(Viktor: sorry for the duplicate...) Does it make a difference? To me the following function type signatures mean exactly the same thing: foo :: (a -> b) -> f b foo :: forall a. (a -> b) -> f b foo :: forall b. (a -> b) -> f b foo :: forall a b. (a -> b) -> f b This of course changes when the `forall` is put inside the parentheses (though I don't think you meant that -- but I'm not a category theorist), or if ScopedTypeVariables is used nontrivially, or... etc. 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. - Tom On 13/04/2021 19:29, Viktor Dukhovni wrote:
On Tue, Apr 13, 2021 at 01:06:41PM -0400, Viktor Dukhovni wrote:
- Yoneda Lemma: Given a functor f and some function `foo` with signature:
foo :: forall a. (a -> b) -> f b
Sorry, typo, should be:
foo :: forall b. (a -> b) -> f b
-- Viktor. _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.