<div dir="ltr"><br><br><div class="gmail_quote">On Mon, Dec 21, 2009 at 4:10 AM, Antoine Latter <span dir="ltr"><<a href="mailto:aslatter@gmail.com">aslatter@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Folks,<br>
<br>
Would there be support for splitting off the MonadIO class from the<br>
mtl, and simple having Control.Monad.Trans re-export it?<br>
My proposed packaging of the functionality is here:<br>
<a href="http://community.haskell.org/%7Easlatter/code/monad-io" target="_blank">http://community.haskell.org/~aslatter/code/monad-io</a><br>
<br>
<br>
Here's my problem which prompted this:<br>
<br>
I'm converting a library of mine over to the failure[1] package for<br>
returning errors, and the type on a lot of my functions is as follows:<br>
<br>
(MonadFailure MyFailureType m, MonadIO m) => Alpha -> Beta -> m Gamma<br>
<br>
The MonadFailure constraint is defined separate from its many<br>
instances, which would give the consumers of my library the choice<br>
between using the mtl or the transformers[2] library.<br>
<br>
Except that I also need a MonadIO constraint, for which I must pick<br>
from which package I choose it.<br>
<br>
Antoine<br>
<br>
[1] <a href="http://hackage.haskell.org/package/failure" target="_blank">http://hackage.haskell.org/package/failure</a><br>
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</blockquote></div><br>+1, this is a great idea. I've had to purposely remove useful functions from safe-failure package due to this issue as well. I think we all agree that the best choice is to merge mtl and transformers, but since that discussion seems to have come to a stand-still, splitting off MonadIO and MonadTrans seems like a good second best.<br>
<br>Of course, I won't complain if someone just fixes the mtl/transformers mess itself ;).<br><br>Michael<br></div>