The project requirements state that we need to catch usage errors and syntax errors. While it is stated that syntax errors must be reported to stderr beginning with a "!", I'm not sure what the following "@" character for debug printing is referring to. My thoughts are that Usage errors from the command line will be caught like we have been doing in the labs previously ("Usage:..."), while with the syntax errors we might print ("!Syntax Error"). Would the debug printing be another line after that commencing with "@" which would detail more explicitly what the syntax error is? Do we even need to explicitly detail what kind of syntax error occurred? Thanks.

ANONYMOUS wrote: Syntactic errors in an ml program should be reported on a line beginning with a '!', such as ! unrecognised statement They are different to any other debug statements that you wish to print out, such as @ now in function process_statement which you may use to simply explain (to yourself) what your runml program is doing, or where it's up to. Make more sense?

Hello! Thank you for explaining! I still have a question. Does this mean that there shouldn't be any "@" statements in the official submission since it is for your own debugging? Or it's okay to submit without removing the debugging statements as long as they commence with "@"? Or is it required to write some "@" statements in the final submission? Thank you!