auto document variable in ui-document lua script

res/scripts/stdlib.lua

@@ -110,4 +110,27 @@ end
 color_mt = {}
 function color_mt.__tostring(self)
     return "rgba("..self[1]..", "..self[2]..", "..self[3]..", "..self[4]..")"
-end
+end
+
+-- class designed for simple UI-nodes access via properties syntax
+local Element = {}
+function Element.new(docname, name)
+    return setmetatable({docname=docname, name=name}, {
+        __index=function(self, k)
+            return gui.getattr(self.docname, self.name, k)
+        end,
+        __newindex=function(self, k, v)
+            gui.setattr(self.docname, self.name, k, v)
+        end
+    })
+end
+
+-- the engine automatically creates an instance for every ui document (layout)
+Document = {}
+function Document.new(docname)
+    return setmetatable({name=docname}, {
+        __index=function(self, k)
+            return Element.new(self.name, k)
+        end
+    })
+end