Mercurial > urweb
diff demo/more/dlist.ur @ 951:103ac1792c41
Make filter argument to render, not create
author | Adam Chlipala <adamc@hcoop.net> |
---|---|
date | Thu, 17 Sep 2009 14:27:00 -0400 |
parents | da3ec6014d2f |
children | 07569af40069 |
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--- a/demo/more/dlist.ur Thu Sep 17 13:44:08 2009 -0400 +++ b/demo/more/dlist.ur Thu Sep 17 14:27:00 2009 -0400 @@ -6,19 +6,18 @@ Empty | Nonempty of { Head : dlist'' t, Tail : source (source (dlist'' t)) } -con dlist t = {Filter: t -> signal bool, - Elements : source (dlist' t)} +con dlist t = source (dlist' t) type position = transaction unit fun headPos [t] (dl : dlist t) = - dl' <- get dl.Elements; + dl' <- get dl; case dl' of Nonempty { Head = Cons (_, tl), Tail = tl' } => cur <- get tl; - set dl.Elements (case cur of - Nil => Empty - | _ => Nonempty {Head = cur, Tail = tl'}) + set dl (case cur of + Nil => Empty + | _ => Nonempty {Head = cur, Tail = tl'}) | _ => return () fun tailPos [t] (cur : source (dlist'' t)) new tail = @@ -29,20 +28,17 @@ Nil => set tail cur | _ => return () -fun create [t] r = - s <- source Empty; - return {Filter = r.Filter, - Elements = s} +val create [t] = source Empty -fun clear [t] (s : dlist t) = set s.Elements Empty +fun clear [t] (s : dlist t) = set s Empty fun append [t] dl v = - dl' <- get dl.Elements; + dl' <- get dl; case dl' of Empty => tl <- source Nil; tl' <- source tl; - set dl.Elements (Nonempty {Head = Cons (v, tl), Tail = tl'}); + set dl (Nonempty {Head = Cons (v, tl), Tail = tl'}); return (headPos dl) | Nonempty {Tail = tl, ...} => @@ -52,8 +48,8 @@ set tl new; return (tailPos cur new tl) -fun render [ctx] [ctx ~ body] [t] f dl = <xml> - <dyn signal={dl' <- signal dl.Elements; +fun render [ctx] [ctx ~ body] [t] f {Filter = filter, ...} dl = <xml> + <dyn signal={dl' <- signal dl; return (case dl' of Empty => <xml/> | Nonempty {Head = hd, Tail = tlTop} => @@ -67,7 +63,7 @@ None => headPos dl | Some prev => tailPos prev tl tlTop in - <xml><dyn signal={b <- dl.Filter v; + <xml><dyn signal={b <- filter v; return (if b then f v pos else @@ -91,7 +87,7 @@ return (x :: tl) fun elements [t] (dl : dlist t) = - dl' <- signal dl.Elements; + dl' <- signal dl; case dl' of Empty => return [] | Nonempty {Head = hd, ...} => elements' hd @@ -107,7 +103,7 @@ foldl'' i' dl' fun foldl' (i : acc) (dl : dlist t) : signal acc = - dl <- signal dl.Elements; + dl <- signal dl; case dl of Empty => return i | Nonempty {Head = dl, ...} => foldl'' i dl