[Waterluvian]

In ROS we have these XML launch files that are just awful. They have enough features to be a really bad programming language for configuring and launching (often conditionally) numerous robot software nodes.

In ROS2 the launchfile can now just be a Python script. Very much learned all this the hard way and the solution was to just support Python. I think it's brilliant.

[pjmlp]

AOLServer and our own Tcl based application server also used this idea.

Configuration files for each component were a DSL made of Tcl functions. Each module just sourced the respective file on load.