Re: Is a a way to do a “Bare” state monad in modern Haskell?

Henning Thielemann lemming at henning-thielemann.de
Sat Feb 22 20:52:31 UTC 2020


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?


More information about the Libraries mailing list