Fixup grammar: subquery as function argument

Author: georgestagg

tree-sitter-ggsql/grammar.js

@@ -173,6 +173,17 @@ module.exports = grammar({
       ')'
     )),
 
+    // Scalar subquery for use inside expressions (e.g. function arguments)
+    // Matches (SELECT ...) or (WITH ... SELECT ...),
+    scalar_subquery: $ => prec(2, seq(
+      '(',
+      choice(
+        $.with_statement,
+        $.select_statement,
+      ),
+      ')'
+    )),
+
     // Token-by-token fallback for any other subquery content
     subquery_body: $ => repeat1(choice(
       $.window_function,
@@ -311,6 +322,8 @@ module.exports = grammar({
       $.cast_expression,
       // Nested function call
       $.function_call,
+      // Scalar subquery: (SELECT ...) or (WITH ... SELECT ...)
+      $.scalar_subquery,
       // Arithmetic/comparison expression (binary operators)
       seq($.positional_arg, choice('+', '-', '*', '/', '%', '||', '::', '<', '>', '<=', '>=', '=', '!=', '<>'), $.positional_arg),
       // Parenthesized expression

tree-sitter-ggsql/test/corpus/basic.txt

@@ -2485,6 +2485,75 @@ SELECT SUM(TRY_CAST(price AS INTEGER)) as total FROM data VISUALISE DRAW bar MAP
                       (bare_identifier))))
                 name: (aesthetic_name)))))))))
 
+================================================================================
+Scalar subquery as function argument
+================================================================================
+
+SELECT LEAST(SQRT(x), (SELECT MAX(y) FROM t)) FROM data
+VISUALISE
+DRAW point MAPPING x AS x
+
+--------------------------------------------------------------------------------
+
+(query
+  (sql_portion
+    (sql_statement
+      (select_statement
+        (select_body
+          (function_call
+            (identifier
+              (bare_identifier))
+            (function_args
+              (function_arg
+                (positional_arg
+                  (function_call
+                    (identifier
+                      (bare_identifier))
+                    (function_args
+                      (function_arg
+                        (positional_arg
+                          (qualified_name
+                            (identifier
+                              (bare_identifier)))))))))
+              (function_arg
+                (positional_arg
+                  (scalar_subquery
+                    (select_statement
+                      (select_body
+                        (function_call
+                          (identifier
+                            (bare_identifier))
+                          (function_args
+                            (function_arg
+                              (positional_arg
+                                (qualified_name
+                                  (identifier
+                                    (bare_identifier)))))))
+                        (from_clause
+                          (table_ref
+                            table: (qualified_name
+                              (identifier
+                                (bare_identifier))))))))))))
+          (from_clause
+            (table_ref
+              table: (qualified_name
+                (identifier
+                  (bare_identifier)))))))))
+  (visualise_statement
+    (visualise_keyword)
+    (viz_clause
+      (draw_clause
+        (geom_type)
+        (mapping_clause
+          (mapping_list
+            (mapping_element
+              (explicit_mapping
+                value: (mapping_value
+                  (column_reference
+                    (identifier
+                      (bare_identifier))))
+                name: (aesthetic_name)))))))))
+
 ================================================================================
 FACET single variable (wrap layout)
 ================================================================================