10:54:49 -0400 |
parents | 1a9171e31fd1 |
children |
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datatype dlist = Nil | Cons of string * source dlist fun delist dl = case dl of Nil => <xml>[]</xml> | Cons (x, s) => <xml>{[x]} <ctextbox/> :: {delistSource s}</xml> and delistSource s = <xml><dyn signal={dl <- signal s; return (delist dl)}/></xml> fun main () : transaction page = tail0 <- source Nil; tail <- source tail0; tb <- source ""; return <xml><body> {delist (Cons ("ROOT", tail0))} <br/> <ctextbox source={tb}/> <button value="Add" onclick={hd <- get tb; tl <- source Nil; old <- get tail; set old (Cons (hd, tl)); set tail tl}/> <button value="Reset" onclick={set tail0 Nil; set tail tail0}/> </body></xml>