src/Rel8/Expr/Serialize.hs · rel8

on 03b366b help sign in

rel8/src/Rel8/Expr/Serialize.hs

47 lines 1.3 kB history raw

1{-# language NamedFieldPuns #-}

2{-# language TypeFamilies #-}

4module Rel8.Expr.Serialize

5 ( litExpr

6 , slitExpr

7 , sparseValue

8 )

9where

11-- base

12import Prelude

14-- hasql

15import qualified Hasql.Decoders as Hasql

17-- opaleye

18import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye

20-- rel8

21import {-# SOURCE #-} Rel8.Expr ( Expr( Expr ) )

22import Rel8.Expr.Opaleye ( scastExpr )

23import Rel8.Schema.Nullability

24 ( Nullability( Nullable, NonNullable )

25 , Nullabilizes, nullabilization

26 )

27import Rel8.Type ( DBType, typeInformation )

28import Rel8.Type.Information ( TypeInformation(..) )

31litExpr :: (DBType db, Nullabilizes db a) => a -> Expr a

32litExpr = slitExpr nullabilization typeInformation

35slitExpr :: Nullability db a -> TypeInformation db -> a -> Expr a

36slitExpr nullable info@TypeInformation {encode} =

37 scastExpr nullable info . Expr . encoder

38 where

39 encoder = case nullable of

40 Nullable -> maybe (Opaleye.ConstExpr Opaleye.NullLit) encode

41 NonNullable -> encode

44sparseValue :: Nullability db a -> TypeInformation db -> Hasql.Row a

45sparseValue nullability TypeInformation {decode, out} = case nullability of

46 Nullable -> Hasql.column $ Hasql.nullable $ out <$> decode

47 NonNullable -> Hasql.column $ Hasql.nonNullable $ out <$> decode