aa44873 · typeable/postgresql-simple

git.iko.soy/typeable/postgresql-simple

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Code for "instance Result Null"

aa44873Leon P Smith15 years ago

src/Database/PostgreSQL/Simple/Result.hs+5−1

@@ -48,7 +48,7 @@ import Data.Word (Word64)

48import Database.PostgreSQL.Simple.Internal

49import Database.PostgreSQL.Simple.Field (Field(..), RawResult(..))

50import Database.PostgreSQL.Simple.BuiltinTypes

51−import Database.PostgreSQL.Simple.Types (Binary(..))

51+import Database.PostgreSQL.Simple.Types (Binary(..), Null(..))

52import qualified Database.PostgreSQL.LibPQ as PQ

53import System.IO.Unsafe (unsafePerformIO)

54import System.Locale (defaultTimeLocale)

@@ -98,6 +98,10 @@ instance (Result a) => Result (Maybe a) where

98 convert _ Nothing = pure Nothing

99 convert f bs = Just <$> convert f bs

100

101+instance Result Null where

102+ convert _ Nothing = pure Null

103+ convert f (Just _) = returnError ConversionFailed f "data is not null"

104+

101instance Result Bool where

105instance Result Bool where

102 convert f bs

106 convert f bs

103 | typeOid f /= builtin2oid Bool = returnError Incompatible f ""

107 | typeOid f /= builtin2oid Bool = returnError Incompatible f ""