Write a plugin/class that can be used for a code editor

I want a RealBasic plugin or a class that can do the basic things a code editor can: -Syntax highlighting -Code completion -Line numbers It must be OOP, and customizable so maybe in the future there can functions be added, for example: -Code folding -... It would be nice if code completion and syntax highlighting works via XML files, so the code completion can be changed any time. I think something like VS does, would be nice. I added a picture of that.