Could iteratee depend on mtl instead of transformers?

Valery V. Vorotyntsev valery.vv at
Tue Nov 17 06:22:48 EST 2009

Henning Thielemann wrote:

> The question is, whether Iteratee needs functions of MTL that
> transformers does not provide? 'Transformers' is the more basic
> package, entirely Haskell 98, thus should be prefered. It is however
> sad, that Transformers cannot easily be used with GHCi in parallel
> with MTL installed. I was always against that ... Renaming
> Control.Monad.Trans and Control.Monad.Identity to something else
> would solve the conflict. I'm also not happy, that you have to
> choose between monads-fd and monads-tf. I think it would be better
> to be able to have both type class approaches.

Is there a way to tell GHCi ``Take Control.Monad.Trans from mtl
package for this session'' or ``Use transformers this time'' without
updating ghc-pkg config file (hide/expose)?

If there is none, do you think inventing one would be a good idea?


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