partial support for lateral

Language/SQL/SimpleSQL/Parser.lhs

@@ -505,6 +505,7 @@ tref
 >     tref = nonJoinTref >>= optionSuffix joinTrefSuffix
 >     nonJoinTref = choice [try (TRQueryExpr <$> parens queryExpr)
 >                          ,TRParens <$> parens tref
+>                          ,TRLateral <$> (try (keyword_ "lateral") *> tref)
 >                          ,try (TRFunction <$> identifierString
 >                                           <*> parens (commaSep scalarExpr))
 >                          ,TRSimple <$> identifierString]
@@ -690,7 +691,7 @@ keyword parser also
 >     ["select", "as", "from", "where", "having", "group", "order"
 >     ,"limit", "offset"
 >     ,"inner", "left", "right", "full", "natural", "join"
->     ,"cross", "on", "using"
+>     ,"cross", "on", "using", "lateral"
 >     ,"when", "then", "case", "end", "in"
 >     ,"except", "intersect", "union"]
 

Language/SQL/SimpleSQL/Pretty.lhs

@@ -182,6 +182,7 @@
 >         ,nest 5 $ vcat $ punctuate comma $ map tr ts]
 >   where
 >     tr (TRSimple t) = text t
+>     tr (TRLateral t) = text "lateral" <+> tr t
 >     tr (TRFunction f as) =
 >         text f <> parens (commaSep $ map scalarExpr as)
 >     tr (TRAlias t a cs) =

Language/SQL/SimpleSQL/Syntax.lhs

@@ -197,6 +197,8 @@ I'm not sure if this is valid syntax or not.
 >               | TRQueryExpr QueryExpr
 >                 -- | from function(args)
 >               | TRFunction String [ScalarExpr]
+>                 -- | from lateral t
+>               | TRLateral TableRef
 >                 deriving (Eq,Show,Read)
 
 TODO: add function table ref

tools/Language/SQL/SimpleSQL/Postgres.lhs

@@ -51,7 +51,7 @@ queries section
 >     ,"SELECT * FROM people AS mother JOIN people AS child ON mother.id = child.mother_id;"
 >     ,"SELECT * FROM my_table AS a CROSS JOIN my_table AS b;"
 >     ,"SELECT * FROM (my_table AS a CROSS JOIN my_table) AS b;"
->     ,"SELECT * FROM getfoo(1) AS t1;" -- function tableref
+>     ,"SELECT * FROM getfoo(1) AS t1;"
 >     ,"SELECT * FROM foo\n\
 >      \    WHERE foosubid IN (\n\
 >      \                        SELECT foosubid\n\
@@ -63,23 +63,23 @@ queries section
 >      \      AS t1(proname name, prosrc text)\n\
 >      \    WHERE proname LIKE 'bytea%';"-} -- types in the alias??
 
->     --,"SELECT * FROM foo, LATERAL (SELECT * FROM bar WHERE bar.id = foo.bar_id) ss;" -- lateral
+>     ,"SELECT * FROM foo, LATERAL (SELECT * FROM bar WHERE bar.id = foo.bar_id) ss;" -- lateral
 >     ,"SELECT * FROM foo, bar WHERE bar.id = foo.bar_id;"
 
 >     {-,"SELECT p1.id, p2.id, v1, v2\n\
 >      \FROM polygons p1, polygons p2,\n\
 >      \     LATERAL vertices(p1.poly) v1,\n\
 >      \     LATERAL vertices(p2.poly) v2\n\
->      \WHERE (v1 <-> v2) < 10 AND p1.id != p2.id;"-} -- <-> operator?, lateral
+>      \WHERE (v1 <-> v2) < 10 AND p1.id != p2.id;"-} -- <-> operator?
 
 >     {-,"SELECT p1.id, p2.id, v1, v2\n\
 >      \FROM polygons p1 CROSS JOIN LATERAL vertices(p1.poly) v1,\n\
 >      \     polygons p2 CROSS JOIN LATERAL vertices(p2.poly) v2\n\
 >      \WHERE (v1 <-> v2) < 10 AND p1.id != p2.id;"-}
 
->     {-,"SELECT m.name\n\
+>     ,"SELECT m.name\n\
 >      \FROM manufacturers m LEFT JOIN LATERAL get_product_names(m.id) pname ON true\n\
->      \WHERE pname IS NULL;"-} -- lateral, function ref
+>      \WHERE pname IS NULL;"
 
 
 >     ,"SELECT * FROM fdt WHERE c1 > 5"
@@ -253,11 +253,11 @@ select page reference
 >      \  )\n\
 >      \SELECT distance, employee_name FROM employee_recursive;"-} -- with recursive, full cte alias
 
->     {-,"SELECT m.name AS mname, pname\n\
+>     ,"SELECT m.name AS mname, pname\n\
 >      \FROM manufacturers m, LATERAL get_product_names(m.id) pname;"
 
 >     ,"SELECT m.name AS mname, pname\n\
->      \FROM manufacturers m LEFT JOIN LATERAL get_product_names(m.id) pname ON true;"-} -- lateral
+>      \FROM manufacturers m LEFT JOIN LATERAL get_product_names(m.id) pname ON true;"
 
 >     ,"SELECT 2+2;"
 

tools/Language/SQL/SimpleSQL/TableRefs.lhs

@@ -19,6 +19,30 @@ expression
 >     ,("select a from t,u"
 >      ,ms [TRSimple "t", TRSimple "u"])
 
+these lateral queries make no sense but the syntax is valid
+
+>     ,("select a from lateral a"
+>      ,ms [TRLateral $ TRSimple "a"])
+
+>     ,("select a from lateral a,b"
+>      ,ms [TRLateral $ TRSimple "a", TRSimple "b"])
+
+>     -- not sure what the problem is
+>     --,("select from a, lateral b"
+>     -- ,ms [TRSimple "a", TRLateral $ TRSimple "b"])
+
+>     ,("select a from a natural join lateral b"
+>      ,ms [TRJoin (TRSimple "a") JInner
+>                  (TRLateral $ TRSimple "b")
+>                  (Just JoinNatural)])
+
+>     -- the lateral binds on the outside of the join which is incorrect
+>     --,("select a from lateral a natural join lateral b"
+>     -- ,ms [TRJoin (TRLateral $ TRSimple "a") JInner
+>     --             (TRLateral $ TRSimple "b")
+>     --             (Just JoinNatural)])
+
+
 >     ,("select a from t inner join u on expr"
 >      ,ms [TRJoin (TRSimple "t") JInner (TRSimple "u")
 >                        (Just $ JoinOn $ Iden "expr")])