Make BigQuery typeless STRUCTs Expressions

src/sqlfluff/dialects/dialect_ansi.py

@@ -1692,6 +1692,7 @@ class CaseExpressionSegment(BaseSegment):
             Ref("SelectStatementSegment"),
             Ref("LiteralGrammar"),
             Ref("IntervalExpressionSegment"),
+            Ref("TypelessStructSegment"),
             Ref("ColumnReferenceSegment"),
             Sequence(
                 Ref("SimpleArrayTypeGrammar", optional=True), Ref("ArrayLiteralSegment")
@@ -2366,6 +2367,17 @@ class TableEndClauseSegment(BaseSegment):
     match_grammar = Nothing()
 
 
+@ansi_dialect.segment()
+class TypelessStructSegment(BaseSegment):
+    """Expression to construct a STRUCT with implicit types.
+
+    (Yes in BigQuery for example)
+    """
+
+    type = "typeless_struct"
+    match_grammar = Nothing()
+
+
 @ansi_dialect.segment()
 class CreateTableStatementSegment(BaseSegment):
     """A `CREATE TABLE` statement."""

src/sqlfluff/dialects/dialect_bigquery.py

@@ -143,7 +143,6 @@
             Ref("BareFunctionSegment"),
             Ref("FunctionSegment"),
             Ref("ArrayLiteralSegment"),
-            Ref("TypelessStructSegment"),
             Ref("TupleSegment"),
             Ref("BaseExpressionElementGrammar"),
         ),
@@ -168,14 +167,6 @@
             bracket_pairs_set="angle_bracket_pairs",
         ),
     ),
-    # BigQuery also supports the special "Struct" construct.
-    BaseExpressionElementGrammar=ansi_dialect.get_grammar(
-        "BaseExpressionElementGrammar"
-    ).copy(insert=[Ref("TypelessStructSegment")]),
-    FunctionContentsGrammar=ansi_dialect.get_grammar("FunctionContentsGrammar").copy(
-        insert=[Ref("TypelessStructSegment")],
-        before=Ref("ExpressionSegment"),
-    ),
     # BigQuery allows underscore in parameter names, and also anything if quoted in
     # backticks
     ParameterNameSegment=OneOf(
@@ -282,23 +273,6 @@ class UnorderedSelectStatementSegment(BaseSegment):
     )
 
 
-@bigquery_dialect.segment(replace=True)
-class ArrayLiteralSegment(BaseSegment):
-    """Override array literal segment to add Typeless Struct."""
-
-    type = "array_literal"
-    match_grammar = Bracketed(
-        Delimited(
-            OneOf(
-                Ref("ExpressionSegment"),
-                Ref("TypelessStructSegment"),
-            ),
-            optional=True,
-        ),
-        bracket_type="square",
-    )
-
-
 @bigquery_dialect.segment(replace=True)
 class StatementSegment(ansi_dialect.get_segment("StatementSegment")):  # type: ignore
     """Overriding StatementSegment to allow for additional segment parsing."""
@@ -596,7 +570,7 @@ class FunctionParameterListGrammar(BaseSegment):
     )
 
 
-@bigquery_dialect.segment()
+@bigquery_dialect.segment(replace=True)
 class TypelessStructSegment(BaseSegment):
     """Expression to construct a STRUCT with implicit types.
 

