src/Rel8/Query/List.hs · rel8

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1{-# language FlexibleContexts #-}

3module Rel8.Query.List

4 ( many, some

5 )

6where

8-- base

9import Prelude

11-- rel8

12import Rel8.Query ( Query )

13import Rel8.Query.Aggregate ( aggregate )

14import Rel8.Query.Maybe ( optional )

15import Rel8.Schema.Context ( DB )

16import Rel8.Table ( Table )

17import Rel8.Table.Aggregate ( listAgg, nonEmptyAgg )

18import Rel8.Table.List ( ListTable )

19import Rel8.Table.Maybe ( maybeTable )

20import Rel8.Table.NonEmpty ( NonEmptyTable )

23some :: Table DB a => Query a -> Query (NonEmptyTable a)

24some = aggregate . fmap nonEmptyAgg

27many :: Table DB a => Query a -> Query (ListTable a)

28many = fmap (maybeTable mempty id) . optional . aggregate . fmap listAgg