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Revert "Add a maybeThese function to simplify constructing These from Maybes."

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This reverts commit 0893da5b7fb31bde527d3580e6daa04db5f7df3c.
This commit is contained in:
Rob Rix 2016-04-14 09:50:52 -04:00
parent fcaa498033
commit 4fa1067611
1 changed files with 0 additions and 7 deletions
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src/Data/Bifunctor/These.hs
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@ -17,13 +17,6 @@ these _ _ f (These this that) = f this that
fromThese :: a -> b -> These a b -> (a, b)
fromThese a b = these (flip (,) b) ((,) a) (,)
-- | Given a pair of Maybes, produce a These containing Just their values, or Nothing if they haven’t any.
maybeThese :: Maybe a -> Maybe b -> Maybe (These a b)
maybeThese (Just a) (Just b) = Just (These a b)
maybeThese (Just a) _ = Just (This a)
maybeThese _ (Just b) = Just (That b)
maybeThese _ _ = Nothing
-- | Return Just the value in This, or the first value in These, if any.
maybeFst :: These a b -> Maybe a
maybeFst = these Just (const Nothing) ((Just .) . const)