JSON Profile Revision

[Steven Legg <steven.legg@viewds.com>]

I'm currently editing the JSON profile to remove all the cases where there was a
choice between a single object and an array and making it always an array, but I've
noticed a couple of things that warrant attention.

There are a couple of cases where an array is required to have at least one value,
and hence is mandatory, but all the rest are optional. The profile doesn't say
whether an empty array is acceptable for these optional cases. What should the
profile have to say about empty arrays? In my implementation I allow an empty array
and treat it the same as the type/value pair being absent since the XML
representation is the same either way. I avoid outputting a type/value pair if the
array would be empty.

The second thing is that the optional "Content" type/value pair is allowed to have a
null value. This is the only case where null is allowed. The situation is
analogous to the empty array case in that it makes no difference to the XML
representation whether a type/value pair is absent or the value is null. However,
I propose to disallow null in this case and to make a general statement in the
profile that null isn't used. By analogy we could outlaw empty arrays too, but they
are easy to deal with when parsing. Opinions?

I've sent much the same message to the XACML comment list to get opinions from
there.

Regards,
Steven