src/Rel8/Schema/Spec/ConstrainDBType.hs · rel8

on 11bcbbb help sign in

rel8/src/Rel8/Schema/Spec/ConstrainDBType.hs

35 lines 862 B history raw

1{-# language ConstraintKinds #-}

2{-# language DataKinds #-}

3{-# language FlexibleInstances #-}

4{-# language MultiParamTypeClasses #-}

5{-# language QuantifiedConstraints #-}

6{-# language StandaloneKindSignatures #-}

7{-# language TypeFamilies #-}

8{-# language UndecidableInstances #-}

10module Rel8.Schema.Spec.ConstrainDBType

11 ( ConstrainDBType

12 )

13where

15-- base

16import Data.Kind ( Constraint, Type )

17import Prelude ()

19-- rel8

20import Rel8.Schema.Nullability ( Sql )

21import Rel8.Schema.Spec ( Spec( Spec ) )

24type ConstrainDBType :: (Type -> Constraint) -> Spec -> Constraint

25class

26 ( forall c labels necessity a. ()

27 => (spec ~ 'Spec labels necessity a)

28 => (forall x. (constraint x => c x)) => Sql c a

29 )

30 => ConstrainDBType constraint spec

31instance

32 ( spec ~ 'Spec labels necessity a

33 , Sql constraint a

34 )

35 => ConstrainDBType constraint spec