import SimplePrelude

-- The type of an array containing elements of type `a`:
type Array a = Int -> a

-- Constructors of arrays:

-- The empty array:
emptyArray :: Array a
emptyArray = \i -> error "Access to non-initialized index!"

-- An array with an init value:
initArray :: a -> Array a
--initArray iv = \i -> iv
initArray iv = const iv

-- Put an element at an index into an array:
putIndex :: Array a -> Int -> a -> Array a
putIndex a i v = a'
 where a' j | j == i    = v
            | otherwise = a j

-- Get an element at an index position in an array: selector a[i]
getIndex :: Array a -> Int -> a
getIndex a i = a i

zeroArray :: Array Int
zeroArray = initArray 0

oneTwoArray :: Array Int
oneTwoArray = putIndex (putIndex zeroArray 1 42) 2 99