--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/demo/buffer.ur	Sun Apr 05 10:48:11 2009 -0400
@@ -0,0 +1,25 @@
+datatype lines = End | Line of string * source lines
+
+type t = { Head : source lines, Tail : source (source lines) }
+
+val create =
+    head <- source End;
+    tail <- source head;
+    return {Head = head, Tail = tail}
+
+fun renderL lines =
+    case lines of
+        End => <xml/>
+      | Line (line, linesS) => <xml>{[line]}<br/><dyn signal={renderS linesS}/></xml>
+
+and renderS linesS =
+    lines <- signal linesS;
+    return (renderL lines)
+
+fun render t = renderS t.Head
+
+fun write t s =
+    oldTail <- get t.Tail;
+    newTail <- source End;
+    set oldTail (Line (s, newTail));
+    set t.Tail newTail