Overview

The biggest problem with supporting multiple programming languages are the assumptions that CIDER has that it’s being used together with Clojure. In practice this translates to CIDER evaluating Clojure code in some cases to power its functionality. One simple example here would be switching the REPL’s namespace - CIDER simply evals in-ns behind the curtains to achieve this.

You also have to keep in mind that much of the advanced functionality (e.g. everything related to debugging) is not part of the core nREPL protocol and is provided by the cider-nrepl middleware. Other platforms will need to provide compatible implementation of that functionality, so that CIDER would work with.

Another problem is that some of the functionality is specific to Clojure and doesn’t make much sense in other languages, but that’s something that functionality can be simply ignored when non-applicable. There’s also some coupling with clojure-mode, but that’s not that hard to overcome. Some examples here would be the REPL (which uses clojure-mode syntax table and indentation rules), the logic for finding the current namespace (which uses clojure-find-ns), and so on. All such instances will need to be replaced eventually with more generic versions that dispatch on the type of the nREPL connection (e.g. Clojure, Racket, Fennel, etc).

Right now CIDER the supports to some extent the following:

All of them are derived from Clojure, so supporting them didn’t really require much work.

While not a very high priority, making CIDER usable with any nREPL server is certainly on the project’s roadmap. Here you can find a discussion about the changes needed to get CIDER to work with Fennel, plus a couple of commits that illustrate them.

Any help on that front would greatly appreciated!