util.set: Add freeze metamethod

1 files changed, 8 insertions, 0 deletions

diff --git a/util/set.lua b/util/set.lua
index a4f20138..02fabc6a 100644
--- a/util/set.lua
+++ b/util/set.lua
@@ -23,6 +23,14 @@ function items_mt.__call(items, _, k)
 	return next(items, k);
 end
 
+function set_mt:__freeze()
+	local a, i = {}, 1;
+	for item in self._items do
+		a[i], i = item, i+1;
+	end
+	return a;
+end
+
 local function new(list)
 	local items = setmetatable({}, items_mt);
 	local set = { _items = items };