Emacs/Elisp has the rx library: https://www.gnu.org/software/emacs/manual/html_node/elisp/Rx...

You get s-exp-based regex syntax (example for C-style block comments; there are shorter aliases too, e.g. `zero-or-more` can be written as `*`):

    (rx "/*"                    ; Initial /*
        (zero-or-more
         (or (not "*")          ;  Either non-*,
             (seq "*"           ;  or * followed by
                  (not "/"))))  ;     non-/
        (one-or-more "*")       ; At least one star,
        "/")                    ; and the final /

and you have rx-define and rx-let to defined named subforms:

    (rx-let ((comma-separated (item) (seq item (0+ "," item)))
             (number (1+ digit))
             (numbers (comma-separated number)))
      (re-search-forward (rx "(" numbers ")")))

And this is just the regex builder - syntactic sugar - as it still just builds a single regex serialized to a normal string.

I tend to use it everywhere, since it is guaranteed to always properly escape all backslashes (a major pain point in string regexes in Emacs), but it's also useful for building larger regexes from chunks and reusing chunks in multiple related regexes.*