[QTI] tolerance attribute in equal expression

[Steve Lay]

At 15:49 +0200 2006-05-19, Marina Zelwer wrote:
>I've got a problem with the tolerance attribute of the equal expression
>(QTI2.1). If I understoud the documentation, if I want a tolerance like :
>[x-t0,x+t1]
>the tolerance attribute has to appear twice, once for the value of t0
>and once for the value of t1.

Firstly, if t0 and t1 are the same then you can give it once only and
you're done.  "If only one value is given it is used for both."

However, if you have two different values then they must both be put into a
single instance of the tolerance attribute.  It is true that the order of
attributes within an element is not significant in XML but the order of
items within a space-separated attribute value is significant.

In other words:

<myElement attr1="A" attr2="B"> is the same as <myElement attr2="B" attr1="A">

But:

<myElement attr1="A B"> is not the same as <myElement attr1="B A">

The tolerance attribute uses the latter form in the binding.

What does need clarification is the fact that t0 appears first when bound.
It is almost explicit in the names "t0" and "t1" but it should be spelt
out: should be fixed in the next release of the documents.

Thanks for drawing this to our attention.

Steve