NestedInstantiationsBasedOnPreviousRecords.hs

-- NestedInstantiationsBasedOnPreviousRecords.hs
-- Inspired by: http://langexplr.blogspot.com/2012/01/quick-look-at-haskell-records.html

data Vector2D = Vector2D {
 x :: Double,
 y :: Double
} deriving Show

data Animated = Animated {
 position :: Vector2D,
 movement :: Vector2D
} deriving Show

animated0 = Animated {
 position = Vector2D { x = 10, y = 5 },
 movement = Vector2D { x = 1, y = (-1) }
}

animated1 = animated0 {
 position = (position animated0) { x = (y . position $ animated0) }
}

main = print animated0 >> print animated1