Cont as Monoid
Stefan O'Rear
stefanor at cox.net
Sat Sep 8 20:43:33 EDT 2007
On Sat, Sep 08, 2007 at 05:26:09PM -0700, Conal Elliott wrote:
> I'd like to see the following addition to Control.Monad.Cont in mtl:
>
> instance Monoid r => Monoid (Cont r a) where
> mempty = Cont mempty
> m `mappend` m' = Cont (runCont m `mappend` runCont m')
>
> What's the process for suggesting, discussing, and making such changes?
http://haskell.org/haskellwiki/Library_submissions
(My 2 cents: Why not mempty = return mempty; mappend = liftM2 mappend ?
Instances are best if unambiguous.)
(Why is there no liftM0 ?)
Stefan
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