Proposal: Add a wrapped applicative type to Data.Monoid

[Daniel Cartwright]

I can definitely see "App" as being overloaded (Application).
Good names that I see are "Ap" and "Apply".

I think "Ap" is fine.
On Tue, Mar 27, 2018, 10:28 AM David Feuer <david.feuer at gmail.com> wrote:

> I proposed same thing some time ago. The main point of contention was the
> name. I hope you have better luck!
>
> On Tue, Mar 27, 2018, 10:23 AM Daniel Cartwright <chessai1996 at gmail.com>
> wrote:
>
>> I see this as being generally (as in, to the users of Haskell as a whole)
>> useful:
>>
>> newtype Ap f a = Ap { getAp :: f a }
>>   deriving (Applicative, Eq, Foldable, Functor, Generic, Generic1
>>                 ,Monad, Ord, Read, Show, Traversable)
>>
>> Some hand-written instances:
>> instance (Applicative f, Semigroup a) => Semigroup (Ap f a) where
>>   (Ap x) <> (Ap y) = Ap $ liftA2 (<>) x y
>>
>> instance (Applicative f, Monoid a) => Monoid (Ap f a) where
>>   mempty = Ap $ pure mempty
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>
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