Hi guys, I am helping my nephew for his C lab homework, it is a string manipulation assignment and applying Wang's algorithm.

Here is the BNF representation for the input.

<sequent> ::= <lhs> # <rhs>

<lhs> ::= <formulalist>| e
<rhs> ::= <formulalist>| e
<formulalist> ::= <formula>|<formula> , <formulalist>
<formula> ::= <letter>| - <formula>| (<formula><in?xop><formula>)
<in?xop> ::= & | | | >
<letter> ::= A | B | ... | Z

What is the best practice to handle and parse this kind of input in C? How can I parse this structure without using struct? Thanks in advance.