[commit: packages/Cabal] ghc-head: Add Functor/Applicative instances for ParseResult (f2bf834)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/Cabal

On branch  : ghc-head
Link       : http://git.haskell.org/?p=packages/Cabal.git;a=commit;h=f2bf8347bedb396ddb05d3333f35ac7df493bb5d

>---------------------------------------------------------------

commit f2bf8347bedb396ddb05d3333f35ac7df493bb5d
Author: Benno Fünfstück <benno.fuenfstueck at gmail.com>
Date:   Wed Jul 10 19:23:29 2013 +0200

    Add Functor/Applicative instances for ParseResult
    
    ParseResult is a Monad, so it should also be a Functor and an Applicative.


>---------------------------------------------------------------

f2bf8347bedb396ddb05d3333f35ac7df493bb5d
 Cabal/Distribution/ParseUtils.hs |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Cabal/Distribution/ParseUtils.hs b/Cabal/Distribution/ParseUtils.hs
index 26f5666..3923d77 100644
--- a/Cabal/Distribution/ParseUtils.hs
+++ b/Cabal/Distribution/ParseUtils.hs
@@ -88,6 +88,7 @@ import Data.Maybe       (fromMaybe)
 import Data.Tree as Tree (Tree(..), flatten)
 import qualified Data.Map as Map
 import Control.Monad (foldM) 
+import Control.Applicative (Applicative(..))
 import System.FilePath (normalise)
 import Data.List (sortBy)
 
@@ -115,6 +116,14 @@ showPWarning fpath (UTFWarning line fname) =
 data ParseResult a = ParseFailed PError | ParseOk [PWarning] a
         deriving Show
 
+instance Functor ParseResult where
+        fmap f (ParseFailed err) = ParseFailed err
+        fmap f (ParseOk ws x) = ParseOk ws $ f x
+        
+instance Applicative ParseResult where
+        pure = ParseOk []
+        f <*> a = join $ fmap (\f' -> fmap f' a)
+
 instance Monad ParseResult where
         return = ParseOk []
         ParseFailed err >>= _ = ParseFailed err