(while (> n 0)
        (unless (re-search-forward
                 "\\(\\=\\|[^\\\\]\\)\\(\\\\\\\\\\)*\\([{}]\\)" nil t)
          (debug))
        (message "N0.3")
        (if (string= (match-string 3) "{")
            (setq i (1+ i))
          (message "N0.4")
          (setq i (1- i))
          (message "N0.5 %s" i)
          (when (<= i 0)
            (message "N0.5.1")
            (setq n (1- n))
            (message "N0.2"))))
          (message "N0.6")
      (message "N1.1")
      (setq result (buffer-substring-no-properties point (point)))


gives
N0.3
N0.4
N0.5 1
Not enough arguments for format string