23 lines
503 B
Haskell
23 lines
503 B
Haskell
module Either (
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maybeToLeft
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, maybeToRight
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, leftToMaybe
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, rightToMaybe
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, maybeToEither
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) where
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leftToMaybe :: Either l r -> Maybe l
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leftToMaybe = either Just (const Nothing)
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rightToMaybe :: Either l r -> Maybe r
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rightToMaybe = either (const Nothing) Just
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maybeToRight :: l -> Maybe r -> Either l r
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maybeToRight l = maybe (Left l) Right
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maybeToLeft :: r -> Maybe l -> Either l r
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maybeToLeft r = maybe (Right r) Left
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maybeToEither :: Monoid b => Maybe a -> Either b a
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maybeToEither = maybe mempty
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