In BNF, the only way to indicate a list of an arbitrary number of elements is through recursion.
Automated tools can use those descriptions (I'll use the generic term, BNF, to refer to both variations) or a close approximation thereto to generate your parsing code for you.
一百在BNF范式编码的基础上，深入讨论了生僻汉字数字化处理问题。
The BNF is used to formalize the network access control rules.
在BNF表示法中，为了表示一串任意个数的元素，唯一的方法是通过递归来定义。
BNF description of syntax
