293 lines
9.9 KiB
Plaintext
293 lines
9.9 KiB
Plaintext
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> -- | These is the pretty printing functions, which produce SQL
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> -- source from ASTs. The code attempts to format the output in a
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> -- readable way.
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> module Language.SQL.SimpleSQL.Pretty
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> (prettyQueryExpr
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> ,prettyValueExpr
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> ,prettyQueryExprs
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> ) where
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TODO: there should be more comments in this file, especially the bits
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which have been changed to try to improve the layout of the output.
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> import Language.SQL.SimpleSQL.Syntax
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> import Text.PrettyPrint (render, vcat, text, (<>), (<+>), empty, parens,
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> nest, Doc, punctuate, comma, sep, quotes,
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> doubleQuotes)
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> import Data.Maybe (maybeToList, catMaybes)
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> -- | Convert a query expr ast to concrete syntax.
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> prettyQueryExpr :: QueryExpr -> String
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> prettyQueryExpr = render . queryExpr
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> -- | Convert a value expr ast to concrete syntax.
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> prettyValueExpr :: ValueExpr -> String
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> prettyValueExpr = render . valueExpr
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> -- | Convert a list of query exprs to concrete syntax. A semi colon
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> -- is inserted after each query expr.
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> prettyQueryExprs :: [QueryExpr] -> String
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> prettyQueryExprs = render . vcat . map ((<> text ";\n") . queryExpr)
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= value expressions
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> valueExpr :: ValueExpr -> Doc
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> valueExpr (StringLit s) = quotes $ text $ doubleUpQuotes s
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> where doubleUpQuotes [] = []
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> doubleUpQuotes ('\'':cs) = '\'':'\'':doubleUpQuotes cs
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> doubleUpQuotes (c:cs) = c:doubleUpQuotes cs
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> valueExpr (NumLit s) = text s
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> valueExpr (IntervalLit v u p) =
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> text "interval" <+> quotes (text v)
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> <+> text u
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> <+> maybe empty (parens . text . show ) p
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> valueExpr (Iden i) = name i
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> valueExpr Star = text "*"
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> valueExpr Parameter = text "?"
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> valueExpr (App f es) = name f <> parens (commaSep (map valueExpr es))
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> valueExpr (AggregateApp f d es od) =
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> name f
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> <> parens ((case d of
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> Just Distinct -> text "distinct"
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> Just All -> text "all"
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> Nothing -> empty)
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> <+> commaSep (map valueExpr es)
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> <+> orderBy od)
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> valueExpr (WindowApp f es pb od fr) =
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> name f <> parens (commaSep $ map valueExpr es)
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> <+> text "over"
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> <+> parens ((case pb of
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> [] -> empty
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> _ -> text "partition by"
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> <+> nest 13 (commaSep $ map valueExpr pb))
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> <+> orderBy od
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> <+> maybe empty frd fr)
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> where
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> frd (FrameFrom rs fp) = rsd rs <+> fpd fp
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> frd (FrameBetween rs fps fpe) =
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> rsd rs <+> text "between" <+> fpd fps
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> <+> text "and" <+> fpd fpe
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> rsd rs = case rs of
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> FrameRows -> text "rows"
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> FrameRange -> text "range"
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> fpd UnboundedPreceding = text "unbounded preceding"
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> fpd UnboundedFollowing = text "unbounded following"
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> fpd Current = text "current row"
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> fpd (Preceding e) = valueExpr e <+> text "preceding"
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> fpd (Following e) = valueExpr e <+> text "following"
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> valueExpr (SpecialOp nm [a,b,c]) | nm `elem` [Name "between"
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> ,Name "not between"] =
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> sep [valueExpr a
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> ,name nm <+> valueExpr b
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> ,nest (length (unname nm) + 1) $ text "and" <+> valueExpr c]
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> valueExpr (SpecialOp (Name "rowctor") as) =
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> parens $ commaSep $ map valueExpr as
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> valueExpr (SpecialOp nm es) =
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> name nm <+> parens (commaSep $ map valueExpr es)
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> valueExpr (SpecialOpK nm fs as) =
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> name nm <> parens (sep $ catMaybes
