Ur/Web: demo/listEdit.ur annotate

annotate demo/listEdit.ur @ 1639:6c00d8af6239

Add a new scoping check for unification variables, to fix a type inference bug

author	Adam Chlipala <adam@chlipala.net>
date	Sun, 18 Dec 2011 11:29:13 -0500
parents	fb2a0e76dcef
children	e6bc6bbd7a32

rev	line source
adamc@646	1 datatype rlist = Nil \| Cons of {Data : source string,
adamc@646	2 NewData : source string,
adamc@646	3 Tail : source rlist}
adamc@646	4
adamc@646	5 fun showString ss =
adamc@646	6 s <- signal ss;
adamc@646	7 return <xml>{[s]}</xml>
adamc@646	8
adamc@646	9 fun show rls =
adamc@646	10 v <- signal rls;
adamc@646	11 show' v
adamc@646	12
adamc@646	13 and show' rl =
adamc@646	14 case rl of
adamc@646	15 Nil => return <xml/>
adamc@646	16 \| Cons {Data = ss, NewData = ss', Tail = rls} => return <xml>
adamc@646	17 <dyn signal={showString ss}/>
adamc@646	18 <button value="Change to:" onclick={s <- get ss'; set ss s}/>
adamc@646	19 <ctextbox source={ss'}/><br/>
adamc@646	20 <dyn signal={show rls}/>
adamc@646	21 </xml>
adamc@646	22
adamc@646	23 fun main () =
adamc@646	24 head <- source Nil;
adamc@646	25 tailP <- source head;
adamc@646	26 data <- source "";
adamc@646	27
adamc@646	28 let
adamc@646	29 fun add () =
adamc@646	30 data <- get data;
adamc@646	31 data <- source data;
adamc@646	32 ndata <- source "";
adamc@646	33 tail <- get tailP;
adamc@646	34 tail' <- source Nil;
adamc@646	35
adamc@646	36 let
adamc@646	37 val cons = Cons {Data = data, NewData = ndata, Tail = tail'}
adamc@646	38 in
adamc@646	39 set tail cons;
adamc@646	40 set tailP tail';
adamc@646	41
adamc@646	42 head' <- get head;
adamc@646	43 case head' of
adamc@646	44 Nil => set head cons
adamc@646	45 \| _ => return ()
adamc@646	46 end
adamc@646	47 in
adamc@646	48 return <xml><body>
adamc@646	49 <ctextbox source={data}/> <button value="Add" onclick={add ()}/><br/>
adamc@646	50 <br/>
adamc@646	51
adamc@646	52 <dyn signal={show head}/>
adamc@646	53 </body></xml>
adamc@646	54 end

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