test/fixtures/dialects/bigquery/declare_variable.yml

@@ -3,7 +3,7 @@
 # computed by SQLFluff when running the tests. Please run
 # `python test/generate_parse_fixture_yml.py`  to generate them after adding or
 # altering SQL files.
-_hash: 20ea3ed015513907c7b58b9f037cae3464decb55739f78fe5570bf4f4cbff70d
+_hash: b072399d5f83df444e0434bdf9c0b46373debdfb3916e86cc0cb4c1f5118157d
 file:
 - statement:
     declare_segment:
@@ -126,28 +126,30 @@ file:
           data_type_identifier: string
       - end_angle_bracket: '>'
     - keyword: default
-    - typeless_struct:
-        keyword: struct
-        bracketed:
-        - start_bracket: (
-        - literal: "'one'"
-        - comma: ','
-        - literal: "'two'"
-        - end_bracket: )
+    - expression:
+        typeless_struct:
+          keyword: struct
+          bracketed:
+          - start_bracket: (
+          - literal: "'one'"
+          - comma: ','
+          - literal: "'two'"
+          - end_bracket: )
 - statement_terminator: ;
 - statement:
     declare_segment:
     - keyword: declare
     - identifier: str3
     - keyword: default
-    - typeless_struct:
-        keyword: struct
-        bracketed:
-        - start_bracket: (
-        - literal: "'one'"
-        - comma: ','
-        - literal: "'two'"
-        - end_bracket: )
+    - expression:
+        typeless_struct:
+          keyword: struct
+          bracketed:
+          - start_bracket: (
+          - literal: "'one'"
+          - comma: ','
+          - literal: "'two'"
+          - end_bracket: )
 - statement_terminator: ;
 - statement:
     declare_segment:

test/fixtures/dialects/bigquery/select_mixture_of_array_literals.yml

@@ -3,7 +3,7 @@
 # computed by SQLFluff when running the tests. Please run
 # `python test/generate_parse_fixture_yml.py`  to generate them after adding or
 # altering SQL files.
-_hash: 04e1c92046585ea1c067f6c5bfa3c7425fb9518690fb50b45d97c6dadb776d33
+_hash: c47530d353648a4c2b721741e4cd0bc53e351fc10fb4626208198855367c5071
 file:
   statement:
     select_statement:
@@ -91,34 +91,35 @@ file:
           expression:
             array_literal:
               start_square_bracket: '['
-              typeless_struct:
-                keyword: STRUCT
-                bracketed:
-                - start_bracket: (
-                - literal: '"Rudisha"'
-                - alias_expression:
-                    keyword: AS
-                    identifier: name
-                - comma: ','
-                - expression:
-                    array_literal:
-                    - start_square_bracket: '['
-                    - expression:
-                        literal: '23.4'
-                    - comma: ','
-                    - expression:
-                        literal: '26.3'
-                    - comma: ','
-                    - expression:
-                        literal: '26.4'
-                    - comma: ','
-                    - expression:
-                        literal: '26.1'
-                    - end_square_bracket: ']'
-                - alias_expression:
-                    keyword: AS
-                    identifier: splits
-                - end_bracket: )
+              expression:
+                typeless_struct:
+                  keyword: STRUCT
+                  bracketed:
+                  - start_bracket: (
+                  - literal: '"Rudisha"'
+                  - alias_expression:
+                      keyword: AS
+                      identifier: name
+                  - comma: ','
+                  - expression:
+                      array_literal:
+                      - start_square_bracket: '['
+                      - expression:
+                          literal: '23.4'
+                      - comma: ','
+                      - expression:
+                          literal: '26.3'
+                      - comma: ','
+                      - expression:
+                          literal: '26.4'
+                      - comma: ','
+                      - expression:
+                          literal: '26.1'
+                      - end_square_bracket: ']'
+                  - alias_expression:
+                      keyword: AS
+                      identifier: splits
+                  - end_bracket: )
               end_square_bracket: ']'
           alias_expression:
             keyword: AS

