anchor.diff:  unknown at the time it is created."
     (make-%promise-instance))
   
  -(defmethod %fulfill ((promise %promise) client-fn)
  +(defun fulfill-promise (promise client-fn)
     (with-%promise-slots (result lock cvar availablep) promise
       ;; spin until it is claimed
       (while availablep
  
positive.code: (defslots %chain ()
    ((object :reader chain-object)))
  
  ;;;; generics
  
  (defgeneric %fulfill (promise client-fn)
    (:method (object client-fn)
      (declare (ignore object client-fn))
      nil))
  
  (defgeneric %force (promise))
  
  ;;;; macros
  
  (defmacro with-lock-operation (operation promise &body body)
  
negative.code:       (fulfill-plan/values future (multiple-value-list (funcall client-fn))))
      t))
  
  (defun force-future (future)
    ;; If we are here then we've stolen the task from the kernel.
    (with-%future-slots (canceledp) future
      (setf canceledp t)
  