Lisp in the middle: using Lisp to manage a Linux system

In the Lisp community one can still find some nostalgia for the time of Lisp machines. The defining feature that has been since lost is having a powerful programming language as the main method of controlling the system behaviour.

Unfortunately, to the best of our knowledge, there are few modern systems that try to revive this approach. Moreover, regardless of the configuration language in use, managing the  system as a whole is usually associated purely with managing a global persistent state, possibly with parts of it getting enabled or disabled in runtime.

We present a system design and a description of a partial implementation of Lisp-in-the-middle, a system based on the common GNU/Linux/X11 stack that uses Common Lisp for runtime system policy and per-user policy. We prioritise ease of achieving compatibility with niche workflows, low rate of purely maintenance changes, and minimising the unnecessary interactions between the parts of the system unless requested by user.