Подсчитать сумму всех четных и нечетных элементов списка

(defun sum-sum (x mode)
   (cond ((= mode 'ODD)
          (prog (s i)
            (setq i 1)
            (setq s 0)
            (return (dolist (a x s) (if (= (mod i 2) 1) (setq s (+ a s))) (setq i (+ i 1) )))
          ))
         ((= mode 'EVEN)
          (prog (s i)
            (setq i 1)
            (setq s 0)
            (return (dolist (a x s) (if (= (mod i 2) 0) (setq s (+ a s))) (setq i (+ i 1) )))
          )) 
         (t 'Bad_mode!)))
 
==> sum-sum
 
(sum-sum '(1 2 3 4 5 6) 'even)
 
==> 12
 
(sum-sum '(1 2 3 4 5 6) 'odd)
 
==> 9

(defun get-even (x)
   (cond ((null (cdr x)) nil)
         (t (cons (cadr x) (get-even (cddr x))))))
 
==> get-even
 
(get-even '(1 2 3 4 5 6))
 
==> (2 4 6)
 
(defun get-odd (x)
   (cond ((null (cdr x)) nil)
         (t (cons (car x) (get-odd (cddr x))))))
 
==> get-odd
 
(get-odd '(1 2 3 4 5 6))
 
==> (1 3 5)
 
(defun sum-sum-f (x filtr)
   (apply '+ (funcall filtr x)))
   
==> sum-sum-f
 
(sum-sum-f '(1 2 3 4 5 6) #'get-odd)
 
==> 9
 
(sum-sum-f '(1 2 3 4 5 6) #'get-even)
 
==> 12

(defun sum-evens (list)
  (loop
       for even = nil then (not even)
       for item in list when even sum item))
 
(defun sum-odds (list)
  (loop
       for odd = t then (not odd)
       for item in list when odd sum item))

(defun sum-evens (list)
  (iter (for i in (cdr list) by #'cddr)
        (summing i)))
 
(defun sum-odds (list)
  (iter (for i in list by #'cddr)
        (summing i)))

(defun sum-odd (w &optional (ac 0)) 
  (cond ((null w) ac)
        ((oddp (car w)) (sum-odd (cdr w) (+ ac (car w))))
        ((sum-odd (cdr w) ac))))
 
> (sum-odd '(1 2 3 4))
4

(defun sum-even (w &optional (ac 0)) 
  (cond ((null w) ac)
        ((evenp (car w)) (sum-even (cdr w) (+ ac (car w))))
        ((sum-even (cdr w) ac))))
 
> (sum-even '(1 2 3 4))
6