I wonder how hard it would be to use this with Unity? Getting a REPL into a running game is the biggest reason I'm interested in Lisp in games, but engine options are limited (the one I've tried is LOVE with Fennel, but Fennel is a bit odd as a Lisp and doesn't actually give you a REPL into a live program without extra work, and LOVE gives a lot less engine-stuff than Unity).

Seconding this. Arcadia is a breeze to get running.

Just downloaded Unity to quickly check that it's possible, which ended up being pretty easy to enable.

I've documented how to add Lisp scripting to an existing project at:

https://sharpscript.net/lisp/unity

Here's a youtube demo of scripting game objects at runtime with an in-game REPL at:

https://www.youtube.com/watch?v=WmzI-5L0hJk

Never tried, but it's available in .NET Standard 2.0 + .NET v4.5 builds which has run everywhere I've tried that supports either of those target frameworks, e.g. have also been able to add scripting to an Xamarin.Android App.

Have been trying to understand the coolness of this language for a long time, but never seem to connect with it. This is by far the most practical-looking example of LISP I have ever seen.

Have you ever tried Clojure? It is an extremely pragmatic language for building APIs and web apps.

See also Schemy [1].

[1] https://github.com/microsoft/schemy

Not to be confused with SCE-MI [1].

[1] https://accellera.org/downloads/standards/sce-mi