;; lp.l - lisp processes

(defun filter (predicate list)
  (cond
    ((null list)
      ()
    )
    ((funcall predicate (car list))
      (cons (car list) (filter predicate (cdr list)))
    )
    (t
      (filter predicate (cdr list))
    )
  )
)

(defun pick (list)
  (cond
    ((null list)
      NIL
    )
    (t
      (nth (random (length list)) list)
    )
  )
)