Custom marking algorithm question

[Jim Pettigrew]

Hi Christian (and all),

I'm getting some grief adapting a customised gap-fill question.

The line

this.__proto__.mark.apply(this);

in the custom marking algorithm for the question

https://numbas.mathcentre.ac.uk/question/89869/only-mark-a-gap-depending-on-the-answer-to-a-previous-gap

(and other similar questions) causes an error.

Are you able to explain why?

Thanks,

Jim

[Christian Lawson-Perfect]

Hi Jim,

The internals of the marking functions changed in Numbas v5 to accommodate alternative answers. The "mark student's answer" JavaScript now replaces Part.mark_answer, instead of Part.mark. Part.mark_answer takes two arguments, studentAnswer and scope, so you need to pass those when you call the built-in version. So the line should read:

  this.__proto__.mark_answer.apply(this,[studentAnswer,scope]);

But you don't need JavaScript to do the marking you want. It could be achieved using a JME marking algorithm, and those are a lot more stable than the JavaScript API.

In fact, the question you've set up would be even easier to implement in explore mode: you could decide whether to show the "enter the factorisation" part based on the student's answer to "does this equation have a factorisation?"

I hope that helps.

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[Jim Pettigrew]

Thanks very much Christian.

It does help.

I suspected the code I was using (borrowed from elsewhere) was deprecated in some way.

Based on your advice, I've rejigged the question without using this.__proto__.mark_answer.apply(this,[studentAnswer,scope]);

When I get a moment, I will try redoing the question in explore mode. This does seem to be the better - perhaps more generalisable - way of doing things.

Cheers,

Jim

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