The smach_ros package contains extensions for the SMACH library to integrate it tightly with ROS. For example, SMACH-ROS can call ROS services, listen to ROS topics, and integrate with<a href="http://www.ros.org/wiki/actionlib">actionlib</a>both as a client, and a provider of action servers. SMACH is a new library that takes advantage of very old concepts in order to quickly create robust robot behavior with maintainable and modular code.