Revision history [back]

@Fetullah Atas' answer got me most of the way there. Moving my comment to an answer to hopefully improve visibility. As a potential correction to his example, using a secondary launch argument that references the first is one possible workaround.

Example:

joy_config = LaunchConfiguration('joy_config')
joy_config_dec= DeclareLaunchArgument('joy_config', default_value='ps3')
final_string_dec= DeclareLaunchArgument('final_string', default_value=[LaunchConfiguration('joy_config'), '.config.yaml'])

Which would result in LaunchConfiguration('final_string') evaluating to: "ps3.config.yaml".

I'd be surprised if there wasn't a more direct solution since this question was originally asked.