(Triggering a heated discussion again...) Or maybe we can link Guile
to Emacs so that people can extend Emacs with the "GNU’s Ubiquitous
Intelligent Language for Extensions".
If the maintainers of Guile actually dropped their opposition to enforcing proper tail recursion at some point in the last 2 decades (when I last looked at it), then that's an option. The doc for v3 says proper tail recursion is supported, but then the section on history discusses the "proposed" support for proper tail recursion, so I don't really know what the status is.
Lynn