src/Rel8/Column/List.hs · rel8

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1{-# language DataKinds #-}

2{-# language StandaloneKindSignatures #-}

3{-# language TypeFamilyDependencies #-}

5module Rel8.Column.List

6 ( HList

7 )

8where

10-- base

11import Data.Kind ( Type )

12import Prelude ()

14-- rel8

15import qualified Rel8.Schema.Kind as K

16import Rel8.Schema.Result ( Result )

17import Rel8.Table.List ( ListTable )

20-- | Nest a list within a 'Rel8able'. @HList f a@ will produce a 'ListTable'

21-- @a@ in the 'Expr' context, and a @[a]@ in the 'Result' context.

22type HList :: K.Context -> Type -> Type

23type family HList context = list | list -> context where

24 HList Result = []

25 HList context = ListTable context