feat: Introduce meta comment to parse known functions as exp.Anonymous (

#4532)

* feat: Introduce meta comment to parse known functions as exp.Anonymous

* PR Feedback 1

* Make flag case sensitive

* Change to sqlglot.anonymous

sqlglot/expressions.py

@@ -59,6 +59,7 @@ def __new__(cls, clsname, bases, attrs):
 
 
 SQLGLOT_META = "sqlglot.meta"
+SQLGLOT_ANONYMOUS = "sqlglot.anonymous"
 TABLE_PARTS = ("this", "db", "catalog")
 COLUMN_PARTS = ("this", "table", "db", "catalog")
 

sqlglot/parser.py

@@ -5361,6 +5361,16 @@ def _parse_function_call(
             alias = not known_function or upper in self.FUNCTIONS_WITH_ALIASED_ARGS
             args = self._parse_csv(lambda: self._parse_lambda(alias=alias))
 
+            post_func_comments = self._curr and self._curr.comments
+            if known_function and post_func_comments:
+                # If the user-inputted comment "/* sqlglot.anonymous */" is following the function
+                # call we'll construct it as exp.Anonymous, even if it's "known"
+                if any(
+                    comment.lstrip().startswith(exp.SQLGLOT_ANONYMOUS)
+                    for comment in post_func_comments
+                ):
+                    known_function = False
+
             if alias and known_function:
                 args = self._kv_to_prop_eq(args)
 

tests/test_parser.py

@@ -888,3 +888,15 @@ def test_drop_column(self):
         ast = parse_one("ALTER TABLE tbl DROP COLUMN col")
         self.assertEqual(len(list(ast.find_all(exp.Table))), 1)
         self.assertEqual(len(list(ast.find_all(exp.Column))), 1)
+
+    def test_udf_meta(self):
+        ast = parse_one("YEAR(a) /* sqlglot.anonymous */")
+        self.assertIsInstance(ast, exp.Anonymous)
+
+        # Meta flag is case sensitive
+        ast = parse_one("YEAR(a) /* sqlglot.anONymous */")
+        self.assertIsInstance(ast, exp.Year)
+
+        # Incomplete or incorrect anonymous meta comments are not registered
+        ast = parse_one("YEAR(a) /* sqlglot.anon */")
+        self.assertIsInstance(ast, exp.Year)