What do you mean “isn't actually bound”? The function being defined using colon syntax doesn't close over self, since it's a parameter—but functions defined within that function will close over the self parameter, since it's a local from an enclosing scope:

    foo = { x = 3 }
    function foo:bar(baz)
        return function(thud)
            return thud + baz + self.x
        end
    end

    womble = foo:bar(4)
    womble(7) --> 14

Python I believe also closes over self as a variable, and Ruby has similar behavior for local procs, even though « self » is a special form in Ruby.

This is in distinct contrast to JavaScript, where the value of the special form « this » goes nuts inside closures because it's attached to the function:

    foo = { x: 3 };
    foo.bar = function(baz) {
        return function(thud) {
            return thud + baz + this.x;
        };
    };

    womble = foo.bar(4);
    womble(7) # --> NaN

So in what way are you placing Lua and JavaScript together, and Python and Ruby together?

[slightly rearranged for clarity]