Hello there,
It seems that you are working on a compiler designing assignment. Recently I have completed two assignments on compiler design using flex, bison, and C on Ubuntu platform. From the job description, it seems that you want to build a recursive descent parser from the parser that you already have. I would like to take a look at the details of the task you want to perform in order to see if I can help you in your assignment.
Feel free to contact me if you find this proposal useful.
Regards,
Atul Rajdhar