[Haskell-cafe] A catch-all MonadIO instance

Ertugrul Soeylemez es at ertes.de
Fri Oct 28 16:59:55 CEST 2011

Bas van Dijk <v.dijk.bas at gmail.com> wrote:

> I understand, portability is important for transformers. For
> monad-control it's less of an issue because I already use other
> language extensions (incl. RankNTypes).
> So I think I go ahead and add a catch-all instance for MonadControlIO
> to monad-control.

I'm not sure whether this will work well.  You will get overlapping
instances, and I don't see a way to hide instances when importing.
Perhaps the OverlappingInstances extension could help here.


nightmare = unsafePerformIO (getWrongWife >>= sex)

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