> Most HLLs today wrap an existing C regular expression library, and I don't know any C regular expression library that provides a public interface to its parse tree, so it's unlikely that other languages will be able to do something similar without a lot of work.

I don't think I know of one either. But Go's regexp library provides access to the syntax[1], and so does rust/regex[2]. In the case of [2], it provides both an AST and a high level IR for regexes. It's not as convenience to build expressions as in your Lisp example, though, there's nothing stopping someone from building such a convenience. :-)

[1] https://golang.org/pkg/regexp/syntax/

[2] https://docs.rs/regex-syntax