diff --git a/tatsu/bootstrap.py b/tatsu/bootstrap.py
index 84e5205..ed5aff8 100644
--- a/tatsu/bootstrap.py
+++ b/tatsu/bootstrap.py
@@ -11,6 +11,8 @@
 
 # ruff: noqa: C405, COM812, I001, F401, PLR1702, PLC2801, SIM117
 
+from __future__ import annotations
+
 import sys
 from pathlib import Path
 
diff --git a/tatsu/collections/orderedset.py b/tatsu/collections/orderedset.py
index fb92401..3c12190 100644
--- a/tatsu/collections/orderedset.py
+++ b/tatsu/collections/orderedset.py
@@ -1,14 +1,13 @@
 # NOTE: from https://github.com/LuminosoInsight/ordered-set/blob/master/ordered_set.py
+from __future__ import annotations
+
 import itertools
 from collections.abc import (
-    Iterable,
     Iterator,
     Mapping,
     MutableSequence,
-    MutableSet,
-    Sequence,
 )
-from typing import Any, TypeVar
+from typing import Any, Iterable, MutableSet, Sequence, TypeVar
 
 T = TypeVar('T')
 
@@ -32,7 +31,7 @@ def __getitem__(self, i):
             self._list_cache = list(self._map.keys())
         return self._list_cache[i]
 
-    def copy(self) -> 'OrderedSet[T]':
+    def copy(self) -> OrderedSet[T]:
         return self.__class__(self)
 
     def __getstate__(self):
@@ -81,25 +80,25 @@ def __repr__(self) -> str:
     def __eq__(self, other: Any) -> bool:
         return all(item in other for item in self)
 
-    def union(self, *other: Iterable[T]) -> 'OrderedSet[T]':
+    def union(self, *other: Iterable[T]) -> OrderedSet[T]:
         # do not split `str`
         outer = tuple(
-            [o] if not isinstance(o, set | Mapping | MutableSequence) else o
+            [o] if not isinstance(o, (set, Mapping, MutableSequence)) else o
             for o in other
         )
         inner = itertools.chain([self], *outer)
         items = itertools.chain.from_iterable(inner)
         return type(self)(itertools.chain(items))
 
-    def __and__(self, other: Iterable[Iterable[T]]) -> 'OrderedSet[T]':
+    def __and__(self, other: Iterable[Iterable[T]]) -> OrderedSet[T]:
         return self.intersection(other)
 
-    def intersection(self, *other: Iterable[Iterable[T]]) -> 'OrderedSet[T]':
+    def intersection(self, *other: Iterable[Iterable[T]]) -> OrderedSet[T]:
         common = set.intersection(*other)  # type: ignore[var-annotated, arg-type]
         items = (item for item in self if item in common)
         return type(self)(items)
 
-    def difference(self, *other: Iterable[T]) -> 'OrderedSet[T]':
+    def difference(self, *other: Iterable[T]) -> OrderedSet[T]:
         other = set.union(*other)  # type: ignore[assignment, arg-type]
         items = (item for item in self if item not in other)
         return type(self)(items)
@@ -112,7 +111,7 @@ def issuperset(self, other: set[T]) -> bool:
             return False
         return all(item in self for item in other)
 
-    def symmetric_difference(self, other: set[T]) -> 'OrderedSet[T]':
+    def symmetric_difference(self, other: set[T]) -> OrderedSet[T]:
         cls = type(self)
         diff1 = cls(self).difference(other)
         diff2 = cls(other).difference(self)
diff --git a/tatsu/g2e/semantics.py b/tatsu/g2e/semantics.py
index ccf0b49..0956af0 100644
--- a/tatsu/g2e/semantics.py
+++ b/tatsu/g2e/semantics.py
@@ -85,12 +85,12 @@ def syntactic_predicate(self, ast):
         return None
 
     def optional(self, ast):
-        if isinstance(ast, model.Group | model.Optional | model.Closure):
+        if isinstance(ast, (model.Group, model.Optional, model.Closure)):
             ast = ast.exp
         return model.Optional(ast)
 
     def closure(self, ast):
-        if isinstance(ast, model.Group | model.Optional):
+        if isinstance(ast, (model.Group, model.Optional)):
             ast = ast.exp
         return model.Closure(ast)
 
diff --git a/tatsu/grammars.py b/tatsu/grammars.py
index 4ac6c12..7c3fa4e 100644
--- a/tatsu/grammars.py
+++ b/tatsu/grammars.py
@@ -865,7 +865,7 @@ def _nullable(self):
 
