Add IsSqlValue instance for Maybe, move SqlValue to its own module

Author: anttih

src/Database/Postgres.purs

@@ -3,9 +3,6 @@ module Database.Postgres
   , Client()
   , DB()
   , ConnectionInfo()
-  , SqlValue()
-  , IsSqlValue
-  , toSql
   , connect
   , end
   , execute, execute_
@@ -23,13 +20,14 @@ import Data.Array
 import Data.Foreign
 import Data.Foreign.Class
 import Data.Maybe
-import Data.Int
 import Control.Monad.Aff
 import Control.Monad.Eff.Class
 import Control.Monad.Eff.Exception(Error(), error)
 import Control.Monad.Error.Class (throwError)
 import Data.Traversable (sequence)
 
+import Database.Postgres.SqlValue
+
 newtype Query a = Query String
 
 foreign import data Client :: *
@@ -123,26 +121,6 @@ finally a sequel = do
   sequel
   either throwError pure res
 
-foreign import data SqlValue :: *
-
-foreign import unsafeToSqlValue """
-  function unsafeToSqlValue(x) {
-    return x;
-  }
-  """ :: forall a. a -> SqlValue
-
-class IsSqlValue a where
-  toSql :: a -> SqlValue
-
-instance isSqlValueString :: IsSqlValue String where
-  toSql = unsafeToSqlValue
-
-instance isSqlValueNumber :: IsSqlValue Number where
-  toSql = unsafeToSqlValue
-
-instance isSqlValueInt :: IsSqlValue Int where
-  toSql = unsafeToSqlValue <<< toNumber
-
 
 foreign import connect' """
   function connect$prime(conString) {

src/Database/Postgres/SqlValue.purs

@@ -0,0 +1,34 @@
+module Database.Postgres.SqlValue
+  ( SqlValue()
+  , IsSqlValue
+  , toSql
+  ) where
+
+import Data.Int
+import Data.Maybe
+
+foreign import data SqlValue :: *
+
+class IsSqlValue a where
+  toSql :: a -> SqlValue
+
+instance isSqlValueString :: IsSqlValue String where
+  toSql = unsafeToSqlValue
+
+instance isSqlValueNumber :: IsSqlValue Number where
+  toSql = unsafeToSqlValue
+
+instance isSqlValueInt :: IsSqlValue Int where
+  toSql = unsafeToSqlValue <<< toNumber
+
+instance isSqlValueMaybe :: (IsSqlValue a) => IsSqlValue (Maybe a) where
+  toSql Nothing = nullSqlValue
+  toSql (Just x) = toSql x
+
+foreign import unsafeToSqlValue """
+  function unsafeToSqlValue(x) {
+    return x;
+  }
+  """ :: forall a. a -> SqlValue
+
+foreign import nullSqlValue "var nullSqlValue = null;" :: SqlValue

test/Main.purs

@@ -1,6 +1,7 @@
 module Test.Main where
 
 import Database.Postgres
+import Database.Postgres.SqlValue
 import Debug.Trace
 import Control.Monad.Eff
 import Control.Monad.Eff.Class