X-Git-Url: https://git.enpas.org/?a=blobdiff_plain;f=util%2Fset.lua;h=5f7a9ae243cef7d92bc13c63e1d32aed62bb3cb0;hb=322fdb77fe58eafac7204955fb5b3146ee8700ea;hp=bb318adf5290a207d41c3c7f0a2144acf4dd2dcd;hpb=35d012211b0504a3076bf55e3d02988329d63203;p=prosody.git

diff --git a/util/set.lua b/util/set.lua
index bb318adf..5f7a9ae2 100644
--- a/util/set.lua
+++ b/util/set.lua
@@ -1,3 +1,11 @@
+-- Prosody IM
+-- Copyright (C) 2008-2009 Matthew Wild
+-- Copyright (C) 2008-2009 Waqas Hussain
+-- 
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
 local ipairs, pairs, setmetatable, next, tostring = 
       ipairs, pairs, setmetatable, next, tostring;
 local t_concat = table.concat;
@@ -141,4 +149,8 @@ function intersection(set1, set2)
 	return set;
 end
 
+function xor(set1, set2)
+	return union(set1, set2) - intersection(set1, set2);
+end
+
 return _M;