You are zipping rather than taking the cross product.
Ben
On Fri, 27 Jan 2017, 22:09 sasa bogicevic,
What is wrong with my applicative instance for custom List type ?
data List a = Nil | Cons a (List a) deriving (Eq, Show)
instance Applicative List where pure x = Cons x Nil Nil <*> _ = Nil _ <*> Nil = Nil (Cons x xy) <*> (Cons z dy) = Cons (x z) (xy <*> dy)
Prelude> let functions = Cons (+1) (Cons (*2) Nil) Prelude> let values = Cons 1 (Cons 2 Nil) Prelude> functions <*> values Cons 2 (Cons 3 (Cons 2 (Cons 4 Nil))) -- I get Cons 2 (Cons 4 Nil) what is wrong with my Applicative instance ?
{ name: Bogicevic Sasa phone: +381606006200 }
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