Interesting discussion of some of the subtleties which come up when writing code to display and manipulate text:

https://zed.dev/blog/zed-decoded-text-co...te-systems

Much of this echoes Finseth's classic book on implementing emacs-style editors, but with updates to reflect our Unicoded world.

(Many people will avoid dealing with these issues by simply dropping in whatever text widget their favorite library provides, but I enjoy cooking from scratch.)