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Diffstat (limited to 'libraries/base/Data/Either.hs')
| -rw-r--r-- | libraries/base/Data/Either.hs | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/libraries/base/Data/Either.hs b/libraries/base/Data/Either.hs index cf45e79456..5b3b5e2e70 100644 --- a/libraries/base/Data/Either.hs +++ b/libraries/base/Data/Either.hs @@ -56,6 +56,11 @@ instance Functor (Either a) where fmap _ (Left x) = Left x fmap f (Right y) = Right (f y) +instance Applicative (Either e) where + pure = Right + Left e <*> _ = Left e + Right f <*> r = fmap f r + instance Monad (Either e) where return = Right Left l >>= _ = Left l |