I really hope that Lisp will get a comeback in the space that is now occupied by XML and YAML. It's always the same story: Narrow minded engineers chose YAML (formerly XML) as the trendy simple configuration language and it works fine for a while. 3 years later they inevitably hit the ceiling with YAML and either start badly implementing new language features on top of YAML (see Gitlab CI's `when`, `only`, `except`, etc. syntax) that are never flexible enough or write hugely complicated templating tools (see Kustomize and Helm for K8S) for things that would amount to a simple if-expression in Lisp. This is the use case where Lisp can really shine. Configuration is almost always untyped and doesn't start out with a library ecosystem. Most of the time you just need a way to write a simple nestable DSL that is human readable. There's probably no language that makes this simpler than Lisp: Any college freshman could write their own interpreter. But it is also extremely flexible if it turns out that you need more power than YAML offers.