At one time, I thought I understood Monad. However, when I try to connect my understanding of code to the piece of theory, I found myself still not clear. So he
I'm learning Haskell and trying to do exercises from book Haskell Programming from first principles and I'm stack trying to write applicative for Pair type da
I am trying to define an instance: newtype Join a = Join { getJoin :: a -> Bool } deriving Generic instance Monoid (Join a) where f <> g = ???