[Haskell-cafe] Re: Applicative but not Monad

Tom Davie tom.davie at gmail.com
Sat Oct 31 07:25:17 EDT 2009

On 10/31/09, Heinrich Apfelmus <apfelmus at quantentunnel.de> wrote:
> The only possible monad instance would be
>    return x = Const mempty
>    fmap f (Const b) = Const b
>    join (Const b)   = Const b

Your join doesn't seem to have the right type... Unless I'm missing something.


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