# Copyright 2017 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.

# ==============================================================================

"""Utility to retrieve function args.."""

from __future__ import absolute_import

from __future__ import division

from __future__ import print_function

from tensorflow.python.util import tf_decorator

from tensorflow.python.util import tf_inspect

def fn_args(fn):

"""Get argument names for function-like object.

Args:

fn: Function, or function-like object (e.g., result of `functools.partial`).

Returns:

`tuple` of string argument names.

Raises:

ValueError: if partial function has positionally bound arguments

"""

_, fn = tf_decorator.unwrap(fn)

# Handle callables.

if hasattr(fn, '__call__') and tf_inspect.ismethod(fn.__call__):

return tuple(tf_inspect.getargspec(fn.__call__).args)

# Handle functools.partial and similar objects.

if hasattr(fn, 'func') and hasattr(fn, 'keywords') and hasattr(fn, 'args'):

# Handle nested partial.

original_args = fn_args(fn.func)

if not original_args:

return tuple()

return tuple([

arg for arg in original_args[len(fn.args):]

if arg not in set((fn.keywords or {}).keys())

])

# Handle function.

return tuple(tf_inspect.getargspec(fn).args)