get confused for functor of IO

[lemondreamtobe]

Document Delivery
`
// io_window_ :: IO Window
var io_window = new IO(function(){ return window; });

io_window.map(function(win){ return win.innerWidth });
// IO(1430)
`
i think the right Notes is IO(() => 1430). easy to understand
because compose return a function not a value.