restrict parsing of * and X.* as term in expressions

Language/SQL/SimpleSQL/Parse.hs

@@ -604,12 +604,19 @@ simpleLiteral = numberLit <|> stringLit
 === star
 
 used in select *, select x.*, and agg(*) variations, and some other
-places as well. The parser doesn't attempt to check that the star is
-in a valid context, it parses it OK in any scalar expression context.
+places as well. The parser makes an attempt to not parse star in
+most contexts, to provide better experience when the user makes a mistake
+in an expression containing * meaning multiple. It will parse a *
+at the top level of a select item, or in arg in a app argument list.
 -}
 
 star :: Parser ScalarExpr
-star = Star <$ symbol "*"
+star =
+    hidden $ choice
+    [Star <$ symbol "*"
+    -- much easier to use try here than to left factor where
+    -- this is allowed and not allowed
+    ,try (QStar <$> (names <* symbol "." <* symbol "*"))]
 
 {-
 == parameter
@@ -957,12 +964,12 @@ app :: Parser ([Name] -> ScalarExpr)
 app =
     hidden openParen *> choice
     [hidden duplicates
-     <**> (commaSep1 scalarExpr
+     <**> (commaSep1 scalarExprOrStar
            <**> ((hoption [] orderBy <* closeParen)
                  <**> (hoptional afilter <$$$$$> AggregateApp)))
      -- separate cases with no all or distinct which must have at
      -- least one scalar expr
-    ,commaSep1 scalarExpr
+    ,commaSep1 scalarExprOrStar
      <**> choice
           [closeParen *> hidden (choice
                          [window
@@ -1310,13 +1317,19 @@ documenting/fixing.
 scalarExpr :: Parser ScalarExpr
 scalarExpr = label "expression" $ E.makeExprParser term (opTable False)
 
+-- used when parsing contexts where a * or x.* is allowed
+-- currently at the top level of a select item or top level of
+-- argument passed to an app-like. This list may need to be extended.
+
+scalarExprOrStar :: Parser ScalarExpr
+scalarExprOrStar = label "expression" (star <|> scalarExpr)
+
 term :: Parser ScalarExpr
 term = label "expression" $
     choice
     [simpleLiteral
     ,parameter
     ,positionalArg
-    ,star
     ,parensExpr
     ,caseExpr
     ,cast
@@ -1383,8 +1396,12 @@ duplicates =
 -}
 
 selectItem :: Parser (ScalarExpr,Maybe Name)
-selectItem = label "select item" ((,) <$> scalarExpr <*> optional als)
-  where als = label "alias" $ optional (keyword_ "as") *> name
+selectItem =
+    label "select item" $ choice
+    [(,Nothing) <$> star
+    ,(,) <$> scalarExpr <*> optional als]
+  where
+    als = label "alias" $ optional (keyword_ "as") *> name
 
 selectList :: Parser [(ScalarExpr,Maybe Name)]
 selectList = commaSep1 selectItem

Language/SQL/SimpleSQL/Pretty.hs

@@ -87,6 +87,7 @@ scalarExpr _ (IntervalLit s v f t) =
     <+> me (\x -> pretty "to" <+> intervalTypeField x) t
 scalarExpr _ (Iden i) = names i
 scalarExpr _ Star = pretty "*"
+scalarExpr _ (QStar nms) = names nms <> pretty ".*"
 scalarExpr _ Parameter = pretty "?"
 scalarExpr _ (PositionalArg n) = pretty $ T.cons '$' $ showText n
 scalarExpr _ (HostParameter p i) =

Language/SQL/SimpleSQL/Syntax.hs

@@ -105,8 +105,10 @@ data ScalarExpr
 
       -- | identifier with parts separated by dots
     | Iden [Name]
-      -- | star, as in select *, t.*, count(*)
+      -- | star, as in select *, count(*)
     | Star
+      -- | qualified star, as in a.*, b.c.*
+    | QStar [Name]
 
     | Parameter -- ^ Represents a ? in a parameterized query
     | PositionalArg Int -- ^ Represents an e.g. $1 in a parameterized query

expected-parse-errors/golden

@@ -3878,105 +3878,97 @@ expecting expression or query expr
 scalarExpr
 ansi2011
 a >*
-BinOp (Iden [ Name Nothing "a" ]) [ Name Nothing ">" ] Star
+
+1:4:
+  |
+1 | a >*
+  |    ^
+unexpected *
+expecting expression
+
 
