diff --git a/util.lua b/util.lua
index 3e6f603..af1ad9d 100644
--- a/util.lua
+++ b/util.lua
@@ -1,7 +1,7 @@
 module 'aux'
 
 do
-	local classes, interfaces, objects = {}, {}, setmetatable({}, {__mode='k'})
+	local classes, constructors, interfaces, objects = {}, {}, {}, setmetatable({}, {__mode='k'})
 	local private_mt = {__metatable=false}
 	function private_mt:__newindex(k, v)
 		classes[self][k] = v
@@ -10,21 +10,26 @@ do
 	function public_mt:__newindex(k, v)
 		classes[self][k] = v
 		interfaces[self][k] = function(self, ...)
-			return classes[self][k](objects[self][k], unpack(arg))
+			return classes[self][k](objects[self], unpack(arg))
 		end
 	end
-	local proxy_mt = {__metatable=false}
+	local proxy_mt = {__metatable=false, __newindex=nop}
 	function proxy_mt:__call()
-		local proxy = setmetatable({}, {__metatable=false, __index=interfaces[self]})
-		objects[proxy] = setmetatable({}, {__index=classes[self]})
-		return proxy
+		local object = setmetatable({}, {__metatable=false, __newindex=nop, __index=interfaces[self]})
+		classes[object] = classes[self]
+		objects[object] = setmetatable({}, {__index=classes[self]})
+		constructors[self](objects[object])
+		return object
 	end
 	function M.class()
 		local class, interface = {}, {}
 		local private, public, proxy = setmetatable({}, private_mt), setmetatable({}, public_mt), setmetatable({}, proxy_mt)
 		classes[private], classes[public], classes[proxy] = class, class, class
 		interfaces[public], interfaces[proxy] = interface, interface
-		return private, public, proxy
+		return private, public, function(constructor)
+			constructors[proxy] = constructor or nop
+			return proxy
+		end
 	end
 end