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diff tests/rpcO.ur @ 641:b98f547a6a45

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RPC returning an option
author Adam Chlipala <adamc@hcoop.net>
date Sun, 08 Mar 2009 13:41:55 -0400
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/rpcO.ur	Sun Mar 08 13:41:55 2009 -0400
@@ -0,0 +1,25 @@
+table t : {A : int}
+
+fun main () : transaction page =
+    let
+        fun check () =
+            r <- oneRow (SELECT SUM(t.A) AS X FROM t);
+            return (if r.X < 0 then
+                        (Some 3, None)
+                    else
+                        (None, Some "Hi"))
+
+        fun show (t ::: Type) (_ : show t) (opt : option t) =
+            case opt of
+                None => <xml>None</xml>
+              | Some v => <xml>{[v]}</xml>
+    in
+        s <- source (None, None);
+        return <xml><body>
+          <button value="Get It On!"
+                  onclick={r <- check ();
+                           set s r}/><br/>
+          <br/>
+          Current: <dyn signal={p <- signal s; return <xml>{show p.1}, {show p.2}</xml>}/>
+        </body></xml>
+    end