[Haskell-beginners] what does (# a, s #) mean?

10 Apr 2011


      I came across this definition in ghc source

$GHC/compiler/utils/State.hs
=======================
newtype State s a = State { runState' :: s -> (# a, s #) }


What does the construct (# a, s #) mean?

Thanks & Regards,
Amitava Shee