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RE: Untargetted blocks (was Re: Must understand mustUnderstand pr oposal)

From: Williams, Stuart <skw@hplb.hpl.hp.com>
Date: Wed, 9 May 2001 12:47:25 +0100
Message-ID: <5E13A1874524D411A876006008CD059F19241D@0-mail-1.hpl.hp.com>
To: "'Hugo Haas'" <hugo@w3.org>
Cc: xml-dist-app@w3.org
Hi Hugo,

<snip/> 

> In the abstract model draft[1] dated 27 March 2001, section 4.1 reads:
> 
>     4. There are reserved actor URI's with special significance
>        (actual path to be determined):
>        http://.../none    // an untargeted block (may be referenced by
>        other blocks)
> 
>        SOAP forces the actor for body entries to be the final
>        processor.  Untargeted blocks (http://.../none) have no
>        correlate in SOAP.
> 
> This was removed in the 30 March 2001 version[2]:
> 
>     Changes from Draft of 27th March 2001
>   [..]
>     4. Replaced section 4.1 (now section 4.2) with new text from Mark
>        Jones
> 
> I have seen discussion[3] between Mark and yourself about these
> untargetted/anonymous blocks, but I could not find why they
> disappeared. Could somebody point me to an explanation?

I don't think that they have disappeared (unless I have misunderstood your
question). 

In [3] the text became:

<quote>
4. There are reserved actor URI's with special significance (actual syntax
to be determined):
  .../none    // an untargeted block (may be referenced by other blocks)
  .../next    // matches the next processor (basically a wildcard that
matches any processor)
  .../final  // matches the final processor

An empty actor defaults to final.    An untargeted block marked with actor
none is useful for declarative information that is referenced by another
block or blocks.  It is guaranteed not to be removed and can even be
referenced by blocks which are targeted at different processors.
</quote>

The intent as I understood it being to not encumber the AM with a particular
concrete syntax for abstract notions of 'none', 'next' and 'final'. 

In the current AM document dated 23rd April [4] the same text has lost the
ldots to become:

<quote>
4. The following values for Block.Actor have special significance:
\bold{Next}, \bold{Final}, and \bold{None}.  Next matches the next
processor.  Final matches the final processor.  None is for untargeted
blocks which may be referenced by other blocks.

An empty actor defaults to Final.   An untargeted block marked with None is
useful for declarative information that is referenced by another block or
blocks.  It is guaranteed not to be removed and can even be referenced by
blocks which are targeted at different processors
</quote>

Basically, in the AM it seemed appropriate to denote these actor concepts,
but not to mandate the concrete syntax that should be used to express these
concepts in an XMLP/SOAP message - that lies in the domain of the spec.
itself.

Hope this helps (and answers the right question :-)).

> 
> Thanks.
> 
>   1. http://www.w3.org/2000/xp/Group/1/03/27/XMLProtocolAbstractModel.html
>   2. http://www.w3.org/2000/xp/Group/1/03/30/XMLProtocolAbstractModel.html
>   3.
http://lists.w3.org/Archives/Public/xml-dist-app/2001Mar/thread.html#68
> -- 
> Hugo Haas - W3C
> mailto:hugo@w3.org - http://www.w3.org/People/Hugo/ - tel:+1-617-452-2092

Regards

Stuart

[4] http://www.w3.org/2000/xp/Group/1/04/23/XMLProtocolAbstractModel.html
Received on Wednesday, 9 May 2001 07:47:50 GMT

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