Issue with ParserAssignment.pl

[dlglin]

There is an issue with ParserAssignment.pl when a student enters an answer for which PG can't generate enough points for comparison. This was discovered with Library/FortLewis/DiffEq/1-First-order/05-Substitution-Bernoulli/Lebl-1-5-06.pg. A MWE is attached.

Steps to reproduce:
In one of the above problems, enter an answer that is not defined on the domain (e.g. "y=sqrt(x-5)"), and click either Preview or Submit. Now enter a correct answer and click Submit. You will receive the error "The evaluated answer is not an answer hash : ||.", and the answer will be marked wrong.

It looks like this has something to do with the check for equivalence to the previously submitted answer.

ParserAssignmentMWE.pg.txt

[drdrew42]

I am unable to reproduce your error -- neither with Library/FortLewis/DiffEq/1-First-order/05-Substitution-Bernoulli/Lebl-1-5-06.pg, nor the MWE provided.

[dlglin]

Did you try submitting a correct answer after that answer?

[drdrew42]

sigh -- apparently I can only read a couple sentences before my brain shuts off.

Confirmed, will investigate.

[pstaabp]

Following up on this one. This does fix the initial error from the OPL problem and the MWE.

There is still the warning about not generating enough points. I understand the issue, but what do students do with this information--except ask the instructor. And most instructor's don't understand this.

I think this should be closed but perhaps generate a more-helpful warning.

[pstaabp]

This has been fixed by #609 and #645