Nice! If you are interested by testing your library on a concrete problem, you may want to parse comma separated value (csv) files. The bnf is in the specification RFC4180. http://tools.ietf.org/html/rfc4180
AFAIK, the readcsv function provided in Base does not handle quotations well whereas the csv parser in DataFrames is slow, so that julia does not have yet a native efficient way to parse csv files.
