X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Data%2FEither.hs;h=0c5e15347883878eca0ee28534ecd727d1ef24b5;hb=b9b6e38a1ebb5f05b382609fe0776d91cdd1090b;hp=406e7e7e3bb162dbf8be697f4b8bad69ef3391fa;hpb=2b09d1369ead1a675a916a3c928e0b72c169c3fe;p=haskell-directory.git diff --git a/Data/Either.hs b/Data/Either.hs index 406e7e7..0c5e153 100644 --- a/Data/Either.hs +++ b/Data/Either.hs @@ -1,4 +1,4 @@ -{-# OPTIONS -fno-implicit-prelude #-} +{-# OPTIONS_GHC -fno-implicit-prelude #-} ----------------------------------------------------------------------------- -- | -- Module : Data.Either @@ -20,9 +20,7 @@ module Data.Either ( #ifdef __GLASGOW_HASKELL__ import GHC.Base -#endif -#ifndef __HUGS__ {-| The 'Either' type represents values with two possibilities: a value of @@ -35,7 +33,10 @@ hold a correct value (mnemonic: \"right\" also means \"correct\"). -} data Either a b = Left a | Right b deriving (Eq, Ord ) +-- | Case analysis for the 'Either' type. +-- If the value is @'Left' a@, apply the first function to @a@; +-- if it is @'Right' b@, apply the second function to @b@. either :: (a -> c) -> (b -> c) -> Either a b -> c either f _ (Left x) = f x either _ g (Right y) = g y -#endif /* __HUGS__ */ +#endif /* __GLASGOW_HASKELL__ */