In Haskell, why isn't there a TypeClass for things that can act like lists?

Question

I\'m reading Learn You a Haskell and I\'m wondering why so many things are acting like a list, and nothing in the Prelude is using the native facility of type classes to set

Answer 1

ByteString is not a generic type.

In other languages, there is something like Sequence for all list-like data structures. I think this works, with correct extensions:

class Seq a b | a -> b where
  head :: a -> b
  isTail :: a -> Bool

# ([a]) is a sequence of a's
instance Seq [a] a where
  head (x:xs) = x
  isTail = (== [])

# ByteString is a sequence of chars
instance Seq ByteString Char

Or try this?

type BS a = ByteString
instance List BS