--- a/util/set.lua	Mon Sep 02 15:22:41 2013 +0100
+++ b/util/set.lua	Tue Sep 03 00:20:28 2013 +0100
@@ -91,13 +91,13 @@
 	end
 
 	function set:include(otherset)
-		for item in pairs(otherset) do
+		for item in otherset do
 			items[item] = true;
 		end
 	end
 
 	function set:exclude(otherset)
-		for item in pairs(otherset) do
+		for item in otherset do
 			items[item] = nil;
 		end
 	end