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> (fmap valueExpr fs
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> : map (\(n,e) -> Just (text n <+> valueExpr e)) as))
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> valueExpr (PrefixOp f e) = name f <+> valueExpr e
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> valueExpr (PostfixOp f e) = valueExpr e <+> name f
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> valueExpr e@(BinOp _ op _) | op `elem` [Name "and", Name "or"] =
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> -- special case for and, or, get all the ands so we can vcat them
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> -- nicely
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> case ands e of
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> (e':es) -> vcat (valueExpr e'
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> : map ((name op <+>) . valueExpr) es)
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> [] -> empty -- shouldn't be possible
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> where
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> ands (BinOp a op' b) | op == op' = ands a ++ ands b
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> ands x = [x]
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> -- special case for . we don't use whitespace
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> valueExpr (BinOp e0 (Name ".") e1) =
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> valueExpr e0 <> text "." <> valueExpr e1
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> valueExpr (BinOp e0 f e1) =
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> valueExpr e0 <+> name f <+> valueExpr e1
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> valueExpr (Case t ws els) =
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> sep $ [text "case" <+> maybe empty valueExpr t]
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> ++ map w ws
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> ++ maybeToList (fmap e els)
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> ++ [text "end"]
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> where
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> w (t0,t1) =
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> text "when" <+> nest 5 (commaSep $ map valueExpr t0)
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> <+> text "then" <+> nest 5 (valueExpr t1)
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> e el = text "else" <+> nest 5 (valueExpr el)
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> valueExpr (Parens e) = parens $ valueExpr e
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> valueExpr (Cast e tn) =
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> text "cast" <> parens (sep [valueExpr e
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> ,text "as"
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> ,typeName tn])
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> valueExpr (TypedLit tn s) =
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> typeName tn <+> quotes (text s)
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> valueExpr (SubQueryExpr ty qe) =
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> (case ty of
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> SqSq -> empty
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> SqExists -> text "exists"
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> SqAll -> text "all"
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> SqSome -> text "some"
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> SqAny -> text "any"
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> ) <+> parens (queryExpr qe)
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> valueExpr (In b se x) =
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> valueExpr se <+>
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> (if b then empty else text "not")
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> <+> text "in"
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> <+> parens (nest (if b then 3 else 7) $
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> case x of
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> InList es -> commaSep $ map valueExpr es
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> InQueryExpr qe -> queryExpr qe)
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> unname :: Name -> String
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> unname (QName n) = "\"" ++ n ++ "\""
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> unname (Name n) = n
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> name :: Name -> Doc
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> name (QName n) = doubleQuotes $ text n
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> name (Name n) = text n
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> typeName :: TypeName -> Doc
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> typeName (TypeName t) = text t
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> typeName (PrecTypeName t a) = text t <+> parens (text $ show a)
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> typeName (PrecScaleTypeName t a b) =
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> text t <+> parens (text (show a) <+> comma <+> text (show b))
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= query expressions
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> queryExpr :: QueryExpr -> Doc
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> queryExpr (Select d sl fr wh gb hv od off fe) =
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> sep [text "select"
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> ,case d of
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> All -> empty
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> Distinct -> text "distinct"
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> ,nest 7 $ sep [selectList sl]
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> ,from fr
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> ,maybeValueExpr "where" wh
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> ,grpBy gb
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> ,maybeValueExpr "having" hv
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> ,orderBy od
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> ,maybe empty (\e -> text "offset" <+> valueExpr e <+> text "rows") off
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> ,maybe empty (\e -> text "fetch first" <+> valueExpr e
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> <+> text "rows only") fe
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> ]
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> queryExpr (CombineQueryExpr q1 ct d c q2) =
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> sep [queryExpr q1
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> ,text (case ct of
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> Union -> "union"
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> Intersect -> "intersect"
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> Except -> "except")
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> <+> case d of
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> All -> text "all"
