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Re: The reason for roots?

From: Jacek Kopecky <jacek@systinet.com>
Date: Thu, 21 Mar 2002 16:21:09 +0100 (CET)
To: Martin Gudgin <marting@develop.com>
cc: XML Protocol Discussion <xml-dist-app@w3.org>
Message-ID: <Pine.LNX.4.44.0203211618590.16766-100000@mail.idoox.com>
 Oh, I apologize to those who have proportional fonts and
therefore can't properly see my ASCII-art. 
 The graph below is a node A, with outgoing edge 'x' to node C;
and a node B, with outgoing edge 'y' to node C.
 I don't think the graph is a lesser graph just because it has 
two roots, either. 8-)
 Best regards,

                   Jacek Kopecky

                   Senior Architect, Systinet (formerly Idoox)
                   http://www.systinet.com/



On Thu, 21 Mar 2002, Jacek Kopecky wrote:

 >  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 Thursday, 21 March 2002 10:21:10 GMT

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