Create a base types module and populate it with the Tensor base class, along with its Graph and Eager subclasses.

PiperOrigin-RevId: 302925149
Change-Id: I1e652d938f2a346d37759de5be9dca5623a7500b

tensorflow/python/BUILD

@@ -1864,6 +1864,7 @@ py_library(
         ":tensor_shape",
         ":util",
         "//tensorflow/core:protos_all_py",
+        "//tensorflow/python/types",
     ],
 )
 

tensorflow/python/framework/tensor_util.py

@@ -27,6 +27,7 @@ from tensorflow.python.framework import dtypes
 from tensorflow.python.framework import ops
 from tensorflow.python.framework import tensor_like
 from tensorflow.python.framework import tensor_shape
+from tensorflow.python.types import core
 from tensorflow.python.util import compat
 from tensorflow.python.util import nest
 from tensorflow.python.util.tf_export import tf_export
@@ -995,7 +996,8 @@ def is_tensor(x):  # pylint: disable=invalid-name
   Returns:
     `True` if `x` is a tensor or "tensor-like", `False` if not.
   """
-  return (isinstance(x, tensor_like._TensorLike) or  # pylint: disable=protected-access
+  # TODO(mdan): Remove these. Only keep core.Tensor.
+  return (isinstance(x, (tensor_like._TensorLike, core.Tensor)) or  # pylint: disable=protected-access
           ops.is_dense_tensor_like(x) or
           getattr(x, "is_tensor_like", False))
 

tensorflow/python/types/BUILD

@@ -0,0 +1,31 @@
+load("//tensorflow:tensorflow.bzl", "py_strict_library")
+
+package(
+    licenses = ["notice"],  # Apache 2.0
+)
+
+filegroup(
+    name = "all_files",
+    srcs = glob(
+        ["**/*"],
+        exclude = [
+            "**/METADATA",
+            "**/OWNERS",
+        ],
+    ),
+    visibility = ["//tensorflow:__subpackages__"],
+)
+
+# Important: this is a leaf library. It may not have any new dependencies inside TF proper.
+# The sole exception is tf_export, to allow exporting symbols into the public namespace.
+py_strict_library(
+    name = "types",
+    srcs = [
+        "__init__.py",
+        "core.py",
+    ],
+    srcs_version = "PY2AND3",
+    visibility = ["//tensorflow:__subpackages__"],
+    deps = [
+    ],
+)

tensorflow/python/types/__init__.py

@@ -0,0 +1,25 @@
+# Copyright 2016 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Public TensorFlow type definitions.
+
+For details, see
+https://github.com/tensorflow/community/blob/master/rfcs/20200211-tf-types.md.
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+# Note: this module should contain **type definitions only**.

tensorflow/python/types/core.py

@@ -0,0 +1,60 @@
+# Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Core TensorFlow types."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+
+# TODO(mdan): Consider adding ABC once the dependence on isinstance is reduced.
+# TODO(mdan): Add type annotations.
+
+
+class Tensor(object):
+  """The base class of all dense Tensor objects.
+
+  A dense tensor has a static data type (dtype), and may have a static rank and
+  shape. Tensor objects are immutable. Mutable objects may be backed by a Tensor
+  which holds the unique handle that identifies the mutable object.
+  """
+
+  @property
+  def dtype(self):
+    pass
+
+  @property
+  def shape(self):
+    pass
+
+
+class Symbol(Tensor):
+  """Symbolic "graph" Tensor.
+
+  These objects represent the output of an op definition and do not carry a
+  value.
+  """
+  pass
+
+
+class Value(Tensor):
+  """Tensor that can be associated with a value (aka "eager tensor").
+
+  These objects represent the (usually future) output of executing an op
+  immediately.
+  """
+
+  def numpy(self):
+    pass