1 files changed, 10 insertions, 1 deletions
diff --git a/util/set.lua b/util/set.lua
index 69dfef5d..dbff28b4 100644
--- a/util/set.lua
+++ b/util/set.lua
@@ -186,9 +186,18 @@ function set_mt.__tostring(set)
 	for item in pairs(items) do
 		s[#s+1] = tostring(item);
 	end
-	return t_concat(s, ", ");
+	return "{"..t_concat(s, ", ").."}";
 end
 
+function set_mt.__freeze(set)
+	local s = {};
+	for item in pairs(set._items) do
+		s[#s + 1] = item;
+	end
+	return s;
+end
+
+
 return {
 	new = new;
 	is_set = is_set;