 queryExpr
 ansi2011
 select a >*
 
-Select
-  { qeSetQuantifier = SQDefault
-  , qeSelectList =
-      [ ( BinOp (Iden [ Name Nothing "a" ]) [ Name Nothing ">" ] Star
-        , Nothing
-        )
-      ]
-  , qeFrom = []
-  , qeWhere = Nothing
-  , qeGroupBy = []
-  , qeHaving = Nothing
-  , qeOrderBy = []
-  , qeOffset = Nothing
-  , qeFetchFirst = Nothing
-  }
+1:11:
+  |
+1 | select a >*
+  |           ^
+unexpected *
+expecting expression
+
 
 queryExpr
 ansi2011
 select a >*,
 
-1:13:
+1:11:
   |
 1 | select a >*,
   |           ^
-unexpected end of input
-expecting select item
+unexpected *
+expecting expression
 
 
 queryExpr
 ansi2011
 select a >* from
 
-1:17:
+1:11:
   |
 1 | select a >* from
   |           ^
-unexpected end of input
-expecting table ref
+unexpected *
+expecting expression
 
 
 scalarExpr
 ansi2011
 a >* b
 
-1:6:
+1:4:
   |
 1 | a >* b
   |    ^
-unexpected b
+unexpected *
+expecting expression
 
 
 queryExpr
 ansi2011
 select a >* b
 
-Select
-  { qeSetQuantifier = SQDefault
-  , qeSelectList =
-      [ ( BinOp (Iden [ Name Nothing "a" ]) [ Name Nothing ">" ] Star
-        , Just (Name Nothing "b")
-        )
-      ]
-  , qeFrom = []
-  , qeWhere = Nothing
-  , qeGroupBy = []
-  , qeHaving = Nothing
-  , qeOrderBy = []
-  , qeOffset = Nothing
-  , qeFetchFirst = Nothing
-  }
+1:11:
+  |
+1 | select a >* b
+  |           ^
+unexpected *
+expecting expression
+
 
 queryExpr
 ansi2011
 select a >* b,
 
-1:15:
+1:11:
   |
 1 | select a >* b,
   |           ^
-unexpected end of input
-expecting select item
+unexpected *
+expecting expression
 
 
 queryExpr
 ansi2011
 select a >* b from
 
-1:19:
+1:11:
   |
 1 | select a >* b from
   |           ^
-unexpected end of input
-expecting table ref
+unexpected *
+expecting expression
 
 
 scalarExpr
@@ -5147,94 +5139,61 @@ queryExpr
 ansi2011
 select * as a
 
-Select
-  { qeSetQuantifier = SQDefault
-  , qeSelectList = [ ( Star , Just (Name Nothing "a") ) ]
-  , qeFrom = []
-  , qeWhere = Nothing
-  , qeGroupBy = []
-  , qeHaving = Nothing
-  , qeOrderBy = []
-  , qeOffset = Nothing
-  , qeFetchFirst = Nothing
-  }
+1:10:
+  |
+1 | select * as a
+  |          ^^
+unexpected as
+expecting from
+
 
 queryExpr
 ansi2011
 select t.* as a
 
-Select
-  { qeSetQuantifier = SQDefault
-  , qeSelectList =
-      [ ( BinOp (Iden [ Name Nothing "t" ]) [ Name Nothing "." ] Star
-        , Just (Name Nothing "a")
-        )
-      ]
-  , qeFrom = []
-  , qeWhere = Nothing
-  , qeGroupBy = []
-  , qeHaving = Nothing
-  , qeOrderBy = []
-  , qeOffset = Nothing
-  , qeFetchFirst = Nothing
-  }
+1:12:
+  |
+1 | select t.* as a
+  |            ^^
+unexpected as
+expecting from
+
 
 queryExpr
 ansi2011
 select 3 + *
 
-Select
-  { qeSetQuantifier = SQDefault
-  , qeSelectList =
-      [ ( BinOp (NumLit "3") [ Name Nothing "+" ] Star , Nothing ) ]
-  , qeFrom = []
-  , qeWhere = Nothing
-  , qeGroupBy = []
-  , qeHaving = Nothing
-  , qeOrderBy = []
-  , qeOffset = Nothing
-  , qeFetchFirst = Nothing
-  }
+1:12:
+  |
+1 | select 3 + *
+  |            ^
+unexpected *
+expecting expression
+
 
 queryExpr
 ansi2011
 select case when * then 1 end
 
-Select
-  { qeSetQuantifier = SQDefault
-  , qeSelectList =
-      [ ( Case
-            { caseTest = Nothing
-            , caseWhens = [ ( [ Star ] , NumLit "1" ) ]
-            , caseElse = Nothing
-            }
-        , Nothing
-        )
-      ]
-  , qeFrom = []
-  , qeWhere = Nothing
-  , qeGroupBy = []
-  , qeHaving = Nothing
-  , qeOrderBy = []
-  , qeOffset = Nothing
-  , qeFetchFirst = Nothing
-  }
+1:18:
+  |
+1 | select case when * then 1 end
+  |                  ^
+unexpected *
+expecting expression
+
 
 queryExpr
 ansi2011
 select (*)
 
