[Haskell-cafe] Re: Monad instance for partially applied type constructor?

Alexander Solla ajs at 2piix.com
Thu Sep 30 00:28:27 EDT 2010

  On 09/29/2010 09:13 PM, Alexander Solla wrote:
>  On 09/29/2010 02:15 PM, DavidA wrote:
>>> instance Monad (\v ->  Vect k (Monomial v))
>>> > 
>> Yes, that is exactly what I am trying to say. And since I'm not 
>> allowed to say
>> it like that, I was trying to say it using a type synonym 
>> parameterised over v
>> instead.
> Why not:
> instance Monad ((->) Vect k (Monomial v))

Sorry, I guess this is a bit off.  I don't think you "really" want a 
monad.  I think you want something like the dual to the reader monad 
(i.e, a comonad)

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