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Solonarv/pointwise-vector.hs

Created December 24, 2018 16:21
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Pointwise Semigroup lifting via MonadZip
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pointwise-vector.hs
newtype Pointwise f a = Pointwise { getPointwise :: f a }
deriving newtype (Functor, Applicative, Alternative, Monad, MonadPlus, MonadZip)
deriving stock (Eq, Ord, Show, Read)
instance (MonadZip f, Semigroup a) => Semigroup (Pointwise f a) where
Pointwise xs <> Pointwise ys = Pointwise (mzipWith (<>) xs ys)
-- Now Maybe (Pointwise (Vector (Sum a))) is the monoid you're looking for
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