add ipairs and numeric indexing support to vector3

data/scripts/types/vector3.lua

@@ -169,8 +169,25 @@ function Vector3:__le(b)
   return self.x <= other.x and self.y <= other.y and self.z <= other.z
 end
 
-Vector3.__index = Vector3
+local NUMK = {"x", "y", "z"}
 
+function Vector3:__index(key)
+  -- this allows constructs like `for i, v in ipairs(Vector3(3, 2, 1))` to iterate over components
+  if type(key) == "number" then
+    return rawget(self, NUMK[key])
+  end
+
+  return rawget(Vector3, key)
+end
+
+function Vector3:__newindex(key, value)
+  if NUMK[key] then
+    rawset(self, NUMK[key], value)
+    return
+  end
+
+  rawset(self, key, value)
+end
 --------API--------
 
 function Vector3:length_squared()