anchor.diff:      (maphash-values #'funcall callbacks)))
   
   (defparameter *ticks-per-second* 5)
  -(defvar *es-thread* nil)
  +(defvar *entity-system-thread* nil)
   (defun init-entity-system ()
  -  (setf *es-thread*
  +  (setf *entity-system-thread*
           (bt:make-thread (lambda ()
                             (loop with timer = (make-timer *ticks-per-second*)
                                do (timer-tick timer)
  
positive.code:    (ns :col-type text :initarg :ns)
     (name :col-type text :initarg :name)
     (description :col-type (or db-null text) :initarg :description)
     (numeric-value :col-type (or db-null numeric) :initarg :numeric-value)
     (text-value :col-type (or db-null text) :initarg :text-value))
    (:keys id))
  
negative.code:                     new-value (find-entity-by-uid new-value)))
              (t
               (add-modifier entity "entity" "uid" new-value
                             :description "Unique external identifier for entity."))))))
  
  (defun find-entity-by-uid (uid)
    (with-db ()
  