LychenBASIC is not cutting-edge; not particularly modern in any way, shape or form; not platform-agnostic; not anything that will make you fall over yourself trying to download, compile and use.
However, as a platform on which to experiment with C#, it's okay. A previous posting, Action delegate gives Print to VBScript, refers to it, and it uses a technique discussed in another posting, Adding Assemblies on the fly in C# ClearScript projects.
Feel free to ignore it as much as you wish.
Meanwhile, I can now run scripts from within the REPL using
RUN "<name of script>" and I get meaningful error messages if it fails.