Yeah, I always write the grammar before writing the recursive descent parser. I can't imagine doing otherwise. It would be a mess. I'd go further and say tha

Yeah, I always write the grammar before writing the recursive descent parser. I can't imagine doing otherwise. It would be a mess. I'd go further and say that for most people, the first time you read or write a context-free grammar is when you're trying to write a parser. So the theory is motivating the practice.