Add a set of default enabled language extensions.

The extensions in this list in the cabal file will be enabled for all
source files, so I've only made it the ones that are both widely used
and don't do anything weird or potentially unsafe or very slow.  Others
can be added as needed.

This also means the LANGUAGE pragmas for these extensions can be removed
from the source files.

Codec/RPM/Parse.hs

@@ -39,7 +39,7 @@ import Codec.RPM.Tags(Tag, mkTag)
 import Codec.RPM.Types(Header(..), Lead(..), RPM(..), SectionHeader(..))
 
 -- "a <$> b <$> c" looks better than "a . b <$> c"
-{-# ANN parseLead "HLint: ignore Functor law" #-}
+{-# ANN parseLead ("HLint: ignore Functor law" :: String) #-}
 parseLead :: Parser Lead
 parseLead = do
     -- Verify this is an RPM by checking the first four bytes.

Codec/RPM/Tags.hs

@@ -41,11 +41,11 @@ import           Text.PrettyPrint(text)
 
 import Codec.RPM.Internal.Numbers
 
-{-# ANN module "HLint: ignore Use camelCase" #-}
+{-# ANN module ("HLint: ignore Use camelCase" :: String) #-}
 
 -- The character lists are actually lists of characters, ignore the suggestions
 -- to use String instead
-{-# ANN module "HLint: ignore Use String" #-}
+{-# ANN module ("HLint: ignore Use String" :: String) #-}
 
 -- | A very large data type that holds all the possibilities for the various tags that can
 -- be contained in an 'Codec.RPM.Types.RPM' 'Codec.RPM.Types.Header'.  Each tag describes
@@ -772,7 +772,7 @@ mkI18NString store ty offset count | fromIntegral (BS.length store) - offset < c
 -- I don't know how to split a ByteString up into chunks of a given size, so here's what I'm doing.  Take
 -- a list of offsets of where in the ByteString to read.  Skip to each of those offsets, grab size bytes, and
 -- convert those bytes into the type using the given conversion function.  Return that list.
-{-# ANN readWords "HLint: ignore Eta reduce" #-}
+{-# ANN readWords ("HLint: ignore Eta reduce" :: String) #-}
 readWords :: BS.ByteString -> Int -> (BS.ByteString -> a) -> [Word32] -> [a]
 readWords bs size conv offsets = map (\offset -> conv $ BS.take size $ BS.drop (fromIntegral offset) bs) offsets
 

Codec/RPM/Types.hs

@@ -1,5 +1,3 @@
-{-# LANGUAGE RecordWildCards #-}
-
 -- |
 -- Module: Codec.RPM.Types
 -- Copyright: (c) 2016-2017 Red Hat, Inc.

Codec/RPM/Version.hs

@@ -1,6 +1,3 @@
-{-# LANGUAGE MultiWayIf #-}
-{-# LANGUAGE OverloadedStrings #-}
-
 -- |
 -- Module: Codec.RPM.Parse
 -- Copyright: (c) 2017 Red Hat, Inc.

codec-rpm.cabal

@@ -53,6 +53,11 @@ library
 
     default-language:   Haskell2010
 
+    default-extensions: LambdaCase,
+                        MultiWayIf,
+                        OverloadedStrings,
+                        RecordWildCards
+
     ghc-options:        -Wall
                         -Wincomplete-uni-patterns
                         -Wincomplete-record-updates
@@ -90,6 +95,11 @@ test-suite tests
 
     default-language:   Haskell2010
 
+    default-extensions: LambdaCase,
+                        MultiWayIf,
+                        OverloadedStrings,
+                        RecordWildCards
+
     ghc-options:        -Wall
                         -Wincomplete-uni-patterns
                         -Wincomplete-record-updates

examples/rpm2json.hs

@@ -15,7 +15,6 @@
 
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 {-# LANGUAGE TemplateHaskell #-}
-{-# LANGUAGE OverloadedStrings #-}
 
 import           Conduit((.|), Conduit, Consumer, awaitForever, runConduit, stdinC, yield)
 import           Control.Monad(void)

examples/unrpm.hs

@@ -13,7 +13,6 @@
 -- You should have received a copy of the GNU Lesser General Public
 -- License along with this library; if not, see <http://www.gnu.org/licenses/>.
 
-{-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE RankNTypes #-}
 
 import           Conduit((.|), Conduit, MonadResource, Producer, awaitForever, runConduitRes, sinkFile, sourceLazy, sourceFile, yield)

tests/Codec/RPM/Tags_mkTagSpec.hs

@@ -6,7 +6,7 @@ import Codec.RPM.Tags(mkTag, Tag(..), Null(..))
 import qualified Data.ByteString as BS
 import qualified Data.ByteString.Char8 as BC
 
-{-# ANN module "HLint: ignore Reduce duplication" #-}
+{-# ANN module ("HLint: ignore Reduce duplication" :: String) #-}
 
 spec :: Spec
 spec = describe "Codec.RPM.Tags.mkTag" $ do

tests/Codec/RPM/VersionSpec.hs

@@ -1,5 +1,3 @@
-{-# LANGUAGE OverloadedStrings #-}
-
 module Codec.RPM.VersionSpec (spec) where
 
 import           Test.Hspec