[Haskell-cafe] Either instance of Monad?

Yves Parès limestrael at gmail.com
Sat Feb 26 12:54:02 CET 2011


When I look at the documentation of Control.Monad.Error [1] or
Control.Applicative [2] it is not said that it re-exports
Control.Monad.Instances. So maybe this behaviour is normal...

[1]
http://hackage.haskell.org/packages/archive/mtl/2.0.1.0/doc/html/Control-Monad-Error.html
[2]
http://hackage.haskell.org/packages/archive/base/4.3.0.0/doc/html/Control-Applicative.html


2011/2/24 Yves Parès <limestrael at gmail.com>

> I have the same problem with instances of Functor.
> For instance when I import Control.Applicative, to get the instance
> "Functor ((->) a)" I also have to import Control.Monad.Instances.
>
>
> 2011/2/23 Daniel Fischer <daniel.is.fischer at googlemail.com>:
> > On Wednesday 23 February 2011 14:14:46, Yves Parès wrote:
> >> The latest, I think :
> >> GHC 7.0.1,
> >> mtl-2.0.1.0,
> >> base-4.3.0.0
> >
> > Hmm, that's exactly what I have. Weirder and weirder.
> > For the moment, I'm out of ideas.
> >
>
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