My Lisp education was mostly from Elisp, but this I understood early when I was reading some random code and came across:
(setf (buffer-string) "hello")
I thought this was just bananas, turns out that Elisp setf simply has a bunch of hardcoded rules for matching getters/setters for even a lot of non-standard data structures like Buffer that are Emacs specific. So the above gets rewritten to:
Unfortunately, it is marked obsolete since 29.1. The NEWS says:
* Many seldom-used generalized variables have been made obsolete.
Emacs has a number of rather obscure generalized variables defined,
that, for instance, allowed you to say things like:
(setf (point-min) 4)
These never caught on and have been made obsolete. The form above,
for instance, is the same as saying
