src/Rel8/Statement/Using.hs · rel8

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1module Rel8.Statement.Using

2 ( ppFrom

3 , ppUsing

4 )

5where

7-- base

8import Prelude

10-- pretty

11import Text.PrettyPrint ( Doc, (<+>), parens, text )

13-- rel8

14import Rel8.Query ( Query )

15import Rel8.Schema.Table ( TableSchema(..), ppTable )

16import Rel8.Statement.Select ( Optimized(..), ppPrimSelect )

19ppFrom :: Query a -> Maybe (Doc, a)

20ppFrom = ppJoin "FROM"

23ppUsing :: Query a -> Maybe (Doc, a)

24ppUsing = ppJoin "USING"

27ppJoin :: String -> Query a -> Maybe (Doc, a)

28ppJoin clause join = do

29 doc <- case ofrom of

30 Empty -> Nothing

31 Unit -> Just mempty

32 Optimized doc -> Just $ text clause <+> parens doc <+> ppTable alias

33 pure (doc, a)

34 where

35 alias = TableSchema {name = "T1", schema = Nothing, columns = ()}

36 (ofrom, a) = ppPrimSelect join