anchor.diff:  ")
   
   (defun spark (values &key (inf :min) (sup :max) key)
  -  "Generates a sparkline string for a list of the real numbers.
  +  "Generates a sparkline string for a list of real numbers.
   
   Usage: SPARK <values> &key <inf> <sup> <key>
   
  
positive.code: ;; (code-char 743) => #\MODIFIER_LETTER_MID_TONE_BAR              <=> #\˧
  ;; (code-char 746) => #\MODIFIER_LETTER_YANG_DEPARTING_TONE_MARK  <=> #\˫
  (defun generate-scale (inf sup size max-lengeth-label)
    (let* ((inf-string (princ-to-string (ensure-non-double-float inf)))
           (sup-string (princ-to-string (ensure-non-double-float sup)))
           (num-padding (- size
                           (length inf-string) (length sup-string))))
      (when (plusp num-padding)
        (let* ((mid (/ (+ sup inf) 2))
               (mid-string (princ-to-string (ensure-non-double-float mid))))
          (if (and (plusp (- num-padding (length mid-string)))
                   (/= inf mid)
                   (/= mid sup))
              (string-concat
               (if max-lengeth-label
                   (make-string (1+ max-lengeth-label) :initial-element #\Space)
                   "")
               (format nil (format nil "~~~D<~A~~;~A~~;~A~~>~~%"
                                   size inf-string mid-string sup-string))
               (if max-lengeth-label
                   (make-string (1+ max-lengeth-label) :initial-element #\Space)
                   "")
               (substitute #\- #\Space
                           (format nil (format nil "~~~D<~A~~;~A~~;~A~~>~~%"
                                               size #.(string (code-char 747))
                                               #\+ #.(string (code-char 743))))))
              (string-concat
               (if max-lengeth-label
                   (make-string (1+ max-lengeth-label) :initial-element #\Space)
                   "")
               inf-string
               (make-string num-padding :initial-element #\Space)
               sup-string
               #.(format nil "~%")
               (if max-lengeth-label
                   (make-string (1+ max-lengeth-label) :initial-element #\Space)
                   "")
               #.(string (code-char 747))
               (make-string (- size 2) :initial-element #\-)
               #.(string (code-char 743))
               #.(format nil "~%")))))))
  
  
  ;;====================================================================
  
negative.code:       (when (zerop unit) (setf unit 1))
  
        ;; (when *dbg*
        ;;   (format *debug-io* "~&sup: ~S~&inf: ~S~&unit: ~S~
        ;;                       ~%num-content-ticks: ~S~%size: ~S~%"
        ;;           sup inf unit num-content-ticks size))
  
        (loop
  