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

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

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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.ConstrainType

11 ( ConstrainType

12 )

13where

15-- base

16import Data.Kind ( Constraint, Type )

17import Prelude ()

19-- rel8

20import Rel8.Schema.Spec ( Spec( Spec ) )

23type ConstrainType :: (Type -> Constraint) -> Spec -> Constraint

24class

25 ( forall labels necessity db a. ()

26 => (spec ~ 'Spec labels necessity db a)

27 => constraint a

28 ) =>

29 ConstrainType constraint spec

30instance (spec ~ 'Spec labels necessity db a, constraint a) =>

31 ConstrainType constraint spec