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Re: [xml-dev] RE: [xquery-talk] Re: [xml-dev] Serialization of XDM - Use cases /Proposal

From: David A. Lee <dlee@calldei.com>
Date: Fri, 18 Sep 2009 20:06:51 -0400
Message-ID: <4AB4209B.5050704@calldei.com>
To: Michael Kay <mike@saxonica.com>
CC: talk@x-query.com, xml-dev@lists.xml.org, "'XProc Dev'" <xproc-dev@w3.org>
Thanks Michael.  I think my next step will be to document what 
attributes of XDM should be maintained through serialization and what 
will be dropped.
I agree that Node Identity is not something that can reasonably be 
maintained.
Ancestry is an interesting concept I hadn't considered ...
e.g. if you serialize a node $node ... its not expected that a 
reconstituted XDM  $node could evaluate  $node/..

Schema equivilence is interesting, I was thinking of addressing (or 
punting !) that concept with type information.
Ignoring (or assuming) common xsd:* types ...

If for example a value is of type   mytype:abc  ... I think agree its a 
good presumption that the target environment has access to the same types.
Otherwise we open the box of having to serialize all the type 
information along with the XDM values. Good call.




David A. Lee
dlee@calldei.com  
http://www.calldei.com
http://www.xmlsh.org
812-482-5224



Michael Kay wrote:
> Good start.
>
> The next section before you go into specification should perhaps be
> "Requirements", including assumptions and constraints. This might include
> statements such as:
>
> * Serialized XDM will retain information about the descendants of nodes in
> the sequence being serialized, but it will not retain information about
> their ancestors.
>
> * Serialized XDM will not retain information about node identity: that is,
> the recipient of the serialized XDM will not be able to determine whether
> two serialized elements originated from the same node or merely from two
> nodes that were deep-equal to each other.
>
> * The consumer of the serialized XDM is assumed to have access to the same
> schema as the producer of the serialized XDM: that is, a QName identifying a
> type is assumed to have the same meaning to both the producer and consumer.
>
> * If A and B are two XDM sequences, then xml-canonicalize(xdm-serialize(A)))
> is codepoint-equal to xml-canonicalize(xdm-serialize(B))) if and only if
> fn:deep-equal(A, B). [Actually, that's probably not a good requirement,
> because fn:deep-equal() discards comments and PIs and you probably don't
> want to do that].
>
> These are just example statements, you might want to substitute different
> ones: they are just intended to illustrate the kind of thing that needs to
> be said.
>
> Regards,
>
> Michael Kay
> http://www.saxonica.com/
> http://twitter.com/michaelhkay 
>
>   
>> -----Original Message-----
>> From: talk-bounces@x-query.com 
>> [mailto:talk-bounces@x-query.com] On Behalf Of David A. Lee
>> Sent: 18 September 2009 22:07
>> Cc: talk@x-query.com; xml-dev@lists.xml.org; XProc Dev
>> Subject: [xquery-talk] Re: [xml-dev] Serialization of XDM - 
>> Use cases /Proposal
>>
>> I have created a first pass at documenting the problem of XDM 
>> Serialization and created some use cases.
>> I would love any feedback or comments.  This is on a new wiki 
>> I created for this purpose.  If you would like to comment 
>> directly on the wiki please reply to me and I will give you 
>> the invite code (due to the sad state of affairs anonymous 
>> comments and editing are disabled due to wiki-spam-bots.  
>> I've found spam within 5 minutes of opening a public wiki ... <sigh> )
>>
>>
>> http://xml.calldei.com/XDMSerialize
>>
>> I have NOT included a proposal for a format yet, I'd like to 
>> discuss the intent and use cases first before putting up a 
>> straw-man proposal.
>>
>> Thank you for any contribution !
>>
>> I've CC'd this to xproc-dev because one of the use cases if 
>> for developers and integrators with XML Pipeline processors 
>> such as XProc
>>
>>
>> David A. Lee
>> dlee@calldei.com  
>> http://www.calldei.com
>> http://www.xmlsh.org
>> 812-482-5224
>>
>>
>>
>> _______________________________________________
>> talk@x-query.com
>> http://x-query.com/mailman/listinfo/talk
>>     
>
>
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Received on Saturday, 19 September 2009 00:07:54 GMT

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