How do I model inheritance in Haskell?

Question

I am attempting to create a game engine that is composed of a few different types:

data Camera = Camera ...
data Light = SpotLight ... | DirectionalLight ...         


        

Answer 1

I would implement it similar to:

type Position = (Double, Double, Double)
type Velocity = (Double, Double, Double)

class PhysicalObject a where
    pos :: a -> Position
    velocity :: a -> Velocity

data Camera = Camera
    { camPos :: Position
    , camVel :: Velocity
    } deriving (Eq, Show)

instance PhysicalObject Camera where
    pos = camPos
    velocity = camVel

Then you can do similarly for each type you define that needs PhysicalObject.