anchor.diff:      :documentation "The time-base used by this scheduler."))
     (:documentation "The base class for schedulers."))
   
  +
   (defgeneric print-scheduler-activities (scheduler &optional stream))
   (defgeneric scheduler-all-activities (scheduler))
   (defgeneric schedule-activity   (scheduler activity))
  
positive.code: (defgeneric time-scheduler-idle-activities (scheduler))
  
  (defmethod time-scheduler-idle-activities ((scheduler time-scheduler))
    (scheduler-activities (time-scheduler-idle-scheduler scheduler)))
  
  (defmethod scheduler-all-activities ((scheduler time-scheduler))
    (append (time-scheduler-idle-activities scheduler)
            (copy-list (scheduler-activities scheduler))))
  
  (defmethod schedule-activity ((scheduler time-scheduler) (activity activity))
    "
  
negative.code:         (line-cs
           (let ((precision      (precision (scheduler-time-base scheduler)))
                 (all-activities (scheduler-all-activities scheduler)))
             (print (list 'all-activities all-activities)) (finish-output)
             (format nil "~~&~~4D ~~8A ~A ~A ~~:[.~~;D~~]~~:[.~~;E~~] ~~S~~%"
                     (format-for-field all-activities
                                       (function activity-scheduled-time)
  