(defun select (selector-fn)

  (remove-if-not selector-fn *db*))

 

(defun where (&key title artist rating (ripped nil ripped-p))

  #'(lambda (cd)

    (and

      (if title    (equal (getf cd :title)  title)  t)  

      (if artist   (equal (getf cd :artist) artist) t)

      (if rating   (equal (getf cd :rating) rating) t)

      (if ripped-p (equal (getf cd :ripped) ripped) t))))