prism.el VS borg

Heh, seriously, though, it's not necessary to use a rainbow of colors. You can use any number of colors and rotate through them. For example, this uses just 3 colors, gradually desaturating them as the depth increases. Since each color is easily distinguished from the other 2, it makes code very readable: https://github.com/alphapapa/prism.el/raw/master/images/parens-0.5.png

If you can use tree-sitter, that's obviously a good choice. Alternatively, you can see how I implemented https://github.com/alphapapa/prism.el, which isn't regexp-based, using Emacs's built-in syntax parsing instead.

I did some experimenting with supporting XML directly in https://github.com/alphapapa/prism.el/issues/16. It seems that it's not easily done with existing Emacs SGML-related functions, but I'm guessing that tree-sitter will help a lot in Emacs 29.

It's not exactly what you asked for, but you may also find this useful: https://github.com/alphapapa/prism.el It can highlight parens distinctly too.

As examples, I can recommend code in https://github.com/alphapapa/highlight-function-calls (simple) and https://github.com/alphapapa/prism.el (more complex).

There is also the package prism.el.

The best advice I can offer is to carefully and repeatedly study the Elisp manual section on font-lock, and to model on the source code of a similar project. The most I've done with it is in https://github.com/alphapapa/prism.el

There is one for emacs. Could be good inspo if someone wanted to make a VSCode version.

https://github.com/alphapapa/prism.el

You might be interested in https://github.com/alphapapa/prism.el

I use a combination of package.el and borg

borg is a bare-bones package manager that installs packages using Git submodules. It is most useful to package authors and users who also contribute to the packages that they use.