2016-05-13 08:49:19 +00:00
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{- This file is part of Vervis.
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-
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2019-03-28 21:08:30 +00:00
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- Written in 2016, 2019 by fr33domlover <fr33domlover@riseup.net>.
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2016-05-13 08:49:19 +00:00
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-
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- ♡ Copying is an act of love. Please copy, reuse and share.
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-
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- The author(s) have dedicated all copyright and related and neighboring
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- rights to this software to the public domain worldwide. This software is
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- distributed without any warranty.
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-
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- You should have received a copy of the CC0 Public Domain Dedication along
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- with this software. If not, see
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- <http://creativecommons.org/publicdomain/zero/1.0/>.
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-}
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module Data.Either.Local
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( maybeRight
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, maybeLeft
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2019-03-28 21:08:30 +00:00
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, requireEither
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2016-05-13 08:49:19 +00:00
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)
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where
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import Prelude
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maybeRight :: Either a b -> Maybe b
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maybeRight (Left _) = Nothing
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maybeRight (Right b) = Just b
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maybeLeft :: Either a b -> Maybe a
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maybeLeft (Left a) = Just a
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maybeLeft (Right _) = Nothing
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2019-03-28 21:08:30 +00:00
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requireEither :: Maybe a -> Maybe b -> Either Bool (Either a b)
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requireEither Nothing Nothing = Left False
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requireEither (Just _) (Just _) = Left True
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requireEither (Just x) Nothing = Right $ Left x
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requireEither Nothing (Just y) = Right $ Right y
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