elisplisp.el

;; emacs-lisp-lisp (ell) demmo

(ell
  (setq mapcar
        (lambda (fn data)
          (print 'hi)
          (if (null data)
              nil
            (cons (fn (car data))
                  (mapcar fn (cdr data)))))))

(ell 
  (let ((plus3 (lambda (x) (+ x 3))))
    (print (mapcar plus3 (list 1 2 3))) ;; ell mapcar, will print 'hi 3 times before printing result
    (let ((mapcar '(native . mapcar)))
      (mapcar plus3 (list 4 5 6))))) ;; emacs lisp mapcar


;;output
hi

hi

hi

hi

(4 5 6)
(7 8 9)