anchor.diff:              (k (parse-format-formatter fmtr))]
          (lambda (ref)
            (list 'urn-format ref (display-with-sep (string/sub sep 2 (- (n sep) 1)) (k 'ignored)))))]
  -    [(= spec "") (lambda (ref) (list 'urn-format ref `pretty))]))
  +    [(= spec "") (lambda (ref) (list 'urn-format ref `display))]))
   
   (defun handle-formatting-specifier (spec last-pos) :hidden
     "Parse the entirety of the format specifier SPEC."
  -  (let* [((ref spec) (parse-format-reference spec))
  +  (let* [((ref spec) (parse-format-reference spec last-pos))
            ((formatter spec) (parse-format-formatter spec))]
  -  (values-list (formatter ref) last-pos)))
  +  (formatter ref)))
   
   (defun parse-format (str) :hidden
     "Parse the format string STR into a list of fragments."
     (let* [(cur "") ; the current character (for convenience)
            (buf "") ; a buffer
  -         (last-positional 1) ; for anonymous positions
  +         ; we don't have pointers, so we keep it in a table.
  +         (last-positional { 1 1 }) ; for anonymous positions
            (frags '())]
       (loop [(i 1)]
         [(> i (n str))
  
positive.code:   (or (= c ":")
        (= c "%")))
  
  (defun parse-format-reference (str) :hidden
    "Parse the formatting reference STR."
    (let* [((val end)
            (cond
  
negative.code:            [(or (>= j (n str))
                  (= (string/char-at str j) "}"))
              (set! i j)
              (let* [(frag (handle-formatting-specifier parsed last-positional))]
                (push-cdr! frags frag))]
             (recur (.. parsed (string/char-at str j)) (+ 1 j)))]
          [else => (set! buf (.. buf it))])
  