Add some new row instances and remove some dead code.

postgresql-simple.cabal

@@ -16,7 +16,7 @@ Cabal-version:       >= 1.9.2
 
 extra-source-files:
      CONTRIBUTORS
-     CHANGELOG.md
+     CHANGES.md
 
 Library
   hs-source-dirs: src

src/Database/PostgreSQL/Simple/Compat.hs

@@ -51,23 +51,9 @@ import Unsafe.Coerce (unsafeCoerce)
 -- 'withTransactionMode' function calls the restore callback only once, so we
 -- don't need that polymorphism.
 mask :: ((IO a -> IO a) -> IO b) -> IO b
-#if MIN_VERSION_base(4,3,0)
 mask io = E.mask $ \restore -> io restore
-#else
-mask io = do
-    b <- E.blocked
-    E.block $ io $ \m -> if b then m else E.unblock m
-#endif
 {-# INLINE mask #-}
 
-#if !MIN_VERSION_base(4,5,0)
-infixr 6 <>
-
-(<>) :: Monoid m => m -> m -> m
-(<>) = mappend
-{-# INLINE (<>) #-}
-#endif
-
 toByteString :: Builder -> ByteString
 #if MIN_VERSION_bytestring(0,10,0)
 toByteString x = toStrict (toLazyByteString x)

src/Database/PostgreSQL/Simple/FromRow.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RecordWildCards, FlexibleInstances, DefaultSignatures #-}
 
@@ -36,6 +37,11 @@ import           Control.Monad.Trans.Reader
 import           Control.Monad.Trans.Class
 import           Data.ByteString (ByteString)
 import qualified Data.ByteString.Char8 as B
+#if MIN_VERSION_base(4,9,0)
+import           Data.Functor.Const
+import           Data.Functor.Identity
+import qualified Data.List.NonEmpty as NE
+#endif
 import           Data.Vector (Vector)
 import qualified Data.Vector as V
 import           Database.PostgreSQL.Simple.Types (Only(..))
@@ -108,8 +114,8 @@ fieldWith fieldP = RP $ do
                 ""
                 ("at least " ++ show (unCol column + 1)
                   ++ " slots in target type")
-                "mismatch between number of columns to \
-                \convert and number in target type"
+                ("mismatch between number of columns to convert and number"
+                 ++ "in target type")
         conversionError err
     else do
       let !result = rowresult
@@ -141,6 +147,27 @@ instance (FromField a) => FromRow (Maybe (Only a)) where
     fromRow =  (null *> pure Nothing)
            <|> (Just <$> fromRow)
 
+#if MIN_VERSION_base(4,9,0)
+instance (FromField a) => FromRow (Identity a) where
+    fromRow = Identity <$> field
+
+instance (FromField a) => FromRow (Const a b) where
+    fromRow = Const <$> field
+
+instance (FromField a) => FromRow (Maybe (Identity a)) where
+    fromRow =  (null *> pure Nothing)
+           <|> (Just <$> fromRow)
+
+instance (FromField a) => FromRow (Maybe (Const a b)) where
+    fromRow =  (null *> pure Nothing)
+           <|> (Just <$> fromRow)
+
+instance (FromField a) => FromRow (NE.NonEmpty a) where
+    fromRow = do
+      n <- numFieldsRemaining
+      (NE.:|) <$> field <*> replicateM (n - 1) field
+#endif
+
 instance (FromField a, FromField b) => FromRow (a,b) where
     fromRow = (,) <$> field <*> field
 

src/Database/PostgreSQL/Simple/ToRow.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE DefaultSignatures, FlexibleInstances, FlexibleContexts #-}
+{-# LANGUAGE CPP, DefaultSignatures, FlexibleInstances, FlexibleContexts #-}
 ------------------------------------------------------------------------------
 -- |
 -- Module:      Database.PostgreSQL.Simple.ToRow
@@ -23,6 +23,14 @@ module Database.PostgreSQL.Simple.ToRow
 
 import Database.PostgreSQL.Simple.ToField (Action(..), ToField(..))
 import Database.PostgreSQL.Simple.Types (Only(..), (:.)(..))
+#if MIN_VERSION_base(4,9,0)
+import Data.Functor.Const
+import Data.Functor.Identity
+import qualified Data.List.NonEmpty as NE
+#endif
+#if MIN_VERSION_base(4,7,0)
+import Data.Proxy
+#endif
 import GHC.Generics
 
 -- | A collection type that can be turned into a list of rendering
@@ -39,9 +47,25 @@ class ToRow a where
 instance ToRow () where
     toRow _ = []
 
+#if MIN_VERSION_base(4,7,0)
+instance ToRow (Proxy a) where
+    toRow _ = []
+#endif
+
 instance (ToField a) => ToRow (Only a) where
     toRow (Only v) = [toField v]
 
+#if MIN_VERSION_base(4,9,0)
+instance (ToField a) => ToRow (Identity a) where
+    toRow (Identity v) = [toField v]
+
+instance (ToField a) => ToRow (Const a b) where
+    toRow (Const v) = [toField v]
+
+instance (ToField a) => ToRow (NE.NonEmpty a) where
+    toRow = toRow . NE.toList
+#endif
+
 instance (ToField a, ToField b) => ToRow (a,b) where
     toRow (a,b) = [toField a, toField b]