Handling input errors via startup codes

  • Hi, Math app questions facilitate a nice automatic 'communication' with the student via MapleTA, concerning e.g. the syntactical correctness of the student's input before evaluation and grading. I have managed to use the try-catch statement on parsed string versions of the students input in startup codes for this purpose, but in simple cases only. The procedure will disclose simple syntax errors (wrong number of parentheses etc.) without creating halting error messages at the student's front end and at the same time allowing the student to reset and correct his/her input. My question is this: Is there a general way to set up a Maple procedure in the startup code which in the same way will take in an expression (including errors) from the student and return - not the error statement, but a last exception type statement, that can then be communicated from the math app startup code in a controlled way  to the student to be used effectively for resetting and correcting his/her input? I hope it makes sense? Thank you in advance for any suggestions in this direction! Best, Steen