anchor.diff:    "Mutex lock for accessing `%DOMAINS%'")
   
   
  -;;; %% Access Functions
  +;;; %%% Access Functions
   
   (defun register-measurement-class (c)
     (declare (type measurement-class c))
  
positive.code: (defgeneric measurement-symbol (instance))
  
  
  (defclass* (measurement-class 
  	    :conc-name #:measurement-)
      ;; FIXME: Remove?
      (standard-class pretty-printable-object)
    ((symbol symbol  :read-only t)))
  
  
negative.code:              (entity-not-found-name c)))))
  
  
  ;;; %% Measurement Class Storage and Access
  
  ;;; %%% Locking (Thread Safety)
  
  (declaim (type (vector measurement-class) %measurement-classes% ))
  
  