I occasionally get grief because Axiom is implemented in Common Lisp. People don't seem to like that for some odd reason. Lisp, one of the easiest languages to learn, seems to be difficult to accept.
I'm working with John Harrison's book "Practical Logic and Automated Reasoning" from 2009. It uses OCaml to implement the programs. I've downloaded the OCaml sources from the website. Apparently OCaml has changed significantly from 2009 since the code no longer compiles, spitting out "Alert deprecated" all over the place and simply failing in places. C++ code has a "standard", well, several "standards". When someone asks "Do you know C++" you really need to qualify that question. What you knew about "standard C++" seems to change every 2 years. I recently pulled out my KROPS code, used as the basis for IBM's Expert System FAME. It was written in Common Lisp (on a Symbolics machine). It still runs unmodified despite being written about 40 years ago on hardware and a software stack that no longer exists. Axiom, written in the last century, still compiles and runs. Say what you want about Lisp code, it still is the most portable and long-lasting language I've ever used. Tim