both: Like Maybe, but with a different Monoid instance.

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The Monoid instance for Maybe behaves like so:

instance Monoid a => Monoid (Maybe a) where
  mappend (Just x) (Just y) = Just $ x <> y
  mappend (Just x) Nothing  = Just x
  mappend Nothing  (Just y) = Just y
  mappend Nothing  Nothing  = Nothing

  mempty = Nothing

Both is a newtype wrapper around Maybe providing this instance:

instance Monoid a => Monoid (Both a) where
  mappend (Just x) (Just y) = Just $ x <> y
  mappend _ _ = Nothing

  mempty = Just mempty

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Versions [RSS] 0.1.0.0, 0.1.1.0, 0.1.1.1, 0.1.1.2
Dependencies base (>=4.7 && <5.0), semigroups (>=0.16), zero (>=0.1 && <0.2) [details]
License MIT
Author Michael Walker
Maintainer mike@barrucadu.co.uk
Category Data
Home page https://github.com/barrucadu/both
Bug tracker https://github.com/barrucadu/both/issues
Source repo head: git clone https://github.com/barrucadu/both.git
this: git clone https://github.com/barrucadu/both.git(tag 0.1.1.2)
Uploaded by barrucadu at 2021-08-15T12:20:12Z
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Reverse Dependencies 1 direct, 0 indirect [details]
Downloads 2755 total (14 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2021-08-15 [all 1 reports]