Re: [Haskell-cafe] Haskell function composition commutivity?

On Apr 13, 2021, at 2:02 PM, Tom Smeding wrote:

Although, because of the fact that you omitted 'Functor f =>' and instead chose to write the constraint in prose beforehand, I get the feeling that you may be speaking mathematically, not about Haskell as compiled by GHC.

Yes, mathematically, with Haskell-like syntax. Also the functors in question were intended to stand for specific functors, rather than be universally quantified. So perhaps better: Yoneda (with A some type and F some functor): foo :: forall b. (A -> b) -> F b <=> foo bar = fmap bar (foo (id @A) -- Viktor.