[QTI] tolerance attribute in equal expression

[Steve Lay]

At 17:09 +0200 2006-05-19, Marina Zelwer wrote:
>Thanks a lot for your answer.
>What made me think that the tolerance attribute should appear twice when
>whe want two different values for t0 and t1 is the cardinality :
>"Attribute : tolerance [0..2]"
>given in the documentation.

This notation is supposed to be a UML-style statement of multiplicity but,
strictly speaking, the ordering and uniqueness of the attribute should also
be given as the default UML property values are unordered and unique - the
complete opposite of what we generally want.  In other words it should
actually read:

Attribute: tolerance [0..2 ordered nonunique]

As an aside, I always think this default is unfortunate for attributes,
where the absence of an ordering seems (superficially) to be more naturally
bound to an integer-based array concept (normally language native) than the
more complex set (unordered unique) and bag (unordered nonunique) types.
Perhaps there is a different default when interpreting multiplicity on
attribute definitions, I don't know my UML 2.0 specification well enough to
be sure.

As an open question to this audience, would you prefer the explicit
properties of the multiplicity to be listed in the specification?

Steve