Proposal: Make Semigroup and Monoid instances for Data.Functor.Compose
Keith
keith.wygant at gmail.com
Thu Jul 25 16:02:53 UTC 2019
With the Monoid 'First' and 'Last' newtypes going away, it would be nice to have equivalent Functor and Applicative instances.
This works if Compose uses its components' instances:
instance Semigroup (m (n a)) ⇒ Semigroup (Compose m n a) where
Compose mnx <> Compose mny = Compose (mnx <> mny)
instance Monoid (m (n a)) ⇒ Monoid (Compose m n a) where
mempty = Compose mempty
–Keith
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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