From 4d39f5e52e1ca9e26a397eb4bcc2fe7bad18cdfe Mon Sep 17 00:00:00 2001
From: deva <deva>
Date: Mon, 9 Jun 2008 07:05:06 +0000
Subject: Corrected the mapper to do proper error checking.

---
 server/xml/macros/example.xml | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/server/xml/macros/example.xml b/server/xml/macros/example.xml
index 635dea2..f875747 100644
--- a/server/xml/macros/example.xml
+++ b/server/xml/macros/example.xml
@@ -9,8 +9,23 @@
       return math.pi, 1234567890
     </map>
     <map name="cyl">
-      -- LUA program
-      return lensmeter.right.cyl.value, lensmeter.right.cyl.timestamp
+      -- Returning 0, 0 invalidates the result
+      value = 0
+      timestamp = 0
+
+      -- Check for the existence of each level.
+      if( lensmeter and
+          lensmeter.right and
+          lensmeter.right.cyl and
+          lensmeter.right.cyl.value and 
+          lensmeter.right.cyl.timestamp )
+        then
+          timestamp = lensmeter.right.cyl.value
+          value = lensmeter.right.cyl.value end
+        end
+      end
+      
+      return value, timestamp
     </map>
   </maps>
   <luaprograms>
-- 
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