shithub: MicroHs

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More instances

--- a/lib/Data/Either.hs

+++ b/lib/Data/Either.hs

@@ -3,6 +3,8 @@

 module Data.Either(module Data.Either) where

 import Prelude()              -- do not import Prelude

 import Primitives

+import Control.Applicative

+import Control.Monad

 import Data.Bool

 import Data.Eq

 import Data.Function

@@ -33,3 +35,13 @@

 instance forall a . Functor (Either a) where

   fmap _ (Left a) = Left a

   fmap f (Right b) = Right (f b)

+

+instance forall a . Applicative (Either a) where

+  pure b              = Right b

+  Right f <*> Right x = Right (f x)

+  Right _ <*> Left a  = Left a

+  Left a  <*> _       = Left a

+

+instance forall a . Monad (Either a) where

+  Right b >>= k = k b

+  Left a  >>= _ = Left a