Nah, we've been doing this for years. At least ten years ago I built myself a little console based on Roslyn that would evaluate any C# snippets I gave it. C# scripts were pretty well supported, and it was not hard to throw one together. The engine of my console was a couple dozen lines mostly just processing the string.

I'm sure the tooling is better now, though. I seem to recall visual studio and/or Rider also supporting something like this natively at the time.