persistable-record: apply and export generic tuple templates.

persistable-record/persistable-record.cabal

@@ -27,6 +27,7 @@ library
                         Database.Record.FromSql
                         Database.Record.ToSql
                         Database.Record.Persistable
+                        Database.Record.TupleInstances
                         Database.Record.Instances
                         Database.Record.KeyConstraint
                         Database.Record

persistable-record/src/Database/Record.hs

@@ -48,6 +48,7 @@ import Database.Record.ToSql
   (ToSqlM, RecordToSql, ToSql(..), valueRecordToSql,
    runFromRecord, wrapToSql, putRecord, putEmpty, fromRecord,
    updateValuesByUnique, updateValuesByPrimary)
+import Database.Record.TupleInstances ()
 
 {- $concepts
 On most drivers for SQL database,

persistable-record/src/Database/Record/FromSql.hs

@@ -152,10 +152,6 @@ instance FromSql q a => GFromSql q (K1 i a) where
   gFromSql = K1 <$> recordFromSql
 
 
--- | Inference rule of 'RecordFromSql' proof object which can convert
---   from list of SQL type ['q'] into Haskell tuple ('a', 'b') type.
-instance (FromSql q a, FromSql q b) => FromSql q (a, b)  -- default generic instance
-
 -- | Inference rule of 'RecordFromSql' proof object which can convert
 --   from list of SQL type ['q'] into Haskell 'Maybe' type.
 instance (HasColumnConstraint NotNull a, FromSql q a, PersistableType q)

persistable-record/src/Database/Record/Persistable.hs

@@ -147,9 +147,6 @@ genericFieldOffsets :: (Generic a, GFieldWidthList (Rep a)) => ProductConst (Arr
 genericFieldOffsets = pmapConst (offsets . DList.toList) $ to `pmap` gFieldWidthList
 
 
--- | Inference rule of 'PersistableRecordWidth' proof object for tuple ('a', 'b') type.
-instance (PersistableWidth a, PersistableWidth b) => PersistableWidth (a, b)  -- default generic instance
-
 -- | Inference rule of 'PersistableRecordWidth' proof object for 'Maybe' type.
 instance PersistableWidth a => PersistableWidth (Maybe a) where
   persistableWidth = maybeWidth persistableWidth

persistable-record/src/Database/Record/TH.hs

@@ -56,7 +56,10 @@ module Database.Record.TH (
   persistableFunctionNamesDefault,
 
   -- * Not nullable single column type
-  deriveNotNullType
+  deriveNotNullType,
+
+  -- * Template for tuple types
+  defineTupleInstances,
   ) where
 
 import GHC.Generics (Generic)
@@ -87,6 +90,7 @@ import Database.Record.Persistable
   (runPersistableRecordWidth,
    ProductConst, getProductConst, genericFieldOffsets)
 import qualified Database.Record.Persistable as Persistable
+import Database.Record.InternalTH (defineTupleInstances)
 
 
 -- | 'NameConfig' type to customize names of expanded record templates.

persistable-record/src/Database/Record/ToSql.hs

@@ -126,10 +126,6 @@ instance ToSql q a => GToSql q (K1 i a) where
   gToSql = (\(K1 a) -> a) `mapToSql` recordToSql
 
 
--- | Inference rule of 'RecordToSql' proof object which can convert
---   from Haskell tuple ('a', 'b') type into list of SQL type ['q'].
-instance (ToSql q a, ToSql q b) => ToSql q (a, b)  -- default generic instance
-
 -- | Inference rule of 'RecordToSql' proof object which can convert
 --   from Haskell 'Maybe' type into list of SQL type ['q'].
 instance (PersistableType q, PersistableWidth a, ToSql q a) => ToSql q (Maybe a)  where

persistable-record/src/Database/Record/TupleInstances.hs

@@ -0,0 +1,13 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances #-}
+
+module Database.Record.TupleInstances () where
+
+import Control.Applicative ((<$>))
+
+import Database.Record.InternalTH (defineTupleInstances)
+
+
+$(concat <$> mapM defineTupleInstances [2..7])
+-- Generic instances of tuple types are generated from 2 to 7 in GHC.Generics.