KeenWrite[0] is my desktop text editor that supports interpolated strings, R statements, and simple TeX expressions[1], all in real-time. The screenshot below shows a -π approximation found by tweaking inputs to the quadratic equation. An older video[2] shows some non-math scenarios.

Would appreciate reading your thoughts on integrated interpolated strings.

[0]: https://github.com/DaveJarvis/keenwrite

[1]: https://i.ibb.co/MSxVyHM/keenwrite-hn.png

[2]: https://www.youtube.com/watch?v=u_dFd6UhdV8