diff options
| -rw-r--r-- | libraries/base/Data/Either.hs | 3 | ||||
| -rw-r--r-- | libraries/base/Prelude.hs | 2 |
2 files changed, 4 insertions, 1 deletions
diff --git a/libraries/base/Data/Either.hs b/libraries/base/Data/Either.hs index 406e7e7e3b..65b366123d 100644 --- a/libraries/base/Data/Either.hs +++ b/libraries/base/Data/Either.hs @@ -35,6 +35,9 @@ 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 diff --git a/libraries/base/Prelude.hs b/libraries/base/Prelude.hs index 08fe811d76..cccfcb574f 100644 --- a/libraries/base/Prelude.hs +++ b/libraries/base/Prelude.hs @@ -31,7 +31,6 @@ module Prelude ( Ordering(LT, EQ, GT), Char, String, - IO, -- *** Tuples fst, snd, curry, uncurry, @@ -119,6 +118,7 @@ module Prelude ( showChar, showString, readParen, showParen, -- * Basic Input and output + IO, -- ** Simple I\/O operations -- All I/O functions defined here are character oriented. The -- treatment of the newline character will vary on different systems. |