Question

I found answers explaining difference between newtype and data in Haskell. But if I have the following type synonym:

type Point = (Int,Int)

Would that be more efficient rather to use:

data Point = Pt (Int,Int) ?

Answer 1

Using type will be more efficient, as it incurs one less indirection than the data version.

Note that both are more inefficient than:

data Point = Point {-# UNPACK #-}!Int {-# UNPACK #-}!Int

as you can see from this earlier question on data representations.