anchor.diff:  
   (defgeneric measurement-magnitude (instance))
   
  +;; FIXME: rename to measurement-scale
   (defgeneric measurement-degree (instance))
   
   
  
positive.code: 
  ;; (truncate (* 1.201 (expt 10 3)))
  
  
  
  ;; sidebar: sb-impl::make-float
  
  
  ;; / decimal-scale.lisp --------------------
  
negative.code:                               magnitude)))))
             (t (incf n)))))))
  
  ;; (float-shift-digits 1)
  ;; => 0, 1
  
  ;; (float-shift-digits 12)
  ;; => 0, 12
  ;; (float-shift-digits 12.0)
  