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Re: The reason for roots?

From: Martin Gudgin <marting@develop.com>
Date: Fri, 22 Mar 2002 09:57:57 -0000
Message-ID: <00d101c1d188$0cdef3e0$b47ba8c0@zerogravitas>
To: "Jacek Kopecky" <jacek@systinet.com>
Cc: "XML Protocol Discussion" <xml-dist-app@w3.org>
Ahh, OK I think I see what's going on here. A graph may or may not have a
root. The graph you show below has no root. BUT there still has to be at
least one start point for serialization. Having said that does that
information need to be carried in the envelope? Why does the deserializer
need A and/or B to be labeled root='true' in your example below?

Gudge


----- Original Message -----
From: "Jacek Kopecky" <jacek@systinet.com>
To: "Martin Gudgin" <marting@develop.com>
Cc: "XML Protocol Discussion" <xml-dist-app@w3.org>
Sent: Thursday, March 21, 2002 3:14 PM
Subject: Re: The reason for roots?


> Gudge,
>  I disagree with the first fact you listed below. In a general
> graph there can be no such node (your fact 4). I thought we were
> talking about "serialization roots" which are the nodes from
> which serialization starts.
>  The second fact I also disagree with because you can have a
> graph like
>
> +---+   x
> | A |------+     (the nodes are named for the sake
> +---+      |        of referencing them in my text)
>            V
> +---+ y  +---+
> | B |--->| C |
> +---+    +---+
>
> and then you can serialize A into a header and serialize B into
> the body (or a different header).
>  But if we do forbid the "independent" elements (as indicated in
> the thread starting with my message [1]) the root shall (or
> should) always be apparent from its context and from the
> application specification.
>  On the other hand, this issue is also affected by the result of
> the discussion on encodingStyle on Header and Body because I
> think that if we put encodingStyle on Header, it clearly becomes
> a serialization root. 8-) Then we'd have to allow arbitrary
> attributes (root attributes from different encodings) on Header.
> Same for Envelope. Not really nice I think.
>  Best regards,
>
>                    Jacek Kopecky
>
>                    Senior Architect, Systinet (formerly Idoox)
>                    http://www.systinet.com/
>
> [1] http://lists.w3.org/Archives/Public/xml-dist-app/2002Mar/0137.html
>
>
> On Thu, 21 Mar 2002, Martin Gudgin wrote:
>
>  > During the recent rework on Part 2 Section 2 and 3 I spent quite a
while
>  > thinking about roots as they relate to the data model. It may be that
my
>  > imagination is not firing on all cylinders but here are the 'facts' as
I see
>  > them;
>  >
>  > 1.    A root is a node with no inbound edges
>  >
>  > 2.    There is a path from a root node to all other nodes in the graph
>  >
>  > 3.    Given 1 and 2 it *is not* possible to have more than one root
>  >
>  > 4.    Given 1 and 2 it *is* possible to have a graph with no root
>  >
>  > So, I'm at a loss as to why I would want to label a given node as the
root
>  > of the graph unless it's to avoid the deserializer having to work it
out by
>  > inspection. Is this the reason?
>  >
>  > All input gratefully received
>  >
>  > Gudge
>  >
>
Received on Friday, 22 March 2002 04:56:45 GMT

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