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Diffstat (limited to 'libraries/base/Data/Either.hs')
| -rw-r--r-- | libraries/base/Data/Either.hs | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/libraries/base/Data/Either.hs b/libraries/base/Data/Either.hs index db340923e1..8bef30be9c 100644 --- a/libraries/base/Data/Either.hs +++ b/libraries/base/Data/Either.hs @@ -124,15 +124,18 @@ Left "parse error" data Either a b = Left a | Right b deriving (Eq, Ord, Read, Show) +-- | @since 3.0 instance Functor (Either a) where fmap _ (Left x) = Left x fmap f (Right y) = Right (f y) +-- | @since 3.0 instance Applicative (Either e) where pure = Right Left e <*> _ = Left e Right f <*> r = fmap f r +-- | @since 4.4.0.0 instance Monad (Either e) where Left l >>= _ = Left l Right r >>= k = k r |