Could iteratee depend on mtl instead of transformers?

Valery V. Vorotyntsev valery.vv at
Tue Nov 17 09:42:58 EST 2009

> Valery V. Vorotyntsev wrote:
>> 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)?

Henning Thielemann wrote:

> With 'ghc-pkg hide' and 'expose' you can set your general preference. With
> '-hide-package mtl' and '-package transformers' you can choose per
> invokation of GHCi.

``When you say import A.B.C, from what package does A.B.C come?''

I've found [*] a hackage wiki page devoted to this question:

  [*] I just tried to add `-hide-package mtl' to OPTIONS_GHC pragma,
      with no success, and was googling for a clue.

    Prelude> :load "/home/vvv/job/cdr.mscp/Codec/Binary/MSCP.hs"
        unknown flag in  {-# OPTIONS #-} pragma: -hide-package
        unknown flag in  {-# OPTIONS #-} pragma: mtl


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