(defun BalancedBrackets (str / cntOpen curr)
  (setq cntOpen 0)
  (setq str (vl-string->list str))
  (while (and (>= cntOpen 0) str)
    (setq curr (car str) str (cdr str))
    (cond
      ((= 91 curr) (setq cntOpen (1+ cntOpen)))
      ((= 93 curr) (setq cntOpen (1- cntOpen)))
    )
  )
  (and (null str) (zerop cntOpen))
)