Simple Inheritance and overloading using typeclasses in haskell

simpleInheritance.hs

import Text.Printf (printf)

-----------------------------------------------------------------------------
{- interface: -}

data BaseObject = BaseObject { baseObjectA :: Int } -- the top-level object
class WithInheritedActions a where
  -- inherited actions:
  action1 :: a -> IO ()
  --action2 :: a -> Foo
  -- getters and setters for common fields:
  getA :: a -> Int
  setA :: a -> Int -> a

{- we make the top-level object an instance of subclass just to make
   the usage in subobjects easier. -}
instance WithInheritedActions BaseObject where
  action1 a = print "BaseObject"
  getA = baseObjectA
  setA a v = a { baseObjectA = v }

-----------------------------------------------------------------------------

{- usage examples: -}

data Object1 = Object1 { object1Base :: BaseObject } -- simple usage example.
instance WithInheritedActions Object1 where
  action1 a = printf "object1 with param=%d\n" $ getA a
  getA = getA . object1Base
  setA a v = a {object1Base = setA (object1Base a) v}

{- time to show some overloading: -}

data Object2 = Object2 { object2Base :: BaseObject }
instance WithInheritedActions Object2 where
  action1 a = print "object2"
  getA = getA . object2Base
  setA a v = a {object2Base = setA (object2Base a) v}


data Object3 = Object3 { object3Base :: Object2 }
instance WithInheritedActions Object3 where
  action1 a = do
    print "object 3, and... "
    action1 $ object3Base a
  getA = getA . object3Base
  setA a v = a {object3Base = setA (object3Base a) v}

-----------------------------------------------------------------------------

{- now the one can do: -}

main = do
  let
    o1 = Object1 $ BaseObject 12
    o2 = Object2 $ BaseObject 0
    o3 = Object3 $ o2
  action1 o1
  action1 $ setA o1 24
  action1 o2
  action1 o3