     @staticmethod
     def param_repr(p):
-        if isinstance(p, int | float) or (isinstance(p, str) and p.isalnum()):
+        if isinstance(p, (int, float)) or (isinstance(p, str) and p.isalnum()):
             return str(p)
         else:
             return repr(p)
diff --git a/tatsu/infos.py b/tatsu/infos.py
index 876a96c..909a682 100644
--- a/tatsu/infos.py
+++ b/tatsu/infos.py
@@ -3,6 +3,7 @@
 import copy
 import dataclasses
 import re
+import sys
 from collections.abc import Callable, MutableMapping
 from itertools import starmap
 from typing import Any, NamedTuple
@@ -12,6 +13,12 @@
 from .util.misc import cached_re_compile
 from .util.unicode_characters import C_DERIVE
 
+if sys.version_info < (3, 10):
+    import builtins
+
+    def zip(*iterables, strict=False):
+        return builtins.zip(*iterables)
+
 
 class UndefinedStr(str):
     pass
@@ -261,7 +268,7 @@ class RuleResult(NamedTuple):
     newstate: Any
 
 
-@dataclasses.dataclass(slots=True)
+@dataclasses.dataclass(**({'slots': True} if sys.version_info >= (3, 10) else {}))
 class ParseState:
     pos: int = 0
     ast: AST = dataclasses.field(default_factory=AST)
diff --git a/tatsu/mixins/indent.py b/tatsu/mixins/indent.py
index e1026a7..c982d5e 100644
--- a/tatsu/mixins/indent.py
+++ b/tatsu/mixins/indent.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import io
 from contextlib import contextmanager
 
diff --git a/tatsu/ngcodegen/objectmodel.py b/tatsu/ngcodegen/objectmodel.py
index f67e527..6fa0c1a 100644
--- a/tatsu/ngcodegen/objectmodel.py
+++ b/tatsu/ngcodegen/objectmodel.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import builtins
 from collections import namedtuple
 
diff --git a/tatsu/ngcodegen/python.py b/tatsu/ngcodegen/python.py
index 7658337..791c691 100644
--- a/tatsu/ngcodegen/python.py
+++ b/tatsu/ngcodegen/python.py
@@ -27,6 +27,8 @@
 
     # ruff: noqa: C405, COM812, I001, F401, PLR1702, PLC2801, SIM117
 
+    from __future__ import annotations
+
     import sys
     from pathlib import Path
 
@@ -94,7 +96,7 @@ def walk_Grammar(self, grammar: grammars.Grammar):
 
     def walk_Rule(self, rule: grammars.Rule):
         def param_repr(p):
-            if isinstance(p, int | float):
+            if isinstance(p, (int, float)):
                 return str(p)
             else:
                 return repr(p.split('::')[0])
diff --git a/tatsu/objectmodel.py b/tatsu/objectmodel.py
index 7c8fad2..7e4a786 100644
--- a/tatsu/objectmodel.py
+++ b/tatsu/objectmodel.py
@@ -112,7 +112,7 @@ def with_parent(node):
             return node
 
         def children_of(child):
-            if isinstance(child, weakref.ReferenceType | weakref.ProxyType):
+            if isinstance(child, (weakref.ReferenceType, weakref.ProxyType)):
                 return
             elif isinstance(child, Node):
                 yield with_parent(child)
@@ -121,7 +121,7 @@ def children_of(child):
                     if name.startswith('_'):
                         continue
                     yield from children_of(value)
-            elif isinstance(child, list | tuple):
+            elif isinstance(child, (list, tuple)):
                 yield from (
                     with_parent(c) for c in child if isinstance(c, Node)
                 )
diff --git a/tatsu/parser.py b/tatsu/parser.py
index 0e25fe5..c598b29 100644
--- a/tatsu/parser.py
+++ b/tatsu/parser.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import re
 from typing import Any
 
diff --git a/tatsu/synth.py b/tatsu/synth.py
index 9784100..3890f53 100644
--- a/tatsu/synth.py
+++ b/tatsu/synth.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from collections.abc import Mapping
 from typing import Any
 
diff --git a/tatsu/util/_common.py b/tatsu/util/_common.py
index 48c1503..14f5149 100644
--- a/tatsu/util/_common.py
+++ b/tatsu/util/_common.py
@@ -183,7 +183,7 @@ def decode_match(match):
 
 def isiter(value):
     return isinstance(value, Iterable) and not isinstance(
-        value, str | bytes | bytearray,
+        value, (str, bytes, bytearray),
     )
 
