Creating functions that return news wire instances with incf'd function names

gistfile1.txt

(defclass counter-mixin ()
  ((counter :accessor counter :allocation :class :initarg :counter :type integer)))

(defmethod initialize-instance :after ((self counter-mixin) &key)
  (if (slot-boundp self 'counter)
      (incf (counter self))
      (setf (counter self) 0)))

(defclass wire (counter-mixin)
  ())

(defmacro make-new-wire ()
  (let* ((new-wire (make-instance 'wire))
	 (symbol-name (format nil "WIRE-~A" (counter new-wire))))
    `(defun ,(intern symbol-name) ()
       ,new-wire)))

=>

CL-USER> (make-new-wire)
WIRE-14
CL-USER> (wire-14)
#<WIRE @ #x10003da8d72>