opium/lib/Database/PostgreSQL/Opium/ToParamList.hs

63 lines
2.5 KiB
Haskell

{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE TypeOperators #-}
module Database.PostgreSQL.Opium.ToParamList
( ToParamList (..)
) where
import Data.ByteString (ByteString)
import Data.Functor.Identity (Identity)
import Database.PostgreSQL.LibPQ (Format, Oid)
import GHC.Generics (Generic, K1 (..), M1 (..), Rec0, Rep, U1 (..), from, (:*:) (..))
import Database.PostgreSQL.Opium.ToField (ToField (..))
class ToParamList a where
toParamList :: a -> [Maybe (Oid, ByteString, Format)]
default toParamList :: (Generic a, ToParamList' (Rep a)) => a -> [Maybe (Oid, ByteString, Format)]
toParamList = toParamList' . from
instance ToField a => ToParamList [a] where
toParamList = map toField
instance ToParamList () where
instance ToField a => ToParamList (Identity a) where
instance (ToField a, ToField b) => ToParamList (a, b) where
instance (ToField a, ToField b, ToField c) => ToParamList (a, b, c) where
instance (ToField a, ToField b, ToField c, ToField d) => ToParamList (a, b, c, d) where
instance (ToField a, ToField b, ToField c, ToField d, ToField e) => ToParamList (a, b, c, d, e) where
instance (ToField a, ToField b, ToField c, ToField d, ToField e, ToField f) => ToParamList (a, b, c, d, e, f) where
instance (ToField a, ToField b, ToField c, ToField d, ToField e, ToField f, ToField g) => ToParamList (a, b, c, d, e, f, g) where
instance (ToField a, ToField b, ToField c, ToField d, ToField e, ToField f, ToField g, ToField h) => ToParamList (a, b, c, d, e, f, g, h) where
instance (ToField a, ToField b, ToField c, ToField d, ToField e, ToField f, ToField g, ToField h, ToField i) => ToParamList (a, b, c, d, e, f, g, h, i) where
instance (ToField a, ToField b, ToField c, ToField d, ToField e, ToField f, ToField g, ToField h, ToField i, ToField j) => ToParamList (a, b, c, d, e, f, g, h, i, j) where
instance (ToField a, ToField b, ToField c, ToField d, ToField e, ToField f, ToField g, ToField h, ToField i, ToField j, ToField k) => ToParamList (a, b, c, d, e, f, g, h, i, j, k) where
class ToParamList' f where
toParamList' :: f p -> [Maybe (Oid, ByteString, Format)]
instance ToField t => ToParamList' (Rec0 t) where
toParamList' (K1 x) = [toField x]
instance ToParamList' f => ToParamList' (M1 t c f) where
toParamList' (M1 x) = toParamList' x
instance ToParamList' U1 where
toParamList' U1 = []
instance (ToParamList' f, ToParamList' g) => ToParamList' (f :*: g) where
toParamList' (x :*: y) = toParamList' x ++ toParamList' y