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> Distinct -> empty -- text "distinct"
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> <+> case c of
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> Corresponding -> text "corresponding"
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> Respectively -> empty
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> ,queryExpr q2]
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> queryExpr (With rc withs qe) =
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> text "with" <+> (if rc then text "recursive" else empty)
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> <+> vcat [nest 5
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> (vcat $ punctuate comma $ flip map withs $ \(n,q) ->
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> alias n <+> text "as" <+> parens (queryExpr q))
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> ,queryExpr qe]
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> queryExpr (Values vs) =
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> text "values"
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> <+> nest 7 (commaSep (map (parens . commaSep . map valueExpr) vs))
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> queryExpr (Table t) = text "table" <+> name t
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> alias :: Alias -> Doc
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> alias (Alias nm cols) =
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> text "as" <+> name nm
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> <+> maybe empty (parens . commaSep . map name) cols
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> selectList :: [(ValueExpr,Maybe Name)] -> Doc
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> selectList is = commaSep $ map si is
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> where
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> si (e,al) = valueExpr e <+> maybe empty als al
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> als al = text "as" <+> name al
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> from :: [TableRef] -> Doc
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> from [] = empty
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> from ts =
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> sep [text "from"
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> ,nest 5 $ vcat $ punctuate comma $ map tr ts]
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> where
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> tr (TRSimple t) = name t
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> tr (TRQualified s t) = name s <> text "." <> name t
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> tr (TRLateral t) = text "lateral" <+> tr t
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> tr (TRFunction f as) =
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> name f <> parens (commaSep $ map valueExpr as)
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> tr (TRAlias t a) = sep [tr t, alias a]
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> tr (TRParens t) = parens $ tr t
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> tr (TRQueryExpr q) = parens $ queryExpr q
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> tr (TRJoin t0 jt t1 jc) =
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> sep [tr t0
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> ,joinText jt jc <+> tr t1
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> ,joinCond jc]
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> joinText jt jc =
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> sep [case jc of
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> Just JoinNatural -> text "natural"
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> _ -> empty
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> ,case jt of
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> JInner -> text "inner"
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> JLeft -> text "left"
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> JRight -> text "right"
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> JFull -> text "full"
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> JCross -> text "cross"
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> ,text "join"]
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> joinCond (Just (JoinOn e)) = text "on" <+> valueExpr e
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> joinCond (Just (JoinUsing es)) =
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> text "using" <+> parens (commaSep $ map name es)
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> joinCond Nothing = empty
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> joinCond (Just JoinNatural) = empty
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> maybeValueExpr :: String -> Maybe ValueExpr -> Doc
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> maybeValueExpr k = maybe empty
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> (\e -> sep [text k
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> ,nest (length k + 1) $ valueExpr e])
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> grpBy :: [GroupingExpr] -> Doc
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> grpBy [] = empty
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> grpBy gs = sep [text "group by"
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> ,nest 9 $ commaSep $ map ge gs]
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> where
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> ge (SimpleGroup e) = valueExpr e
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> ge (GroupingParens g) = parens (commaSep $ map ge g)
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> ge (Cube es) = text "cube" <> parens (commaSep $ map ge es)
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> ge (Rollup es) = text "rollup" <> parens (commaSep $ map ge es)
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> ge (GroupingSets es) = text "grouping sets" <> parens (commaSep $ map ge es)
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> orderBy :: [SortSpec] -> Doc
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> orderBy [] = empty
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> orderBy os = sep [text "order by"
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> ,nest 9 $ commaSep $ map f os]
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> where
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> f (SortSpec e d n) =
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> valueExpr e
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> <+> (if d == Asc then empty else text "desc")
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> <+> (case n of
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> NullsOrderDefault -> empty
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> NullsFirst -> text "nulls" <+> text "first"
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> NullsLast -> text "nulls" <+> text "last")
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= utils
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> commaSep :: [Doc] -> Doc
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> commaSep ds = sep $ punctuate comma ds
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