Make is_integer a type guard, move to typing

loopy/kernel/array.py

@@ -49,9 +49,8 @@
 from pytools.tag import Tag, Taggable
 
 from loopy.diagnostic import LoopyError
-from loopy.tools import is_integer
 from loopy.types import LoopyType
-from loopy.typing import ExpressionT, ShapeType, auto
+from loopy.typing import ExpressionT, ShapeType, auto, is_integer
 
 
 if TYPE_CHECKING:

loopy/target/c/codegen/expression.py

@@ -46,10 +46,9 @@
 from loopy.expression import dtype_to_type_context
 from loopy.symbolic import TypeCast
 from loopy.target.c import CExpression
-from loopy.tools import is_integer
 from loopy.type_inference import TypeReader
 from loopy.types import LoopyType
-from loopy.typing import ExpressionT
+from loopy.typing import ExpressionT, is_integer
 
 
 __doc__ = """

loopy/tools.py

@@ -48,10 +48,6 @@
 logger = logging.getLogger(__name__)
 
 
-def is_integer(obj):
-    return isinstance(obj, (int, np.integer))
-
-
 def update_persistent_hash(obj, key_hash, key_builder):
     """
     Custom hash computation function for use with

loopy/type_inference.py

@@ -42,13 +42,13 @@
     SubstitutionRuleMappingContext,
     parse_tagged_name,
 )
-from loopy.tools import is_integer
 from loopy.translation_unit import (
     CallablesInferenceContext,
     TranslationUnit,
     make_clbl_inf_ctx,
 )
 from loopy.types import NumpyType
+from loopy.typing import is_integer
 
 
 logger = logging.getLogger(__name__)

loopy/typing.py

@@ -34,7 +34,7 @@
 from typing import Optional, Tuple, TypeVar
 
 import numpy as np
-from typing_extensions import TypeAlias
+from typing_extensions import TypeAlias, TypeIs
 
 from pymbolic.primitives import Expression
 from pymbolic.typing import ExpressionT, IntegerT
@@ -61,6 +61,10 @@ def not_none(obj: Optional[T]) -> T:
     return obj
 
 
+def is_integer(obj: object) -> TypeIs[int | np.integer]:
+    return isinstance(obj, (int, np.integer))
+
+
 def integer_or_err(expr: ExpressionT) -> IntegerT:
     if isinstance(expr, (int, np.integer)):
         return expr