test/fixtures/dialects/bigquery/select_struct.yml

@@ -3,7 +3,7 @@
 # computed by SQLFluff when running the tests. Please run
 # `python test/generate_parse_fixture_yml.py`  to generate them after adding or
 # altering SQL files.
-_hash: 958734aacebc6a6c2e7883beca9c39f2491fbbbc1d121987c1fddc014306e7cc
+_hash: 342882573eb2a6a05bd83f11250c9b8bcc24239f0be3a2dd853b5e6f2f006c54
 file:
 - statement:
     select_statement:
@@ -85,26 +85,27 @@ file:
       select_clause:
         keyword: select
         select_clause_element:
-          typeless_struct:
-            keyword: struct
-            bracketed:
-            - start_bracket: (
-            - column_reference:
-              - identifier: bar
-              - dot: .
-              - identifier: bar_id
-            - alias_expression:
-                keyword: as
-                identifier: id
-            - comma: ','
-            - column_reference:
-              - identifier: bar
-              - dot: .
-              - identifier: bar_name
-            - alias_expression:
-                keyword: as
-                identifier: bar
-            - end_bracket: )
+          expression:
+            typeless_struct:
+              keyword: struct
+              bracketed:
+              - start_bracket: (
+              - column_reference:
+                - identifier: bar
+                - dot: .
+                - identifier: bar_id
+              - alias_expression:
+                  keyword: as
+                  identifier: id
+              - comma: ','
+              - column_reference:
+                - identifier: bar
+                - dot: .
+                - identifier: bar_name
+              - alias_expression:
+                  keyword: as
+                  identifier: bar
+              - end_bracket: )
           alias_expression:
             keyword: as
             identifier: bar

test/fixtures/dialects/bigquery/select_typeless_struct_inside_function.yml

@@ -3,30 +3,32 @@
 # computed by SQLFluff when running the tests. Please run
 # `python test/generate_parse_fixture_yml.py`  to generate them after adding or
 # altering SQL files.
-_hash: b0a15006dcb0e8923a1437a02e82b14d9eb3753c6c9be8d835a2c00652a14e22
+_hash: 9c3f1a9ff8303f1c1714ef240d1d9d1b793ff895f8575dca49322892e7325e13
 file:
 - statement:
     select_statement:
       select_clause:
         keyword: SELECT
         select_clause_element:
-          typeless_struct:
-            keyword: STRUCT
-            bracketed:
-              start_bracket: (
-              typeless_struct:
-                keyword: STRUCT
-                bracketed:
-                  start_bracket: (
-                  literal: '1'
-                  alias_expression:
-                    keyword: AS
-                    identifier: b
-                  end_bracket: )
-              alias_expression:
-                keyword: AS
-                identifier: a
-              end_bracket: )
+          expression:
+            typeless_struct:
+              keyword: STRUCT
+              bracketed:
+                start_bracket: (
+                expression:
+                  typeless_struct:
+                    keyword: STRUCT
+                    bracketed:
+                      start_bracket: (
+                      literal: '1'
+                      alias_expression:
+                        keyword: AS
+                        identifier: b
+                      end_bracket: )
+                alias_expression:
+                  keyword: AS
+                  identifier: a
+                end_bracket: )
           alias_expression:
             keyword: AS
             identifier: foo
@@ -41,22 +43,23 @@ file:
               function_name_identifier: ARRAY_AGG
             bracketed:
               start_bracket: (
-              typeless_struct:
-                keyword: STRUCT
-                bracketed:
-                - start_bracket: (
-                - column_reference:
-                    identifier: a
-                - alias_expression:
-                    keyword: AS
-                    identifier: a
-                - comma: ','
-                - column_reference:
-                    identifier: b
-                - alias_expression:
-                    keyword: AS
-                    identifier: b
-                - end_bracket: )
+              expression:
+                typeless_struct:
+                  keyword: STRUCT
+                  bracketed:
+                  - start_bracket: (
+                  - column_reference:
+                      identifier: a
+                  - alias_expression:
+                      keyword: AS
+                      identifier: a
+                  - comma: ','
+                  - column_reference:
+                      identifier: b
+                  - alias_expression:
+                      keyword: AS
+                      identifier: b
+                  - end_bracket: )
               end_bracket: )
       from_clause:
         keyword: FROM

test/fixtures/dialects/bigquery/typeless_struct.sql

@@ -0,0 +1,14 @@
+
+SELECT IF(
+        TRUE,
+        STRUCT('hello' AS greeting, 'world' AS subject),
+        STRUCT('hi' AS greeting, 'there' AS subject)
+    ) AS salute
+FROM (SELECT 1);
+
+SELECT
+  CASE
+    WHEN a.xxx != b.xxx THEN STRUCT(a.xxx AS M, b.xxx AS N)
+  END AS xxx
+FROM A
+JOIN B ON B.id = A.id;