Code cleanup: removed duplicated versions of readPToMaybe.

Cabal/Distribution/ParseUtils.hs

@@ -36,6 +36,7 @@ module Distribution.ParseUtils (
         field, simpleField, listField, listFieldWithSep, spaceListField,
         commaListField, commaListFieldWithSep, commaNewLineListField,
         optsField, liftField, boolField, parseQuoted, parseMaybeQuoted, indentWith,
+        readPToMaybe,
 
         UnrecFieldParser, warnUnrec, ignoreUnrec,
   ) where
@@ -697,3 +698,7 @@ parseMaybeQuoted p = parseQuoted p <++ p
 
 parseFreeText :: ReadP.ReadP s String
 parseFreeText = ReadP.munch (const True)
+
+readPToMaybe :: ReadP a a -> String -> Maybe a
+readPToMaybe p str = listToMaybe [ r | (r,s) <- readP_to_S p str
+                                     , all isSpace s ]

Cabal/Distribution/Simple/BuildTarget.hs

@@ -55,6 +55,7 @@ import Distribution.Verbosity
 
 import qualified Distribution.Compat.ReadP as Parse
 import Distribution.Compat.ReadP ( (+++), (<++) )
+import Distribution.ParseUtils ( readPToMaybe )
 
 import Control.Monad ( msum )
 import Data.List ( stripPrefix, groupBy, partition )
@@ -207,10 +208,6 @@ readUserBuildTarget targetstr =
     parseHaskellString :: Parse.ReadP r String
     parseHaskellString = Parse.readS_to_P reads
 
-    readPToMaybe :: Parse.ReadP a a -> String -> Maybe a
-    readPToMaybe p str = listToMaybe [ r | (r,s) <- Parse.readP_to_S p str
-                                         , all isSpace s ]
-
 data UserBuildTargetProblem
    = UserBuildTargetUnrecognised String
   deriving Show

Cabal/Distribution/Simple/Setup.hs

@@ -82,6 +82,7 @@ import Distribution.Compiler
 import Distribution.ReadE
 import Distribution.Text
 import qualified Distribution.Compat.ReadP as Parse
+import Distribution.ParseUtils (readPToMaybe)
 import qualified Text.PrettyPrint as Disp
 import Distribution.ModuleName
 import Distribution.Package
@@ -2187,10 +2188,6 @@ optionNumJobs get set =
 -- * Other Utils
 -- ------------------------------------------------------------
 
-readPToMaybe :: Parse.ReadP a a -> String -> Maybe a
-readPToMaybe p str = listToMaybe [ r | (r,s) <- Parse.readP_to_S p str
-                                     , all isSpace s ]
-
 -- | Arguments to pass to a @configure@ script, e.g. generated by
 -- @autoconf@.
 configureArgs :: Bool -> ConfigFlags -> [String]

cabal-install/Distribution/Client/BuildTarget.hs

@@ -74,7 +74,7 @@ import Data.Function
 import Data.List
          ( nubBy, stripPrefix, partition, intercalate, sortBy, groupBy )
 import Data.Maybe
-         ( listToMaybe, maybeToList )
+         ( maybeToList )
 import Data.Ord
          ( comparing )
 import GHC.Generics (Generic)
@@ -97,6 +97,8 @@ import Control.Applicative (Alternative(..))
 import qualified Distribution.Compat.ReadP as Parse
 import Distribution.Compat.ReadP
          ( (+++), (<++) )
+import Distribution.ParseUtils
+         ( readPToMaybe )
 import Data.Char
          ( isSpace, isAlphaNum )
 import System.FilePath as FilePath
@@ -399,10 +401,6 @@ parseUserBuildTarget targetstr =
     parseHaskellString :: Parse.ReadP r String
     parseHaskellString = Parse.readS_to_P reads
 
-    readPToMaybe :: Parse.ReadP a a -> String -> Maybe a
-    readPToMaybe p str = listToMaybe [ r | (r,s) <- Parse.readP_to_S p str
-                                         , all isSpace s ]
-
 -- | Syntax error when trying to parse a 'UserBuildTarget'.
 data UserBuildTargetProblem
    = UserBuildTargetUnrecognised String

cabal-install/Distribution/Client/Setup.hs

@@ -93,7 +93,7 @@ import Distribution.Simple.Setup
          , Flag(..), toFlag, flagToMaybe, flagToList
          , BooleanFlag(..), optionVerbosity
          , boolOpt, boolOpt', trueArg, falseArg
-         , readPToMaybe, optionNumJobs )
+         , optionNumJobs )
 import Distribution.Simple.InstallDirs
          ( PathTemplate, InstallDirs(dynlibdir, sysconfdir)
          , toPathTemplate, fromPathTemplate )
@@ -111,6 +111,8 @@ import Distribution.ReadE
          ( ReadE(..), readP_to_E, succeedReadE )
 import qualified Distribution.Compat.ReadP as Parse
          ( ReadP, char, munch1, pfail,  (+++) )
+import Distribution.ParseUtils
+         ( readPToMaybe )
 import Distribution.Verbosity
          ( Verbosity, lessVerbose, normal )
 import Distribution.Simple.Utils

cabal-install/Distribution/Client/Targets.hs

@@ -102,6 +102,8 @@ import Control.Monad (mapM)
 import qualified Distribution.Compat.ReadP as Parse
 import Distribution.Compat.ReadP
          ( (+++), (<++) )
+import Distribution.ParseUtils
+         ( readPToMaybe )
 import qualified Text.PrettyPrint as Disp
 import Text.PrettyPrint
          ( (<+>) )
@@ -301,10 +303,6 @@ readUserTarget targetstr =
           v | v == nullVersion -> Dependency (packageName p) anyVersion
             | otherwise        -> Dependency (packageName p) (thisVersion v)
 
-readPToMaybe :: Parse.ReadP a a -> String -> Maybe a
-readPToMaybe p str = listToMaybe [ r | (r,s) <- Parse.readP_to_S p str
-                                     , all isSpace s ]
-
 
 reportUserTargetProblems :: [UserTargetProblem] -> IO ()
 reportUserTargetProblems problems = do