# Copyright 2018 Open Source Robotics Foundation, Inc.
#
# 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.
"""Module for the LocalSubstitution substitution."""
from typing import Optional
from typing import Text
from ..launch_context import LaunchContext
from ..substitution import Substitution
from ..utilities import ensure_argument_type
[docs]
class LocalSubstitution(Substitution):
"""Substitution that can access contextual local variables."""
[docs]
def __init__(self, expression: Text, description: Optional[Text] = None) -> None:
"""Create a LocalSubstitution."""
super().__init__()
ensure_argument_type(expression, str, 'expression', 'LocalSubstitution')
self.__expression = expression
self.__description = description
@property
def expression(self) -> Text:
"""Getter for expression."""
return self.__expression
@property
def description(self) -> Optional[Text]:
"""Getter for description."""
return self.__description
[docs]
def describe(self) -> Text:
"""Return a description of this substitution as a string."""
msg = self.expression if self.description is None else self.description
return "LocalVar('{}')".format(msg)