In my CC Mode development, I have to maintain fairly large regexps. I'd like to use better tools than `regexp-opt' and `concat' to do that. In Emacs there are two packages to aid in building regexps using an sexp syntax: sregexp.el and rx.el. I've looked around for similar regexp building packages in XEmacs but haven't found any. So my first question is: Are there such tools distributed with XEmacs? If not, I suggest that sregexp.el and rx.el are added to XEmacs, so that they can be used in code that needs to be compatible with both Emacs and XEmacs. Both Emacs packages solve the same problem. rx.el is a bit newer and exploits shy groups while sregexp.el provide tools to keep track of submatch groups. If there has to be a choice, I'd prefer sregexp.el simply because it's older and works with Emacs 20 which I want to remain compatible with. My second question is: Would it be ok to add these two to a package that can be trusted to be installed?