Extensions to highlight different parts of regex

Are there any extensions knowing what functions and where accept regex and highlighting regex syntax?

We need to catch up with neovim on this one https://github.com/bennypowers/nvim-regexplainer

I don't understand what you're asking. But if you're asking about libraries that highlight matches of different parts (e.g. groups) of regexp matches differently (e.g. different colors), then both [Isearch+](https://www.emacswiki.org/emacs/IsearchPlus) and [Icicles](https://www.emacswiki.org/emacs/Icicles) do that. [With isearch](https://www.emacswiki.org/emacs/IsearchPlus#RegexpGroupHighlighting) and [with Icicles search](https://www.emacswiki.org/emacs/Icicles_-_Search_Commands%2c_Overview#SearchHighlightingContextLevels).

see: https://github.com/joddie/pcre2el and: https://github.com/mattiase/xr

I personnaly use [visual-regexp-on-steroids](https://github.com/emacsmirror/visual-regexp-steroids)

It's not what I am looking for but anyway thanks as suggested plugins are seems to be useful for me. :) I want regex strings in ELisp source code for instance to be colorized.

Depending on you use case, this might be interesting for you as well. [https://github.com/alk/elisp-regex-dsl](https://github.com/alk/elisp-regex-dsl) That's what I use in my elisp code.

This is an excellent package, I always recommend it to my colleagues

Neato! Imagine something like regex101-at-point. Their explainer is awesome.