W3C home > Mailing lists > Public > public-ws-policy@w3.org > May 2007

Policy expression meaning different if in alternative?

From: Frederick Hirsch <frederick.hirsch@nokia.com>
Date: Tue, 8 May 2007 17:58:55 -0400
Message-Id: <4FDFC8B2-6174-4241-9FEC-A27306C1127F@nokia.com>
Cc: Hirsch Frederick <frederick.hirsch@nokia.com>
To: ws policy <public-ws-policy@w3.org>

Did we ever articulate a simple answer to Anish's question [1]:

> One not obvious (not to me) side-effect of this 'negation' is the  
> following:
>
> Consider the scenario where two very complicated polices are  
> created by the IT department. Let's call them P1 and P2. I'm  
> required to use P1 or P2 on services that are exposed outside the  
> firewall. P1 contains an assertion A that is absent in P2. If I  
> advertise P1 only then I have to do whatever A asks me to do. If I  
> advertise P2 only, I may or may not use A (as it is not part of the  
> vocabulary) -- it is up to me. If I advertise a policy that says  
> either of P1 or P2 and P2 is selected, I cannot use A. This is very  
> surprising (at least to me). This does not follow the 'principle of  
> least surprise'. "OR"ing operation in other contexts does not  
> introduce negation based on vocabulary set. I'm curious as to the  
> rationale for this. In any case, guidance and clarification in the  
> spec or the primer would be very useful.

Is the answer that when P1 and P2 are policy alternatives then they  
have different meaning than when as stand-alone policies due to  
vocabulary?

regards, Frederick

Frederick Hirsch
Nokia

[1] <http://lists.w3.org/Archives/Public/public-ws-policy/2007Apr/ 
0086.html>
Received on Tuesday, 8 May 2007 21:59:03 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:38:34 UTC