src/Rel8/Table/Undefined.hs · rel8

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rel8/src/Rel8/Table/Undefined.hs

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1{-# language FlexibleContexts #-}

2{-# language NamedFieldPuns #-}

3{-# language TypeFamilies #-}

5module Rel8.Table.Undefined

6 ( undefined

7 )

8where

10-- base

11import Prelude hiding ( undefined )

13-- rel8

14import Rel8.Expr ( Expr, Col( E ) )

15import Rel8.Expr.Null ( snull, unsafeUnnullify )

16import Rel8.Schema.HTable ( htabulate, hfield, hspecs )

17import Rel8.Schema.Null ( Nullity( Null, NotNull ) )

18import Rel8.Schema.Spec ( SSpec(..) )

19import Rel8.Table ( Table, fromColumns )

22undefined :: Table Expr a => a

23undefined = fromColumns $ htabulate $ \field -> case hfield hspecs field of

24 SSpec {nullity, info} -> case nullity of

25 Null -> E (snull info)

26 NotNull -> E (unsafeUnnullify (snull info))