-Select
-  { qeSetQuantifier = SQDefault
-  , qeSelectList = [ ( Parens Star , Nothing ) ]
-  , qeFrom = []
-  , qeWhere = Nothing
-  , qeGroupBy = []
-  , qeHaving = Nothing
-  , qeOrderBy = []
-  , qeOffset = Nothing
-  , qeFetchFirst = Nothing
-  }
+1:9:
+  |
+1 | select (*)
+  |         ^
+unexpected *
+expecting expression or query expr
+
 
 queryExpr
 ansi2011

tests/Language/SQL/SimpleSQL/QueryExprComponents.hs

@@ -73,6 +73,21 @@ selectLists = Group "selectLists"
       [(BinOp (Iden [Name Nothing "a"]) [Name Nothing "+"]
         (BinOp (Iden [Name Nothing "b"]) [Name Nothing "*"] (Iden [Name Nothing "c"]))
        ,Nothing)]}
+    ,q "select * from t"
+     $ toQueryExpr $ makeSelect {msSelectList = [(Star,Nothing)]
+                                ,msFrom = [TRSimple [Name Nothing "t"]]}
+
+    ,q "select t.* from t"
+     $ toQueryExpr $ makeSelect {msSelectList = [(QStar [Name Nothing "t"],Nothing)]
+                                ,msFrom = [TRSimple [Name Nothing "t"]]}
+
+    ,q "select t.*, a as b, u.* from t"
+     $ toQueryExpr $ makeSelect
+        {msSelectList =
+         [(QStar [Name Nothing "t"],Nothing)
+         ,(Iden [Name Nothing "a"], Just $ Name Nothing "b")
+         ,(QStar [Name Nothing "u"],Nothing)]
+        ,msFrom = [TRSimple [Name Nothing "t"]]}
     
     ]
 

tests/Language/SQL/SimpleSQL/SQL2011Queries.hs

@@ -3283,7 +3283,8 @@ querySpecification = Group "query specification"
     ,("select distinct a from t",toQueryExpr $ ms {msSetQuantifier = Distinct})
     ,("select * from t", toQueryExpr $ ms {msSelectList = [(Star,Nothing)]})
     ,("select a.* from t"
-     ,toQueryExpr $ ms {msSelectList = [(BinOp (Iden [Name Nothing "a"]) [Name Nothing "."] Star
+     ,toQueryExpr $ ms {msSelectList =
+                        [(QStar [Name Nothing "a"]
                          ,Nothing)]})
     ,("select a b from t"
      ,toQueryExpr $ ms {msSelectList = [(Iden [Name Nothing "a"], Just $ Name Nothing "b")]})

tests/Language/SQL/SimpleSQL/ScalarExprs.hs

@@ -68,9 +68,8 @@ identifiers = Group "identifiers"
 
 star :: TestItem
 star = Group "star"
-    [t "*" Star
-    --,("t.*", Star2 "t")
-    --,("ROW(t.*,42)", App "ROW" [Star2 "t", NumLit "42"])
+    [t "count(*)" $ App [Name Nothing "count"] [Star]
+    ,t "ROW(t.*,42)" $ App [Name Nothing "ROW"] [QStar [Name Nothing "t"], NumLit "42"]
     ]
 
 parameter :: TestItem
@@ -81,10 +80,8 @@ parameter = Group "parameter"
 dots :: TestItem
 dots = Group "dot"
     [t "t.a" $ Iden [Name Nothing "t",Name Nothing "a"]
-    ,t "t.*" $ BinOp (Iden [Name Nothing "t"]) [Name Nothing "."] Star
     ,t "a.b.c" $ Iden [Name Nothing "a",Name Nothing "b",Name Nothing "c"]
-    ,t "ROW(t.*,42)"
-        $ App [Name Nothing "ROW"] [BinOp (Iden [Name Nothing "t"]) [Name Nothing "."] Star, NumLit "42"]
+    ,t "ROW(t.*,42)" $ App [Name Nothing "ROW"] [QStar [Name Nothing "t"], NumLit "42"]
     ]
 
 app :: TestItem