Is a a way to do a “Bare” state monad in modern Haskell?
1) we have a monad instance for (r -> ) 2) is there some way we can arrange sans newtype an instance for its state monad sibling ( /\ x . s-> (s,x)) without a type lambda or some new type or injective type families? I can definitely see that this is def not possible with h98-h2010, is this otherwise expressible? Mostly just curious if there’s some trick that’s now possible :)
On Sat, 22 Feb 2020, Carter Schonwald wrote:
1) we have a monad instance for (r -> )
And a duplicate Writer monad for (,) w.
2) is there some way we can arrange sans newtype an instance for its state monad sibling ( /\ x . s-> (s,x)) without a type lambda or some new type or injective type families? I can definitely see that this is def not possible with h98-h2010, is this otherwise expressible?
Why should one want this?
participants (2)
-
Carter Schonwald -
Henning Thielemann