In Hugs Graphics Library, many procedures call the function getEvent with a Window as the parameter. But getEvent is defined as below:

 

getEvent :: Events -> IO Event

 

How does this work? I've tryied to do something similar and got the following error message (in GHC):

 

    Couldn't match `Events' against `Window'
        Expected type: Events
        Inferred type: Window
    In the first argument of `getEvent', namely `w'
    In a do statement: e <- getEvent w

In time: my "Window" is defined as following

 

data Window = MkWindow {
    win     :: GLUT.Window,  -- the real window
    events  :: Events  -- the event stream
    }

 

And in Hugs Graphics Library the "Window" is defined as:

 

data Window = MkWindow {

    wnd     :: WND,          -- the real window
    events  :: Events,     -- the event stream
    graphic :: IORef (Draw ())  -- the current graphic
    }

Thanks,

Andre