libre-rpn/lisp/list.lisp

(defun reduce (func list &optional init) ;; the use of init here is actually a bit broken wrt null
  (let* ((acc))
    (do* ((i (if init -1 0) (1+ i))
          (acc (if init init (elt list 0)) (func acc (elt list i))))
         ((>= i (1- (length list)))))
    acc))

(defun car (ls)
  (@ ls 0))

(defun cdr (ls)
  (chain ls (slice 1)))

(defun reverse (ls)
  (chain ls (reverse)))