Feat: add iter for expressions

sqlglot/expressions.py

@@ -752,12 +752,14 @@ def _binop(self, klass: t.Type[E], other: t.Any, reverse: bool = False) -> E:
             return klass(this=other, expression=this)
         return klass(this=this, expression=other)
 
-    def __getitem__(self, other: ExpOrStr | t.Tuple[ExpOrStr]):
+    def __getitem__(self, other: ExpOrStr | t.Tuple[ExpOrStr]) -> Bracket:
         return Bracket(
             this=self.copy(), expressions=[convert(e, copy=True) for e in ensure_list(other)]
         )
 
-    def __iter__(self):
+    def __iter__(self) -> t.Iterator:
+        if "expressions" in self.arg_types:
+            return iter(self.args.get("expressions") or [])
         # We define this because __getitem__ converts Expression into an iterable, which is
         # problematic because one can hit infinite loops if they do "for x in some_expr: ..."
         # See: https://peps.python.org/pep-0234/

tests/test_expressions.py

@@ -15,8 +15,10 @@ def test_depth(self):
         self.assertEqual(parse_one("x(1)").find(exp.Literal).depth, 1)
 
     def test_iter(self):
+        self.assertEqual([exp.Literal.number(1), exp.Literal.number(2)], list(parse_one("[1, 2]")))
+
         with self.assertRaises(TypeError):
-            for x in parse_one("SELECT 1"):
+            for x in parse_one("1"):
                 pass
 
     def test_eq(self):