Emacs-style ranges on a text buffer that I can now hang attributes like color, decorations and click handlers on to. The final complexity cost was 200 lines but it was a non-linear path getting there. I went up to 500 lines before starting from scratch with a new approach. Earlier this year I threw out an implementation after suffering with it for 2+ years. It feels like I'm getting the hang of this programming thing that I threw out an implementation after 2 days.

Beautiful! I can very much appreciate the non linear effort that goes into such an editor. Can you also add an attribute that hides that part of the text, or that replaces it with another and still keep wrapping at the end of the visible line?

Not yet, no. But it's an interesting idea I hadn't considered. So far I only know how to conceal or replace text based on syntax rules.

I think mixing the two modes could be an interesting next step 🙂