[Haskell-cafe] StateT and ContT

[Dan Burton]

Do people actually *use* the MonadCont class? And those who do... do they
really use it in a way that would manifest this breakage?

basically every existing user of the instance is pretty much guaranteed to
> have breakage.


It seems the answer to these questions is "yes" and "yes." I'm curious to
hear more.

-- Dan Burton

On Tue, Jan 20, 2015 at 10:02 AM, Ross Paterson <R.Paterson at city.ac.uk>
wrote:

> On Wed, Jan 21, 2015 at 12:09:13AM +1100, Ivan Lazar Miljenovic wrote:
> > This is what I thought: I just wanted to make sure that I wasn't
> > missing something (especially since there's no real documentation that
> > I could find as to _how_ liftCallCC' fails to satisfy the laws of a
> > monad transformer).
>
> Any lifting of callCC should satisfy
>
>         lift (f k) = f' (lift . k) => lift (callCC f) = liftCallCC callCC
> f'
>
> and liftCallCC' doesn't.
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20150120/25bf4527/attachment.html>