## Forum archive 2000-2006

### Danny Glin - Answer blank bug

by Arnold Pizer -
Number of replies: 0
 Answer blank bug topic started 10/16/2002; 8:19:05 AMlast post 10/22/2002; 2:35:14 AM
 Danny Glin - Answer blank bug  10/16/2002; 8:19:05 AM (reads: 1128, responses: 2) We just had an interesting phenomenon pop up. One of our questions includes answer blanks embedded in a LaTeX array (i.e. the answer blanks are a matrix). A student, in answering the question, inadvertently inluded a  within the number. She was marked incorrect, and when she went to reanswer the question, the answer boxes did not display. I assume this has something to do with the system misinterpreting  as a special character in formatted text mode, as the answer boxes still appear in plain text mode. We have resolved the issue for the student by recommending that she reattempt the question in formatted text mode, but check the "do not display my old answers" box. Just curious if anyone has seen this before, and if there is anything we can do about it. Danny Glin University of Calgary <| Post or View Comments |>

 Arnold K. Pizer - Re: Answer blank bug  10/16/2002; 11:30:22 PM (reads: 1408, responses: 0) Hi Danny, We are looking into this. Arnie <| Post or View Comments |>

 Arnold K. Pizer - Re: Answer blank bug  10/22/2002; 2:35:14 AM (reads: 1351, responses: 0) Hi Danny, As you say, this seems to be caused by tth treating  as a special character. The solution we have arrived at is to filter out  (along with $and @) from sticky answers. To do this yourself, edit the file .../webwork/system/courseScripts/PGbasicmacros.pl. Around line 248 in the sub NAMED_ANS_RULE, change $answer_value =~ tr/$@//d; ## make sure student answers can not be interpolated by e.g. EV3 to $answer_value =~ tr/\$@//d; ## make sure student answers can not be interpolated by e.g. EV3` Arnie <| Post or View Comments |>