[cyphar]

While I don't write Scheme, I believe it is Scheme -- one of the goals of the GNU project is to have every GNU tool be configurable with Scheme (which is why GNU has a Scheme implementation as opposed to a Common LISP implementation).

[the_why_of_y]

Not only does GNU have a Common Lisp implementation, in fact there are two:

GCL: https://www.gnu.org/software/gcl/

CLISP: http://clisp.org/

[cyphar]

I've installed CLISP before, why didn't I know it was a GNU project? Fair enough, I stand corrected. :D

[brians]

Well, they have GCL and CLisp too!