 
@@ -238,7 +238,7 @@ def timestamp():
 
 
 def asjson(obj, seen=None):  # noqa: PLR0911, PLR0912
-    if obj is None or isinstance(obj, int | float | str | bool):
+    if obj is None or isinstance(obj, (int, float, str, bool)):
         return obj
 
     if seen is None:
@@ -246,11 +246,11 @@ def asjson(obj, seen=None):  # noqa: PLR0911, PLR0912
     elif id(obj) in seen:
         return f'{type(obj).__name__}@{id(obj)}'
 
-    if isinstance(obj, Mapping | AsJSONMixin) or isiter(obj):
+    if isinstance(obj, (Mapping, AsJSONMixin)) or isiter(obj):
         seen.add(id(obj))
 
     try:
-        if isinstance(obj, weakref.ReferenceType | weakref.ProxyType):
+        if isinstance(obj, (weakref.ReferenceType, weakref.ProxyType)):
             return f'{obj.__class__.__name__}@0x{hex(id(obj)).upper()[2:]}'
         elif hasattr(obj, '__json__'):
             return obj.__json__(seen=seen)
@@ -301,7 +301,7 @@ def plainjson(obj):
             for name, value in obj.items()
             if name not in {'__class__', 'parseinfo'}
         }
-    elif isinstance(obj, weakref.ReferenceType | weakref.ProxyType):
+    elif isinstance(obj, (weakref.ReferenceType, weakref.ProxyType)):
         return '@ref'
     elif isinstance(obj, str) and obj.startswith('@'):
         return '@ref'
diff --git a/tatsu/util/misc.py b/tatsu/util/misc.py
index 8fc2b42..17fd4e2 100644
--- a/tatsu/util/misc.py
+++ b/tatsu/util/misc.py
@@ -1,10 +1,16 @@
 from __future__ import annotations
 
 import re
+import sys
 from collections.abc import Iterable
-from functools import cache
 from typing import TypeVar
 
+if sys.version_info > (3, 9):
+    from functools import cache
+else:
+    from functools import lru_cache
+    cache = lru_cache(None)
+
 _T = TypeVar('_T')
 
 _undefined = object()  # unique object for when None is not a good default
@@ -114,4 +120,4 @@ def with_incoming() -> set[_T]:
 def cached_re_compile(regex: re.Pattern | str | bytes) -> re.Pattern | None:
     if isinstance(regex, re.Pattern):
         return regex
-    return re.compile(regex) if isinstance(regex, (str | bytes)) else None
+    return re.compile(regex) if isinstance(regex, (str, bytes)) else None
diff --git a/tatsu/walkers.py b/tatsu/walkers.py
index 7762a4d..ed78d23 100644
--- a/tatsu/walkers.py
+++ b/tatsu/walkers.py
@@ -25,7 +25,7 @@ def __init__(self):
         )._walker_cache  # pylint: disable=no-member
 
     def walk(self, node: Node | list[Node], *args, **kwargs) -> Any:
-        if isinstance(node, list | tuple):
+        if isinstance(node, (list, tuple)):
             return [self.walk(n, *args, **kwargs) for n in node]
 
         if isinstance(node, Mapping):
diff --git a/test/grammar/semantics_test.py b/test/grammar/semantics_test.py
index 51deebd..4de537a 100644
--- a/test/grammar/semantics_test.py
+++ b/test/grammar/semantics_test.py
@@ -100,7 +100,7 @@ def test_builder_basetype_codegen(self):
         self.assertTrue(hasattr(ast, 'a'))
         self.assertTrue(hasattr(ast, 'b'))
 
-        self.assertTrue(issubclass(D, A | B | C))
+        self.assertTrue(issubclass(D, (A, B, C)))
 
     def test_optional_attributes(self):
         grammar = r"""