Post Syndicated from jake original https://lwn.net/Articles/951090/

Lisp
is one of the oldest programming languages still in use today, but it has
evolved in multiple directions over its more than 60-year history. Two of
the more prominent descendants, Common Lisp and Emacs Lisp (or Elisp),
are fairly closely related at some level, but there is still something of a
divide between them. Some recent discussion in the emacs-devel mailing
list have shown that some elements from Common Lisp are not completely
welcome in
Elisp—at least in the code that is maintained by the Emacs project itself.