Proposal: add Bounded instances for Maybe and Either

[Edward Kmett]

Clever. I'm surprised those instances weren't already there.

On Mon, May 7, 2018 at 11:19 PM, David Feuer <david.feuer at gmail.com> wrote:

> We can write
>
> instance Bounded a => Bounded (Maybe a) where
>   minBound = Nothing
>   maxBound = Just maxBound
>
> instance (Bounded a, Bounded b) => Bounded (Either a b) where
>   minBound = Left minBound
>   maxBound = Right maxBound
>
> While Bounded intentionally does not have an Ord superclass, I think it's
> worth mentioning that these are the instances that arise naturally from the
> Ord instances for the types in question.
>
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