(progn
  (defun add (a b) (+ a b))
  (defvar whatever 16))

;; struct
(progn 
  (defun constructor-name (sym)
    (intern (concatenate 'string "MAKE-" (string sym))))

  (defun accessor-name (name sym)
    (intern (concatenate 'string (string name) "-" (string sym))))

  (defun setter-name (name sym)
    (intern (concatenate 'string "SET-" (string name) "-" (string sym))))

  (defmacro mydefstruct (name &rest slots)
    `(progn
       (defun ,(constructor-name name)
	 ,slots
	 (list ,@slots))
       ,@(loop for i from 0 to (1- (length slots)) collect
	       `(defun ,(accessor-name name (nth i slots))
		    (instance)
		  (nth ,i instance)))
       ,@ (loop for i from 0 to (1- (length slots)) collect
		`(defun ,(setter-name name (nth i slots))
		     (instance val)
		   (setf (nth ,i instance) val)))
       ,@(loop for i from 0 to (1- (length slots)) collect
	       `(defsetf ,(accessor-name name (nth i slots))
		    ,(setter-name name (nth i slots)))))))