> This same phenomenon is the reason why John Ousterhout wrote Tcl and the GNU project started Guile. Except that Guile is an implementation of Scheme, which i

> This same phenomenon is the reason why John Ousterhout wrote Tcl and the GNU project started Guile. Except that Guile is an implementation of Scheme, which is essentially a somewhat minimalist variant of Lisp. So in this case, a real programming language was included intentionally as configuration language. And this is the same concept as why GNU Emacs is an editor written in Lisp on top of C routines - very similar how data science is often done in Python on top of Numpy and several other packages.