[xacml] [Polar] PH09: New section 7.4.2 Attributes

[Seth Proctor <seth.proctor@sun.com>]

While working on our implementation, I noticed the problem of AD/AS types
always returning bags but almost all standard functions requiring single base
types (and therefore rejecting bags as input). I suggested that one way to
solve this was to treat a bag with a single item the same as that single item
on its own. Text was proposed for this change. There was no discussion on the
list, but the updated change list from Thursday afternoon suggests that this
change suggestion was rejected, with no explination except "Use anyOf."

Since "Use anyOf" doesn't apply to my change request, and since there is no
other explination for why this was rejected or how I'm supposed to treat
this problem, I am asking my question again: how are functions that expect
single values supposed to deal with the bags that are required to be returned
from AD/AS types? I will once again suggest that text be added that makes
it clear that bags with one element are treated the same as just that one
element on its own. I will also point out that trying to solve this problem
by wrapping AD/AS types in functions that select single values from bags will
result in much larger (and more copmlex) policies, and will increase processing
time dramatically, since all standard functions will require this wrapping.
Making the simple change I have suggested will prevent both of these problems.


seth