src/Rel8/Schema/Field.hs · rel8

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1{-# language DataKinds #-}

2{-# language StandaloneKindSignatures #-}

3{-# language TypeFamilies #-}

4{-# language UndecidableInstances #-}

6module Rel8.Schema.Field

7 ( Field

8 )

9where

11-- base

12import Data.Functor.Identity ( Identity )

13import Data.Kind ( Type )

14import Prelude

16-- rel8

17import Rel8.Aggregate ( Aggregate )

18import Rel8.Expr ( Expr )

19import Rel8.Kind.Labels ( Labels )

20import Rel8.Kind.Necessity ( Necessity( Required, Optional ) )

21import Rel8.Schema.Context ( Insertion, IsSpecialContext )

22import qualified Rel8.Schema.Kind as K

23import Rel8.Schema.Spec ( Spec( Spec ) )

24import Rel8.Schema.Structure ( Structure, Shape( Column ), Shape1 )

27type IField :: Bool -> K.Context -> Labels -> Necessity -> Type -> Type -> Type

28type family IField isSpecialContext labels context necessity db a where

29 IField 'False context _labels _necessity _db a = context a

30 IField 'True Identity _labels _necessity _db a = a

31 IField 'True Expr _labels _necessity _db a = Expr a

32 IField 'True Insertion _labels 'Required _db a = Expr a

33 IField 'True Insertion _labels 'Optional _db a = Maybe (Expr a)

34 IField 'True Aggregate _labels _necessity _db a = Aggregate (Expr a)

35 IField 'True Structure labels necessity db a = Shape1 'Column ('Spec labels necessity db a)

38type Field :: K.Context -> Labels -> Necessity -> Type -> Type -> Type

39type Field context labels necessity db a =

40 IField (IsSpecialContext context) context labels necessity db a