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Re: [PRD] Issues to resolve before publication (Assign/Modify)

From: Gary Hallmark <gary.hallmark@oracle.com>
Date: Mon, 30 Jun 2008 12:47:11 -0700
Message-ID: <4869383F.9000901@oracle.com>
To: Christian de Sainte Marie <csma@ilog.fr>
CC: RIF WG <public-rif-wg@w3.org>



Christian de Sainte Marie wrote:
> Gary Hallmark wrote:
>>>
>>> #6. Section 2.2 (Actions): Assign or not Assign in FPWD? I propose 
>>> to keep it, now that it has been re-included with Ed: Adrian wants 
>>> it, Mark
>>> wants it, I am rather in favor, Gary balances. I added an editor's 
>>> note in section 2.2.1.3 (Assign) to the effect that this was still 
>>> under discussion and that the syntax was liable to evolve.
>>>
>>> Gary, I see that you changed the examples: I did not check exactly 
>>> how, but if we agree on the above solution, you will have to revert 
>>> that change, right?
>>
>> No, I will not revert the change because the syntax that was there 
>> did not work.  Because, as you say, the semantics of assign is 
>> exactly the semantics of retract+assert, and we have no better syntax 
>> than retract+assert, one wonders why we want an assign action.  If 
>> someone has a better syntax than retract+assert, then please propose it.
>
> Because all PR languages have it, in one form or another? Is that a 
> good-enough argument for having a modify operation in addition to 
> retract and assert?
only if the languages agree on the semantics, which I doubt...
>
> Btw, the reason why I think that the current Assigne(Frame) syntax 
> does not work has nothing to do with its semantics being the same as 
> retract+assert: it is rather that I see problems in confusing the 
> source and target in one same Frame expression.
which is why I said that if nobody proposes a clear and unconfusing 
syntax, we should definitely drop this
>
> Also, Assign, like other forms of "modify", differs from 
> retract+assert, in particular when objects are deleted and created. 
> Since, in this WD, the semantics of assert and retarct does not deal 
> explicitely with that case, the semantics of assign seems to resolve 
> to retract+assert; but if its semantics being incomplete is a reason 
> to remove Assign, the same should apply to Assert and Retract too!
no, you misunderstood me.  I am happy with the semantics.  We don't have 
a syntax.
>
> I modified the editor's note about the semantics of actions to mention 
> specifically that it needed be refined wrt the creation and deletion 
> of objects. Does that help?
I think that is a separate issue, and we need to discuss using Skolem 
functions for creation, to maximize Core, and we maybe we need 
Retract(?obj # Class)
>
> Cheers,
>
> Christian
>
Received on Monday, 30 June 2008 19:49:55 GMT

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