Python style range implementation in lisp

range.lisp

(defun range(s &optional end step_)
  (let
   (
     (start (cond
              (end s)
              (T 0)))
     (end   (cond
              (end end)
              (T s)))
     (step_  (cond
              (step_ step_)
              (T 1)))
     (result (list nil))
   )
   (loop
     (push start (cdr (last result)))
     (setq start (+ start step_))
     (when
        (or
         (and (> step_ 0) (>= start end))
         (and (< step_ 0) (<= start end)))
        (return (cdr result))
     )
   )
  )
)

Which one could write as

(defun range (s &optional end (step 1))
  (if (null end)
      (loop for i below s by step collect i)
    (loop for i from s below end by step collect i)))

or

(defun range (s &optional end (step 1))
  (loop for i from (if end s 0) below (if end end s) by step
        collect i))

or even

(defun range (s &optional (end s end-passed) (step 1))
  (loop for i from (if end-passed s 0) below end by step
        collect i))