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Danny Glin - Answer blank bug

Danny Glin - Answer blank bug

by Arnold Pizer -
Number of replies: 0
inactiveTopicAnswer blank bug topic started 10/16/2002; 8:19:05 AM
last post 10/22/2002; 2:35:14 AM
userDanny Glin - Answer blank bug  blueArrow
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

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userArnold K. Pizer - Re: Answer blank bug  blueArrow
10/16/2002; 11:30:22 PM (reads: 1408, responses: 0)
Hi Danny,

We are looking into this.

Arnie

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userArnold K. Pizer - Re: Answer blank bug  blueArrow
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

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