anchor.diff:  
   
   
  +
  
positive.code: (format-errors 30000.15 '(314 3001)) => 30000(310)(3000){3020}
  (format-errors 30000.15 '(315 3001)) => 30000(320)(3000){3020}
  (format-errors 30000.15 '(315 3051)) => 30000(320)(3050){3070}
  ```" 
    (labels ((conc-detail (detail &optional only-last-no-digits)
  	     (with-slots (digits digits<one)
  		 detail
  	       (let+ ((has-separator (and
  				      (find *internal-separator-indicator* digits)
  				      only-last-no-digits
  				      (< (length digits<one) only-last-no-digits)))
  		      (digits-to-print
  		       (if only-last-no-digits
  			   (subseq digits (max 0 (- (length digits)
  						    (+ only-last-no-digits
  						       (if has-separator 1 0)))))
  			   digits)))
  		 (format nil "~{~a~}" (substitute *decimal-mark*
  						  *internal-separator-indicator*
  						  digits-to-print))))))
      (let+ ((sqrt-sum (sqrt-sum errors))
  	   (max-error-magn (reduce #'max (append (list sqrt-sum) errors)
  				   :key #'%get-order-of-magnitude))
  	   (.down-to (- max-error-magn default-error-digits))
  
negative.code: 
  (defun format-errors (value errors
  		      &key (stream nil) (default-error-digits 2))
   
    (labels ((conc-detail (detail &optional only-last-no-digits)
  	     (with-slots (digits digits<one)
  		 detail
  	       (let+ ((has-separator (and
  				      (find *internal-separator-indicator* digits)
  				      only-last-no-digits
  				      (< (length digits<one) only-last-no-digits)))
  		      (digits-to-print
  		       (if only-last-no-digits
  			   (subseq digits (max 0 (- (length digits)
  						    (+ only-last-no-digits
  						       (if has-separator 1 0)))))
  			   digits)))
  		 (format nil "~{~a~}" (substitute *decimal-mark*
  						  *internal-separator-indicator*
  						  digits-to-print))))))
        "Given a value in VALUE and a simple list of errors in ERRORS,
  FORMAT-ERRORS prints the value, list of errors, and the square root of
  the sum of the squares of the errors in delimiters (as defined by
  *ERROR-DELIMITERS* and *SUM-ERROR-DELIMITERS*) into STREAM (defaults
  