what is to append as push is to cons, in Lisp?

Question

(push x list)

expands to

(setq list (cons x list))

What expands to the following:

(setq list (app         


        

Answer 1

Joshua Taylor mentioned how to do it in Common Lisp. I will answer how in Emacs Lisp:

(require 'cl-lib)
(defmacro appendf (place &rest lists)
  `(cl-callf append ,place ,@lists))
(defmacro prependf (list place)
  `(cl-callf2 append ,list ,place))

And some test:

(let ((to-prepend '(the good))
      (acc '(the bad))
      (to-append-1 '(the weird))
      (to-append-2 '(pew pew)))
  (prependf to-prepend acc)
  (appendf acc to-append-1 to-append-2)
  (list :acc acc
        :to-prepend to-prepend
        :to-append-1 to-append-1
        :to-append-2 to-append-2))
; ⇒ (:acc (the good the bad the weird pew pew) :to-prepend (the good) :to-append-1 (the weird) :to-append-2 (pew pew))

Macro expansion test:

(let ((print-gensym t))
  (print
   (macroexpand '(prependf y (cddr x)))))
; prints (let* ((#:a1 y) (#:v x)) (setcdr (cdr #:v) (append #:a1 (cddr #:v))))

For macroexpand-1 and pretty printing, use the macrostep package.