I've made a GitHub repository with language support for newLISP in Visual Studio code: .
If you don't now VS Code have a look at , a very nice free editor, built on open source, from Microsoft, runs on Windows, Mac and Linux.
Current state of the extension is it does newLISP syntax highlighting, launching a newLISP REPL and evaluating the active file in the REPL. What I want to add is several color theme's and snippets (to show function syntax and explanations when 'hovering').
This is how it looks with theme Monokai:
Blue: the 'meta' functions (define, define-macro, macro, fn, lambda, lambda-macro)
Red: mutable primitive functions (set, push, ..)
Green: non-mutable primitive functions (list, array, append, ..)
Purple: numbers (integers, floats, bigints, ..)
Yellow: strings
Grey: quoted literals and comments
White: the rest
If you want to collaborate, need different colors or have ideas how to make this better, let me know!