Re: XML Overlays and Deltas: Existing methods? Ideas?

["Stephen D. Williams" <sdw@lig.net>]

Joel Bender wrote:
...
> >This problem is the same regardless of the form of XML, but I am
> >planning to use some solution to this as part of my binary structure
> >XML work.
> 
> So the change description is encoded in binary XML?  Or are you
> describing changes to a binary XML document?

The idea is to use binary structure for an XML document and it's
deltas.  The issue of binary data payloads, beyond the obvious for what
would be base64, is left as another 'compression' layer issue.

> 
> >Some ideas to beat up on...
> 
> Humm...
> 
> ><XML ID="ob1">
> >   <update xpath="author/book["Bob's Life"]/sold">98</update>
> ></XML>
> 
> The double quotes bother me a little, something might need to be
> escaped, but the basic idea matches my thoughts.

Yea, that was a little too quickly typed.

> 
> ><u:u ID="E9F">98</u>
> 
> Have you thought about insert/append issues?  Are whitespace-only
> text nodes considered significant in your plans?

Yes, to some extent.  insert/append is needed.  A path to an object
would indicate appending.  A path to an object in array syntax would
imply insert before.  That kind of thing.

Whitespace-only text nodes are best kept verbatim in the simple version
of a generic system.  I plan to handle whitespace in an efficient way. 
Possibly a default case would be treated as implied.  For instance, a
standard indent/lf combination would not generate any whitespace output
unless there was text in a node.

> 
> Joel

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Stephen D. Williams
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Dec2000