[Haskell-cafe] How to understand the fmap here ?

The following code snippets is from xmonad: -- Given a window, find the screen it is located on, and compute -- the geometry of that window wrt. that screen. floatLocation :: Window -> X (ScreenId, W.RationalRect) --....... rr <- snd `fmap` floatLocation w Prelude> :i fmap class Functor f where fmap :: (a -> b) -> f a -> f b It seems it is different from the definition of fmap ? sincerely! 2009-05-05 z_axis