__index and function args

["Wesley Smith" <wesley.hoke@...>]

Let's say I have

Obj = {}
Obj_mt = { __index = function(t, k) -- do something
                    end
        }

function Obj.new(o)
   setmetatable(o, Obj_mt)
   return o
end

obj1 = Obj.new{}
obj1:draw_circle(0, 0, 0.5)


When draw_circle is called, it looks up __index and falls the function
defined in the metatable above where t = obj1 and k = "draw_circle".

My question is, how do I get at the arguments?  What happens to 0, 0,
0.5 and how can I access them?

thanks,
wes