Add TextJoinSubstitution

launch/launch/substitutions/__init__.py

@@ -33,6 +33,7 @@
 from .path_join_substitution import PathJoinSubstitution
 from .python_expression import PythonExpression
 from .substitution_failure import SubstitutionFailure
+from .text_join_substitution import TextJoinSubstitution
 from .text_substitution import TextSubstitution
 from .this_launch_file import ThisLaunchFile
 from .this_launch_file_dir import ThisLaunchFileDir
@@ -57,6 +58,7 @@
     'PathJoinSubstitution',
     'PythonExpression',
     'SubstitutionFailure',
+    'TextJoinSubstitution',
     'TextSubstitution',
     'ThisLaunchFile',
     'ThisLaunchFileDir',

launch/launch/substitutions/text_join_substitution.py

@@ -0,0 +1,56 @@
+# Copyright 2024 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 TextJoinSubstitution substitution."""
+
+from typing import Iterable
+from typing import Text
+from typing import Union
+
+from ..launch_context import LaunchContext
+from ..substitution import Substitution
+
+
+class TextJoinSubstitution(Substitution):
+    """Substitution that join texts using a separator."""
+
+    def __init__(
+        self, substitutions: Iterable[Union[Text, Substitution]], separator: Text = ""
+    ) -> None:
+        """Create a TextJoinSubstitution."""
+        from ..utilities import normalize_to_list_of_substitutions
+
+        self.__substitutions = normalize_to_list_of_substitutions(substitutions)
+        self.__separator = separator
+
+    @property
+    def substitutions(self) -> Iterable[Substitution]:
+        """Getter for variable_name."""
+        return self.__substitutions
+
+    @property
+    def separator(self) -> Text:
+        """Getter for separator."""
+        return self.__separator
+
+    def describe(self) -> Text:
+        """Return a description of this substitution as a string."""
+        return "LocalVar('{}')".format(
+            " + ".join([s.describe() for s in self.substitutions])
+        )
+
+    def perform(self, context: LaunchContext) -> Text:
+        """Perform the substitution by joining the texts."""
+        performed_substitutions = [sub.perform(context) for sub in self.__substitutions]
+        return self.__separator.join(performed_substitutions)

launch/test/launch/substitutions/test_text_join_substitution.py

@@ -0,0 +1,29 @@
+# Copyright 2024 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.
+
+"""Tests for the TextJoinSubstitution substitution class."""
+
+from launch.substitutions import TextJoinSubstitution
+
+
+def test_text_join_default():
+    texts = ["ab", "cde", "f"]
+    sub = TextJoinSubstitution(texts)
+    assert sub.perform(None) == "abcdef"
+
+
+def test_text_join():
+    texts = ["ab", "cde", "f"]
+    sub = TextJoinSubstitution(texts, separator=".")
+    assert sub.perform(None) == "ab.cde.f"