[danpetrov]

Emacs Lisp is totally usable as a minimal scripting language outside of the regular Emacs context.

You can compile Emacs without any GUI toolkit support and run it heedlessly as a lisp interpreter. You can even make Emacs packages behave like CLIs with a few lines of code.

[medo-bear]

of course. emacs itself is written in emacs lisp. it's not just an extension script for it. but it is not the most performant language. depending on the implementation, common lisp can be a beast with unmatched interactive development (in emacs of course)