1 files changed, 4 insertions, 0 deletions
diff --git a/lib/custodian/parser.rb b/lib/custodian/parser.rb
index 7ed7a51..268dd3b 100755
--- a/lib/custodian/parser.rb
+++ b/lib/custodian/parser.rb
@@ -190,6 +190,10 @@ class MonitorConfig
 
     end
 
+    if ( is_macro?( name ) )
+      raise ArgumentError, "The macro #{name} is already defined"
+    end
+
     @MACROS[name] = val
   end