MP4 will give you practice writing a parser for the Hask language. This again includes a grader, as well as precompiled versions of the solutions for the parser and for the lexer from MP3. Please read the MP handout for more details.
UPDATE: Please grab the new solution files. You can unzip these over your current files without risk of losing your work.
UPDATE: Please grab the hasklex.mll file and the updated Makefile.
Also, make sure you read the "Guide for Doing MPs".