qemacs is a nice emacs style editor by Fabrice Bellard (qemu's original author).

qemacs is small enough so that it can be compiled as a 100kb executable, but also has a simple codebase that could be the base for experimentation.

This project is mostly a testbed to learn using an existing codebase.

Some goals would be:

• make a modern screen driver using eg. Qt in order to have a UI optimized for long coding sessions.
• Integrate an scripting language, like lua, for configuration and extensibility

https://github.com/dmacvicar/qemacs (see the qt5-single-loop branch)